Approval, Exhaust Gas Monitoring, and Safety Requirements for the Use of Diesel-Powered Equipment in Underground Coal Mines; Final Rule

[Federal Register: October 25, 1996 (Rules and Regulations)]
[Page 55462-55512]

 
[[pp. 55462-55512]] Approval, Exhaust Gas Monitoring, and Safety Requirements for the 
Use of Diesel-Powered Equipment in Underground Coal Mines

[[Continued from page 55461]]

[[Page 55462]]

Sec. 75.1909. This scheme was consistent with the recommendations of 
the Diesel Advisory Committee. Nonpermissible equipment that did not 
meet the criteria of the limited class would have been subject to fully 
assembled machine approval under subpart I of part 7, and would also 
have been required to be equipped with a power package approved under 
subpart G of part 7. Power packages provide the equipment with safety 
features such as surface temperature controls, exhaust temperature 
controls, and safety shutdown capability.
    Although the proposal anticipated fully assembled machine approval 
of both permissible and nonpermissible diesel-powered equipment, MSHA 
specifically solicited comments on whether nonpermissible diesel-
powered equipment should be approved by MSHA in an advance notice of 
proposed rulemaking published on the same day as the proposed rule. 
Many commenters to the proposal and to the advance notice were strongly 
opposed to fully assembled machine approval for nonpermissible 
equipment, stating that it was neither necessary for safety nor 
consistent with MSHA's approach to electrical equipment. These 
commenters stated that approval of nonpermissible diesel equipment 
would create significant technical hurdles and place unnecessary 
financial burdens on mine operators, without any justification from a 
safety perspective. These commenters recommended that the final rule 
set performance-oriented safety requirements for nonpermissible 
equipment in mandatory standards in part 75, and that the safety 
features that were proposed for the limited class of light-duty 
equipment in Sec. 75.1909 be applied to all nonpermissible equipment.
    Many commenters were also opposed to the proposed requirement that 
most nonpermissible equipment have a power package approved under 
subpart F or G of part 7. Commenters stated that the protections 
afforded by a power package were unnecessary for equipment operated in 
areas of the mine where methane is not likely to accumulate, and that 
much of the nonpermissible diesel-powered equipment currently in use 
would have to be either scrapped or significantly retrofitted to comply 
with the proposed requirements, at tremendous expense. Several 
commenters pointed out that it would be impossible to retrofit some 
types of equipment because of design limitations.
    Other commenters supported full machine approval and power packages 
for all nonpermissible equipment, and further recommended that all 
diesel-powered equipment in underground mines be permissible and 
equipped with the explosion-proof equipment features required in areas 
of the mine where coal is extracted and where higher methane levels are 
a concern.
    The final rule responds to commenters opposed to full machine 
approval for nonpermissible equipment, and does not adopt the proposed 
requirement for power packages on most nonpermissible equipment. It 
should be noted, however, that all nonpermissible equipment, with the 
exception of emergency equipment under Sec. 75.1908(d), is required to 
have an engine approved under subpart E of part 7.
    In evaluating whether an approval program for nonpermissible 
diesel-powered equipment was warranted in the final rule, MSHA 
considered whether the machine safety features set forth in proposed 
Sec. 75.1909 for the limited class of light-duty equipment could be 
modified to provide adequate protection for heavy-duty equipment. This 
review revealed that many requirements in proposed Sec. 75.1909 could 
be applied directly to heavy-duty equipment without revision, while 
other proposed requirements could be made suitable with slight 
revisions.
    The safety features proposed in Sec. 75.1909 for limited class 
equipment have been adopted in the final rule in Secs. 75.1909 and 
75.1910 to cover equipment that is larger and more powerful than what 
would have been covered under the proposed rule. This is in response to 
a number of commenters who believed that these proposed requirements 
should be applied to both heavy-duty and light-duty equipment, in lieu 
of a full machine approval program. In general, the proposed 
requirements have not been substantially changed in the final rule, 
although the final rule does adopt several additional requirements for 
heavy-duty equipment based on requirements in part 36 or developed from 
existing part 75 requirements applicable to electric-powered machines. 
Other additions or revisions have been made in response to comments 
received on proposed Sec. 75.1909 and in response to the advance notice 
of proposed rulemaking.
Section 75.1909  Nonpermissible Diesel-Powered Equipment--Design and 
Performance Requirements
    Section 75.1909 establishes design and performance requirements for 
diesel-powered equipment used where nonpermissible electric equipment 
is permitted, with the exception of the special category of equipment 
under Sec. 75.1908(d). The requirements of this section are consistent 
with the recommendation of the Advisory Committee that such equipment 
be provided with fire suppression system and fuel and electrical system 
protection. All nonpermissible equipment, with the exception of the 
special category of emergency equipment under Sec. 75.1908(d), is also 
required to be provided with an approved engine within the time frames 
established in Sec. 75.1907 of the final rule.
     Paragraph (a)(1), like the proposal, requires that nonpermissible 
diesel-powered equipment be equipped with an engine approved under 
subpart E of part 7. The final rule also requires that the engine be 
equipped with an air filter and an air filter service indicator. The 
air filter must be sized and the service indicator set in accordance 
with the engine manufacturer's recommendations.
     Some commenters stated that approved engines were not necessary on 
outby equipment. Other commenters recommended that all equipment used 
in outby areas be provided not only with an approved engine, but also 
with a permissible power package approved under subpart F of part 7.
     The final rule adopts the proposed requirement that nonpermissible 
equipment be provided with an approved engine. Engines approved under 
subpart E of part 7 must meet specific gaseous emission standards and 
be provided with an approval plate indicating the quantity of 
ventilating air needed to dilute gaseous contaminants to acceptable 
levels. These requirements not only place limits on the quantity of 
gaseous contaminants that an approved engine may produce, they also 
provide a scheme for control of those contaminants through effective 
ventilation. Commenters expressed serious concern over unhealthful 
exhaust emissions from diesel equipment in outby areas that may 
significantly affect the quality of air that miners breathe. In 
response to these concerns, the final rule takes a comprehensive 
approach in addressing health hazards presented by diesel exhaust, and 
requires clean-burning engines, approved by MSHA under subpart E of 
part 7, on all diesel-powered machines, including nonpermissible 
equipment. Engines installed in this equipment must therefore meet the 
emissions standards established in subpart E of part 7.
     The final rule does not adopt the suggestion of commenters who 
supported requiring all diesel equipment in underground coal mines

[[Page 55463]]

to be permissible. The explosion- proof features provided by a subpart 
F power package are not needed for outby equipment, because the 
equipment operates in areas of the mine where methane is not expected 
to accumulate. Electrical equipment without explosion-proof features 
has been operated safely in outby locations for many years.
     The requirement that the engine be equipped with an air filter and 
an air filter service indicator has been added in response to 
commenters'' statements that clogged air filters were the single most 
frequent cause of smoky engines, resulting in the production of 
disproportionate quantities of carbon monoxide and diesel particulate. 
These components are typically supplied as part of the equipment, and 
the air filter service indicator will enable the equipment operator and 
maintenance personnel to ensure that the air filter is in good 
condition. Both the size of the air filter and the setting of the air 
filter service indicator are best determined by the engine 
manufacturer, and the final rule requires that these be determined in 
accordance with the engine manufacturer's recommendations.
    Paragraph (a)(2) has been added to the final rule and requires that 
nonpermissible equipment be provided with at least one portable 
multipurpose dry chemical type (ABC) fire extinguisher, listed or 
approved by a nationally recognized independent testing laboratory, and 
having a 10A:60B:C or higher rating. The extinguisher must be located 
within easy reach of the equipment operator and be protected from 
damage. This requirement has been added to the final rule in response 
to a commenter who supported requiring two chemical fire extinguishers 
accessible to each end of the unit and protected from external damage. 
MSHA agrees with this recommendation, which is consistent with good 
fire prevention practices and which will provide additional fire 
protection on diesel-powered machines. One rather than two fire 
extinguishers has been required, however, because one extinguisher, 
accessible to the operator and protected from damage, is adequate for 
virtually all diesel-powered equipment. As discussed elsewhere in the 
preamble, this equipment is also required to be equipped with either an 
automatic or manual fire suppression system, depending on the equipment 
category.
     Paragraph (a)(3) has been adopted from the proposal, and requires 
that the equipment's fuel system be specifically designed for diesel 
fuel, and that it meet specific additional criteria. One commenter 
recommended that this provision be revised to require a fuel system 
``specifically designed and constructed to minimize the possibility of 
a fire in case of a collision or refueling''. The commenter stated that 
fuel tanks on most light-duty equipment, such as pickup trucks, already 
meet certain standards, and that it would be unwise from a safety 
standpoint to modify these tanks. The final rule has not been revised 
in response to this comment. The fuel system requirements in the final 
rule are designed to address safety hazards presented by the use of 
diesel equipment in the underground mine environment, and nonspecific 
concerns about retrofitting equipment do not outweigh the protections 
afforded by the fuel system criteria included in the final rule. 
However, a fuel system that meets applicable industry standards would 
be acceptable so long as it also meets the criteria in paragraphs 
(a)(3)(i) through (xi).
     Paragraph (a)(3)(i) provides that the fuel system must have a fuel 
tank and fuel lines that do not leak. The proposed rule, unlike the 
final rule, would have required that the fuel tank be of ``leakproof 
construction.'' Several commenters stated that the term ``leakproof 
construction'' was ambiguous and needed to be defined in the final 
rule, or be revised to provide for construction that was ``designed to 
prevent leaks''. Rather than providing a definition for ``leakproof 
construction'' and specifying design or construction requirements to 
protect against leakage, the final rule sets a performance standard and 
simply requires that the fuel tank and fuel lines not leak, allowing 
mine operators the flexibility to determine how to best comply with 
this requirement. Fuel lines have been included in this requirement 
under the final rule, in response to commenters who were concerned 
about fire hazards presented by leaking fuel lines on diesel-powered 
equipment coming into contact with hot engine surfaces.
     Paragraph (a)(3)(ii) adopts the proposed requirement that the fuel 
tank be substantially constructed and protected against damage by 
collision. Commenters generally supported this requirement. The tank 
may be protected from damage by collision by being located within the 
frame components of the machine, or be constructed of material that is 
sufficiently sturdy so that the tank will not be damaged by collision 
with other vehicles or with the mine roof, rib, or floor. It should be 
noted that although the term ``tank'' is used in the singular here and 
in other paragraphs of this section, the final rule is not intended to 
limit the number of tanks on equipment. Several models of pickup trucks 
are manufactured with dual fuel tanks, and this configuration is 
acceptable under the final rule.
     Paragraph (a)(3)(iii) requires that the fuel system be provided 
with a vent opening that maintains atmospheric pressure in the tank, 
and which is designed to prevent fuel from splashing out. The proposed 
rule would have required that the size of the vent prevent fuel from 
splashing out of the vent opening. This requirement has been modified 
slightly in the final rule to specify that the design rather than the 
size of the vent opening must prevent fuel from splashing out, in 
response to commenters who advocated requirements that were more 
performance-oriented. This minor revision will allow mine operators 
increased flexibility in satisfying this requirement. MSHA anticipates 
that the vent provided in the fuel filler cap will satisfy this 
requirement.
     Paragraph (a)(3)(iv) requires a self-closing filler cap on the 
fuel tank. The proposed rule would have required either a tethered cap 
or a self-closing cap. The final rule requires a self-closing fuel cap 
that will serve to minimize fuel spillage, and responds to commenters'' 
serious concerns about the hazards of fuel spillage.
    Paragraph (a)(3)(v) requires that the fuel tank, filler and vent be 
located so that any leaks or spillage during refueling will not contact 
hot surfaces. This requirement has been revised from the proposed rule, 
which would have required that these components be located to prevent 
fuel from contacting hot engine surfaces. The final rule has been 
revised from the proposal because of the application of the 
requirements of this section to all nonpermissible diesel-powered 
equipment, not just equipment falling in the proposed limited class. 
This modification recognizes that there are additional machine 
components, particularly on larger heavy-duty equipment, now falling 
under this requirement that reach temperatures that could ignite diesel 
fuel. For example, brake components can reach temperatures that are as 
high as engine temperatures.
    Paragraph (a)(3)(vi) requires that fuel line piping be either: 
steel-wire reinforced; synthetic elastomer-covered hose suitable for 
use with diesel fuel that has been tested and has been determined to be 
fire-resistant by the manufacturer; or metal. The proposal would have 
required metal fuel line piping. Several commenters stated that 
requiring fuel line piping to be made of metal was too restrictive. 
Several of these commenters stated that metal fuel

[[Page 55464]]

lines could deteriorate over time as a result of machine vibration, and 
that there were fuel lines made of other materials that were superior 
in strength and performance to metal lines. The final rule has been 
revised from the proposal to address these concerns. Synthetic 
elastomer-covered hose must be of a type that is suitable for use with 
diesel fuel, and must have been tested and determined to be fire-
resistant by the manufacturer, using any one of a number of fire-
resistance tests. Such tests have been developed by a number of 
organizations, including Underwriters Laboratories, The Society of 
Automotive Engineers, and the U.S. Coast Guard. MSHA's tests for flame-
resistance specified in regulations at part 18 would also be 
appropriate. This will ensure that material used for diesel fuel lines 
will have adequate fire-resistance in the underground coal mine 
environment.
    Paragraph (a)(3)(vii) adopts the proposed requirement that fuel 
line piping be clamped. One commenter stated that this requirement, 
along with the requirement that primary fuel lines be located so that 
fuel line leaks do not contact hot surfaces, would limit machine design 
flexibility. This commenter recommended that these requirements be 
revised to provide that the manufacturer's design provide maximum 
protection from damage. The final rule does not adopt this suggestion. 
The requirements identified by the commenter are intended to address 
potential hazards on diesel equipment, particularly fire hazards. The 
fact that there may be some resulting limitations on machine design, 
alone, does not warrant the elimination of requirements that address 
specific hazards.
    Paragraph (a)(3)(viii), like the proposal, requires primary fuel 
lines to be located such that leaks do not contact hot surfaces. The 
fuel lines referred to in this paragraph are the supply and return 
lines connecting the fuel tank to the engine, not those lines that are 
integral to the engine and installed by the engine manufacturer, such 
as the lines connecting the injector pump to the injectors. Several 
commenters supported this requirement, pointing to the potential for 
fire resulting from leaking fuel dripping on hot exhaust components. 
One commenter recommended that the engine be designed to shut down in 
the event of a leaking fuel line. This comment has not been adopted in 
the final rule, in part because MSHA is unaware of any existing 
technology that would provide such a function. Additionally, such a 
requirement is not necessary, given the fuel system design criteria 
under this section in conjunction with the weekly equipment inspections 
required by Sec. 75.1914 of the final rule. These requirements together 
adequately address the potential hazard created by leaking fuel lines.
    Paragraph (a)(3)(ix) requires fuel lines to be separated from 
electrical wiring and protected from damage in ordinary use. This 
requirement has been adopted from the proposal, and was supported by 
several commenters, who mentioned incidents where fuel lines were 
exposed to damage. Separation of fuel and electrical lines can 
generally be easily accomplished. On machines where both electrical 
lines and fuel lines are routed through a machine articulation joint, 
fuel lines must be bundled separately from electrical lines and must be 
positioned so that fuel leaks will not contact electrical lines.
    Paragraph (a)(3)(x) requires that a manual shutoff valve be 
installed in the fuel system as close as practicable to the tank. The 
language of the final rule has been modified from the proposal, which 
would have required the valve to be located ``near'' the tank. This 
change is made in response to a commenter who stated that valves 
located ``near'' the tank would not necessarily be easily accessible to 
the equipment operator or other mine personnel when the fuel supply 
needs to be shut off in an emergency or for maintenance. The commenter 
recommended that this aspect of the proposal be revised to require 
shutoff valves as close as practicable to the tank, and the final rule 
adopts this comment.
    Paragraph (a)(3)(xi) adopts the proposed requirement that equipment 
be provided with fuel filter(s) and a water separator. The final rule 
substitutes the term ``water separator'' for the term ``water 
strainer'' used in the proposal. The terms mean the same thing, but 
``water separator'' is more commonly used and more widely understood. 
Although commenters generally supported this requirement, one commenter 
stated this requirement should be eliminated because fuel filters and 
water separators were not necessary. MSHA disagrees with this 
commenter, and the proposed requirement has been included in the final 
rule. Fuel filters filter out particulate matter in fuel, thereby 
reducing diesel exhaust emissions as well as slowing engine wear. Water 
separators filter out water in the fuel, and minimize fuel system 
corrosion. Several commenters recommended that the proposed requirement 
be revised to permit the use of a single device that functions as both 
a fuel filter and a water separator. Such combination devices will 
satisfy the requirements of this section. The final rule has not been 
revised, however, because the language as proposed and as adopted in 
the final rule does not preclude the use of a combination fuel filter/
water separator.
    The proposed requirement for a fuel tank drain plug has not been 
adopted in the final rule. Although the drain plug is usually provided 
on larger mining equipment, it is typically not provided on light-duty 
equipment such as pickup trucks. Although a drain plug is a convenient 
feature for persons performing equipment maintenance, it is not 
necessary from a strict safety standpoint. For these reasons, a fuel 
tank drain plug is not required under the final rule.
    Paragraph (a)(4) adopts the requirement of the proposal for a 
sensor to monitor the temperature and provide a visual warning of an 
overheated cylinder head on air-cooled engines. This feature is 
necessary because it reduces potential fire hazards on air-cooled 
engines. While such sensors do not completely eliminate the hazards of 
hot surface temperatures, they do provide additional protection by 
warning the equipment operator of overheating. The proposed rule would 
have required a temperature sensor to be located in the engine 
compartment that would automatically activate an intake air shutdown 
device to stop the engine before the engine compartment temperature 
exceeded the actuation temperature of the fire suppression system. This 
requirement has not been adopted in the final rule. Although commenters 
generally supported the concept behind this requirement, they had 
varied concerns about its application and impracticality from a 
technological standpoint. One commenter stated that this requirement 
could create a safety hazard because the engine could be shut off 
unexpectedly. Since loss of steering and braking could result, this 
commenter recommended that the engine be shut off only upon actuation 
of the fire suppression system. Several commenters stated that use of 
manual fire suppression systems on equipment was incompatible with this 
requirement.
    MSHA agrees that this proposed requirement could have resulted in 
the equipment losing control of the machine in the case of unexpected 
engine shutdown, and the engine should only be shut down upon actuation 
of the fire suppression system. The automatic engine shutdown under the 
proposal would have been triggered before the engine temperature 
exceeded the actuation temperature of the fire suppression system. 
Section 75.1911(d)

[[Page 55465]]

of the final rule already requires fire suppression systems for diesel-
powered equipment to provide for automatic engine shutdown, and a 
redundant requirement for automatic engine shutdown at a lower 
temperature is not necessary. An increase in the engine compartment 
temperature may reflect an engine malfunction, such as loss of engine 
coolant, but does not necessarily indicate a safety hazard. Linking 
engine shutdown to the engine compartment temperature would have 
provided protection against engine damage rather than addressing a 
discrete safety hazard. Equipment manufacturers routinely provide 
gauges in the equipment operator's compartment that indicate engine 
faults. Equipment operators will be alerted by this warning system and 
will then be able to shut the engine down, if appropriate. For these 
reasons, the proposed requirement for automatic engine shutdown based 
on engine compartment temperature has not been adopted in the final 
rule.
    Paragraph (a)(5) requires that guarding be provided to protect 
fuel, hydraulic, and electric lines when such lines pass near rotating 
parts and to protect the lines in the event of shaft failure. This 
requirement is intended to prevent leaks and short circuits caused by 
fuel, hydraulic, and electric lines abrading against rotating parts. 
Rotating parts include machine components such as pulleys, belts, fans, 
and shafts. This requirement is similar to that of the proposal, 
although the proposed rule had specified that ``adequate guarding'' be 
provided and did not include protection for hydraulic lines or 
protection in case of shaft failure. The word ``adequate'' is redundant 
in this context and has not been adopted in the final rule. The 
reference to ``hydraulic lines'' was not included in the proposal 
because no hydraulic systems were permitted on the limited class of 
equipment for which the requirement was proposed. Under the final rule 
these requirements apply to larger equipment with hydraulic systems, 
and protection for hydraulic lines has therefore been added. Guarding 
to protect against shaft failure has also been added to the final rule 
to address the design features of the larger equipment now governed by 
these requirements. MSHA has received reports of several fires ignited 
by broken shafts that damaged hydraulic and electrical lines.
    One commenter supported this requirement, while another commenter 
believed that it was unnecessary. A third commenter recommended that 
the engine compartment be shielded by metal from hydraulic components. 
Protection for fuel, hydraulic, and electrical lines is an essential 
element in preventing fires. The final rule does not specify what 
method must be used to comply with this requirement, because a number 
of different methods, including guarding, shielding as recommended by 
the commenter, or relocation of fuel, hydraulic or electrical lines, 
can provide adequate protection.
    Paragraph (a)(6) has been added to the final rule and requires that 
hydraulic tanks, fillers, vents, and lines be located so that any 
spillage or leaks will not contact hot surfaces. This requirement has 
been added to the final rule to supplement the guarding of hydraulic 
lines in paragraph (a)(5) and is supported by the Ontario fire accident 
data, which show that leaking hydraulic lines contribute to fires. This 
requirement was not included in the proposal because, as explained in 
the discussion of paragraph (a)(5), hydraulic systems would not have 
been permitted on the limited class of light-duty equipment to which 
the requirement would have applied under the proposal. This requirement 
will ensure that spills and leaks of combustible hydraulic fluid do not 
contact hot equipment surfaces. This requirement can be satisfied by 
relocation of machine components, or by directing spills and leaks away 
from hot surfaces by means of splash guards or other such devices.
    Paragraph (a)(7) requires that reflectors or warning lights which 
can be readily seen in all directions be mounted on equipment. This 
requirement was generally supported by commenters and is adopted 
unchanged from the proposal. A determination of whether the reflectors 
or warning lights can be ``readily seen'' must be based on the unique 
mine conditions, and must take into account such things as equipment 
size in relation to the mine entry and undulating mine terrain.
    Paragraph (a)(8) has been added to the final rule in response to 
comments, and requires that a means be installed on the equipment to 
direct exhaust gas away from the equipment operator and persons on 
board the machine. This requirement is intended to provide for the 
discharge of exhaust gases away from persons on the machine to the 
greatest extent practicable, minimizing their exposure to excessive 
levels of unhealthful diesel exhaust contaminants. The exhaust pipe 
must direct the flow away from any area where a machine operator or a 
passenger could be located. Exhaust pipes that extend straight up and 
that would allow the exhaust to flow back over the equipment operator 
as the machine moves forward, such as on some agricultural and 
commercial equipment, are unacceptable under the final rule. This 
requirement is added to the final rule in response to the 
recommendation of two commenters, one of whom noted that exhaust gases 
can build up in the operator's compartment of a machine.
    Paragraph (a)(9) has been added to the final rule in response to a 
commenter and as a result of the expansion of the class of equipment 
subject to the requirements of this section. This paragraph requires 
that a means be provided to prevent unintentional free and uncontrolled 
descent of personnel-elevating work platforms. Personnel-elevating work 
platforms normally are equipped with hydraulic systems and would 
consequently not have been eligible for inclusion in the category of 
limited class equipment under the proposed rule. This requirement is 
currently applied to equipment approved under existing part 36. 
Hydraulically operated personnel-elevating platforms meeting the 
applicable American National Standards Institute criteria for 
personnel-elevating platforms (i.e., ANSI A92.2 and A.92.5) would be 
acceptable. This requirement also applies to work platforms which 
utilize other methods to raise the platform, such as wire ropes. The 
machine must be provided with a specific feature that prevents the free 
and uncontrolled descent of the platform in the event of a failure in 
the lifting system, such as a ruptured hydraulic hose or broken wire 
rope. In such a situation, the platform must descend at a rate which 
will not endanger miners located on or below the platform.
    Paragraph (a)(10) has been added to the final rule and requires 
that all nonpermissible equipment be provided with a means to prevent 
the spray from ruptured hydraulic or lubricating oil lines from being 
ignited by contact with engine exhaust system component surfaces. This 
requirement achieves the goal of the limitation of surface temperatures 
in proposed subpart G of part 7, which is not adopted in the final 
rule, and recognizes that high surface temperatures on diesel-powered 
equipment can be controlled in ways other than the water-jacketing of 
hot engine components contemplated under proposed subpart G. The 
requirement of this paragraph, in conjunction with other requirements 
in the final rule for control of fuel sources on diesel-powered 
machines, will provide effective fire prevention on nonpermissible 
diesel-powered equipment used underground.
    The requirements of this paragraph are performance-oriented, and 
are

[[Page 55466]]

intended not only to allow flexibility in compliance but also to 
accommodate new technology developed in the future. One method of 
achieving compliance with this requirement is through the use of a 
water-cooled manifold. A safety component system certified under part 
36 or a power package approved under subpart F of part 7 of the final 
rule also satisfies the requirement of this paragraph.
    Non-absorbent insulating materials are also available for use on 
mining equipment to reduce the surface temperature of diesel exhaust 
system components. Such materials, which were first developed for 
diesel-powered military vehicles, are impervious to hydraulic fluid, 
lubricating fluids, and diesel fuel, and have been successfully used on 
mining equipment in the United States and Canada. Use of these 
materials can reduce surface temperatures of exhaust components to less 
than 300  deg.F, and may also be used to prevent contact of hydraulic 
fluid and lubricating oil with hot surfaces. The goal of applying the 
insulating material is to substantially reduce the surface area of the 
exhaust system that is at elevated temperatures, because of the direct 
relationship between the area of a hot surface and the likelihood of 
ignition of a spray of hydraulic fluid. A large area of exhaust 
component, which includes the turbocharger, at a high temperature is 
more likely to ignite a spray.
    The use of shielding or partitions to isolate hydraulic components 
from the engine would also satisfy the requirement of this paragraph, 
preventing the fluid from contacting the engine in the event of a leak. 
One commenter retrofitted a diesel-powered machine to provide shielding 
of the engine.
    Paragraph (b) sets forth additional requirements for self-propelled 
nonpermissible diesel-powered equipment, which are specifically 
designed for equipment that moves under its own power, as opposed to 
equipment that is towed. Paragraph (b)(1) has been added to the final 
rule and requires a means to ensure that no stored hydraulic energy 
that will cause machine articulation is available after the engine is 
shut down. As discussed elsewhere in the preamble, requirements 
relating to hydraulic systems were not included in the proposal because 
the affected equipment could not have hydraulic systems. This 
requirement is intended to eliminate accidents where an equipment 
operator inadvertently activates the steering controls on articulated 
vehicles when entering or exiting the operator's compartment. In many 
articulated machine designs, personnel must enter the equipment 
operator's compartment through the articulation area. If the 
articulation joint were to close as the operator entered the 
compartment, the operator could be crushed. This requirement will also 
protect miners who encounter a machine that has been shut down and who 
may accidentally activate the control levers. Under the final rule, the 
stored hydraulic energy does not have to be dissipated instantly. The 
time permitted for dissipation of the stored energy will depend on the 
machine design and the amount of movement the machine is capable of 
after shutdown.
    Paragraph (b)(2) has been added to the final rule in response to a 
specific comment that equipment should only be able to start in 
neutral. This paragraph requires equipment to be provided with a 
neutral start feature which ensures that engine cranking torque will 
not be transmitted through the powertrain and cause machine movement on 
vehicles utilizing fluid power transmissions. MSHA agrees with the 
commenter that this requirement is necessary, because some types of 
diesel-powered equipment may be started with the transmission in gear. 
This could result in power being delivered to the driving wheels of the 
machine before the equipment operator is in control of the vehicle, 
endangering both the operator and miners working in the vicinity of the 
equipment. Equipment must be designed such that its transmission is in 
either neutral or park before the starter will crank the engine.
    For machines with steering wheels, brake pedals, and accelerator 
pedals, paragraph (b)(3) requires that the controls be arranged 
consistent with standard automobile orientation. This requirement has 
been added in response to a commenter who was concerned that equipment 
operators could become confused in the operation of equipment controls. 
Under this paragraph the brake pedal must be on the left and the 
accelerator must be on the right when the operator is facing the 
controls. Clockwise rotation of the steering wheel must turn the 
machine to the right, and counter-clockwise rotation of the steering 
wheel must turn the machine to the left. For machines with seating 
perpendicular to the direction of travel, the forward direction of 
travel and the automobile orientation of the controls are to be defined 
with respect to the front end of the equipment. For machines where the 
operator changes seats depending on the direction of travel, the 
machine control movements should also change accordingly, to retain the 
automobile orientation.
    Paragraph (b)(4), like the proposal, requires self-propelled 
equipment to be provided with an audible warning device conveniently 
located near the operator. Such a device could be a horn or bell, and 
must be capable of being heard over the operation of the machine by 
miners in the area. Commenters were generally supportive of this 
provision.
    Paragraph (b)(5) requires that lights be provided and maintained on 
both ends of the equipment. Equipment normally operated in both 
directions must be equipped with headlights for both directions. The 
proposal would have required self-propelled equipment to be provided 
with headlights, tail lights, and back-up lights. The requirement in 
the final rule is derived from the proposal but has been revised to 
better address typical lighting configurations on all types of 
nonpermissible equipment, not only the limited class of equipment that 
would have been affected under the proposal. For equipment such as 
ramcars, headlights on each end of the machine would be required, but 
not tail lights or back-up lights. For pickup trucks, headlights and 
back-up lights installed as original equipment would satisfy this 
requirement. The lights required by this paragraph are in addition to 
the warning lights or reflectors required by paragraph (a)(7) of this 
section.
    Under the proposal lights would have been required to be 
``protected from accidental damage''. The final rule requires instead 
that lights be ``maintained'', in response to a commenter who 
questioned what was meant by ``protected from accidental damage.'' 
Under the final rule equipment lights must be kept in working order, 
and replaced if they burn out or are damaged.
    Although most commenters generally agreed with the proposed 
requirement, one commenter supported a requirement for back-up alarms 
or other means to alert miners to a change in the direction that 
equipment is moving. Although a back-up alarm may be appropriate on 
some equipment, an alarm on equipment that normally operates in both 
directions is not advisable because the alarm would be set off on a 
regular basis, defeating its effectiveness as a warning system. This 
suggestion has therefore not been adopted in the final rule.
    Paragraph (b)(5) also requires equipment that normally operates in 
both directions to be equipped with headlights for both directions. One 
commenter recommended that lights be designed for operation in both

[[Page 55467]]

directions at once. This commenter noted that normally the light switch 
allows the lights to be on in only one direction and that it would be 
beneficial to observe the load while traveling in the other direction. 
Although this feature may be appropriate under some circumstances, it 
would provide no significant safety benefit and is not warranted for 
inclusion as a general machine feature. In many mines, the fact that 
lights are illuminated in only one direction at a time allows other 
miners in the vicinity to determine the equipment's direction of 
movement and provides some safety benefit. Illumination of both sets of 
lights at the same time would eliminate this capability, and this 
suggestion has therefore not been adopted in the final rule.
    Paragraph (b)(6) requires that self-propelled nonpermissible 
equipment be provided with service brakes that act on each wheel of the 
vehicle and that are designed such that failure of any single 
component, except the brake pedal or similar actuation device, does not 
result in a complete loss of service braking capability. This paragraph 
requires two separate brake systems and ensures that, in the event of 
the failure of one braking system, the other system can bring the 
machine to a controlled stop. The only common component permitted in 
the two systems is the brake pedal or a similar device, such as a lever 
or button that is actuated by the equipment operator. This requirement 
has been adopted from the proposal with slight revisions to specify 
that the service brakes ``act on each wheel'' instead of ``for each 
wheel''. This will allow the use of axle brakes, which act on all of 
the wheels on that axle. This requirement prohibits drive line brakes 
in which failure of a single drive shaft or chain results in the loss 
of all braking capability. A split brake system with two completely 
independent hydraulic circuits with an automotive-type dual piston 
master cylinder complies with this requirement.
    The proposal provided that failure of one ``brake line'' must not 
result in a complete loss of service braking capability. This language 
has been changed to provide that failure of any ``single component'' 
must not result in a complete loss of service braking capability, to 
conform the requirement to the expanded range of equipment that is 
governed by this requirement under the final rule.
    The brake pedal or other interface between the equipment operator 
and the braking system is excluded from this requirement. If the pedal 
is connected to more than one link to activate the brake systems, those 
links must provide for independent actuation of the brake systems in 
the event of the failure of one of the links. Drive line brakes are not 
adequate because of the frequent failure of universal joints. The 
failure of the universal joint could result in the loss of all braking 
ability if a second brake system is not provided. Most agricultural 
equipment and some commercial equipment used in mines, such as high 
lifts or backhoes, may need a retrofit of their braking systems to 
comply with this requirement.
    Several commenters supported this requirement and recommended two 
braking systems independent of each other in all working aspects. Other 
commenters noted that a single brake system would be adequate for 
tractor-type vehicles because they travel at speeds of less than 15 
mph. MSHA disagrees that the low speeds of this type of equipment 
eliminates the need for two brake systems. Failure of an equipment's 
brake system in the confined area of an underground coal mine could 
result in serious injury or death, even at speeds of 15 mph or less. 
The final rule therefore does not incorporate this comment. Other 
commenters were of the opinion that the brake systems should not be 
separate for each wheel. This recommendation has been incorporated into 
the language of the final rule.
    Paragraph (b)(7) has been adopted unchanged from the proposal and 
requires self-propelled nonpermissible equipment to be provided with 
service brakes that can safely bring the fully loaded vehicle to a 
complete stop on the maximum grade on which it is operated. No stopping 
distance or braking force is specified in the final rule, to allow 
flexibility in equipment design and usage. Compliance with this 
requirement is highly site-dependent because of the variation in mine 
grades. The mine operator is responsible for ensuring that equipment 
with adequate grade-holding ability is used at a particular location. 
Commenters generally supported this requirement.
    Paragraph (b)(8) has been added to the final rule and requires that 
no device that traps a column of fluid to hold the brake in the applied 
position be installed in any brake system, unless the trapped column of 
fluid is released when the operator is no longer in contact with the 
brake activation device. This requirement prohibits the installation of 
``park'' brakes devices which rely on a trapped column of fluid, and 
has been included in response to the suggestion of commenters. The use 
of such devices can present serious hazards, and are prohibited. 
Because the temperature of hydraulic brake fluid increases due to 
usage, a column of fluid trapped at a sufficient pressure will 
initially apply the brakes sufficiently to hold the machine stationary. 
However, as the fluid cools it contracts, lowering the pressure and 
possibly releasing the brakes. These devices are not permitted even as 
supplemental devices, because of the risk that equipment operators 
would use them as park brakes even if another park brake is provided. 
Several fatal accidents have been attributed to use of these devices, 
also called ``mico lock braking systems''.
    This requirement does not apply to normal automotive-type service 
brakes which trap a column of fluid, as long as the operator is 
applying pressure to the foot pedal. This requirement also does not 
preclude the use of hydrostatic drive wheel motors that are designed 
and maintained to function as service brakes. These wheel motors do not 
necessarily lose their service braking ability if the fluid cools or if 
minimal leakage occurs. The wheel motors can act to maintain continuous 
pressure in the braking circuit. Although hydrostatic wheel motors can 
function as adequate service brakes, these systems do not provide 
adequate parking brake capability. For the wheel motor to maintain 
pressure in the braking circuit, the wheel must turn slightly, thereby 
permitting the machine to move very slowly down the grade. This 
movement is insignificant during the short period of time the service 
brakes are applied. However, if wheel motors are used as parking 
brakes, the machine can move a significant distance when the equipment 
operator is away from the machine. This can endanger miners who may be 
working near the machine in the confined area of the mine.
    Paragraph (c) has been added to this section of the final rule to 
specifically address self-propelled nonpermissible heavy-duty diesel-
powered equipment meeting the requirements of Sec. 75.1908(a), except 
rail-mounted equipment. These requirements have been added to the final 
rule in response to the additional types of equipment that are now 
subject to the requirements of this section. Heavy-duty equipment that 
hauls rock, coal, or longwall components or transports large quantities 
of diesel fuel are governed by these safety requirements, and must be 
provided with a supplemental braking system that meets specified 
criteria. The criteria for these braking systems were developed from 
the criteria contained in Sec. 75.523-3, applicable to automatic 
emergency parking brakes on similar

[[Page 55468]]

types of electrical equipment. There was widespread support for 
applying these braking requirements to diesel-powered equipment, in 
comments submitted in response to the advance notice of proposed 
rulemaking addressing equipment approval and machine safety features. 
Although there was a difference of opinion among these commenters as 
far as whether these braking requirements should be incorporated as 
part of an equipment approval program, commenters did agree that they 
be included as machine features either in an approval program or as 
mandatory safety standards in part 75. Commenters also recommended that 
there should be separate brake requirements for rail-mounted equipment. 
The Agency agrees with these comments, and has concluded that existing 
brake requirements in Secs. 75.1404 and 75.1404-1, which apply to both 
electric and diesel-powered rail-mounted equipment, provide sufficient 
protection. Rail-mounted equipment has therefore been specifically 
excluded from this requirement under the final rule.
    Existing Sec. 75.523-3 specifies different requirements for two 
types of electric-powered equipment: haulage equipment and all other 
equipment. Electric-powered haulage equipment is very similar in 
function to the heavy-duty diesel-powered equipment subject to this 
requirement. Paragraphs (c)(1) through (c)(5) of this section of the 
final rule closely track the brake system requirements for electric 
haulage equipment in existing Sec. 75.523-3, with the exception of the 
requirement that the brake be engaged by an emergency deenergization 
device or panic bar. A panic bar is appropriate for only some types of 
permissible diesel-powered equipment, and will be addressed during the 
part 36 approval process. Panic bars are not required for 
nonpermissible diesel-powered equipment. Under the final rule, self-
propelled nonpermissible heavy-duty diesel-powered equipment, except 
rail-mounted equipment, is required to have a supplemental braking 
system that: (1) Engages automatically within 5 seconds of shutdown of 
the engine; (2) safely brings the equipment when fully loaded to a 
complete stop on the maximum grade where it is operated; (3) holds the 
equipment stationary, despite any contraction of brake parts, 
exhaustion of any nonmechanical source of energy, or leakage; (4) 
releases only by a manual control that does not operate any equipment 
function; (5) has a means in the equipment operator's compartment to 
apply the brakes manually without the engine operating, and a means to 
release and reengage the brakes without the engine operating; and (6) 
has a means to ensure that the supplemental braking system is released 
before the equipment can be trammed, and is designed to ensure that the 
brake is fully released at all times when the equipment is trammed.
    Paragraph (c)(6) has been added to the final rule and requires that 
the supplemental braking system have a means to ensure that the system 
is released before the equipment can be trammed. It further requires 
that the system be designed to ensure the brake is fully released at 
all times while the equipment is trammed. This requirement is added to 
the final rule to address the hazard of dragging brakes, which were the 
cause of numerous fires reported in the Ontario fire data analyzed by 
MSHA in response to a commenter's recommendation. Some manufacturers 
install a lever on the transmission gear selector to ensure that the 
supplemental brakes are released. This lever automatically releases the 
brake when the operator shifts the transmission into gear.
    Paragraph (d) applies to self-propelled nonpermissible light-duty 
diesel-powered equipment meeting the requirements of Sec. 75.1908(b), 
except rail-mounted equipment. This provision, which has been adopted 
from the proposal, requires that the equipment be provided with a 
parking brake that holds the fully loaded equipment stationary on the 
maximum grade on which it is operated despite any contraction of the 
brake parts, exhaustion of any nonmechanical source of energy or 
leakage. This requirement was developed from existing Sec. 75.523-3(d), 
which addresses parking brakes for electric-powered equipment other 
than haulage equipment, which is similar to the equipment in the light-
duty category under Sec. 75.1908(b) of the final rule.
    A parking brake meeting the requirements of paragraph (d), rather 
than the supplemental brake system required for heavy-duty equipment 
under paragraph (c), is adequate for light-duty equipment, which is 
typically used for transportation or moving of supplies on an 
intermittent basis.
    Paragraph (e) has been added to the final rule as a result of the 
inclusion of requirements for supplemental and park brake systems under 
paragraphs (c) and (d) of this section. This paragraph requires that 
the supplemental and park brake systems required by paragraphs (c) and 
(d) be applied when the equipment operator is not at the controls of 
the equipment, except during movement of disabled equipment. This 
requirement was developed from existing Sec. 75.523-3(e), and requires 
the machine operator to set the brakes when not at the controls. 
However, this provision is not intended to suggest that it would be a 
safe practice for the operator to apply the brake and leave the machine 
with the engine running.
    Paragraph (f) has been added to the final rule as a result of 
MSHA's review of the Ontario fire data, and requires self-propelled 
personnel-elevating work platforms be provided with a means to ensure 
that the parking braking system is released before the equipment can be 
trammed, and that the platforms be designed to ensure the brake is 
fully released at all times while the equipment is trammed. MSHA's 
review of the Ontario fire data revealed a high number of personnel-
elevating vehicle fires caused by dragging brakes. The final rule 
applies the same requirement to personnel-elevating vehicles in this 
paragraph as applies to self-propelled heavy-duty nonpermissible 
equipment under paragraph (c)(6).
    Paragraph (g) has been added to the final rule and requires that 
any nonpermissible equipment that discharges its exhaust directly into 
a return air course be provided with a power package approved under 
subpart F of part 7. The basis for this requirement is the possibility 
that the return air course may contain high levels of methane, which 
could be drawn into the machine's exhaust system as it cools after 
engine shutdown. This creates the potential for ignition of the methane 
by the hot surfaces of the diesel engine. As a result, the final rule 
requires equipment which discharges its exhaust directly into the 
return to be furnished with the fire and explosion protection provided 
by a subpart F power package. Equipment without a subpart F power 
package must discharge its exhaust into intake air.
    Under the proposed rule all nonpermissible equipment, with the 
exception of a limited class of light-duty equipment, would have been 
required to be equipped with a power package approved under either 
subpart F or G of part 7. Subpart F power packages are equipped with 
spark arresters and flame arresters, which significantly reduce the 
likelihood that equipment will ignite explosive levels of methane. 
Because the final rule does not require power packages on 
nonpermissible equipment, this requirement has been added to the final 
rule to ensure that nonpermissible equipment that discharges it exhaust 
directly into a return air course, which could contain explosive levels 
of

[[Page 55469]]

methane, will not create an explosion hazard.
    Paragraph (h) requires that self-propelled nonpermissible heavy-
duty equipment meeting the requirements of Sec. 75.1908(a) be provided 
with an automatic fire suppression system meeting the requirements of 
Sec. 75.1911. Paragraph (i) requires that self-propelled nonpermissible 
light-duty equipment meeting the requirements of Sec. 75.1908(b) be 
provided with a manual or automatic fire suppression system meeting the 
requirements of Sec. 75.1911. Under the proposed rule, all 
nonpermissible equipment would have been required to be provided with 
an automatic fire suppression system.
    As explained in greater detail in the preamble discussion for 
Sec. 75.1911 of the final rule, some commenters supported automatic 
fire suppression systems for all types of equipment, while others 
expressed support for automatic fire suppression systems on portable or 
unattended equipment but were strongly opposed to requiring automatic 
fire suppression on all types of nonpermissible diesel-powered 
equipment. These commenters stated that automatic fire suppression 
systems were much more difficult to maintain, and were unnecessary for 
equipment that was attended by an equipment operator. These commenters 
suggested that mine operators should have the option of installing 
either manual or automatic systems on self-propelled equipment, stating 
that the equipment operator is in the best position to detect machine 
fires, and would be able to actuate a manual fire suppression system 
more easily than an automatic system. Other commenters stated that it 
might be difficult for an equipment operator to actuate a manual system 
depending on the size and type of the fire, expressing concern that an 
equipment operator could be overcome by the effects of a fire or 
explosion and not be able to manually extinguish the fire.
    As discussed more fully under Sec. 75.1911 of the preamble, the 
Ontario fire accident data indicates that heavy-duty diesel-powered 
equipment, such as the type specified in Sec. 75.1908(a) of the final 
rule, presents a much greater fire hazard than light-duty equipment. 
Although light-duty equipment still presents some fire risk, a 
manually-actuated fire suppression system provides adequate protection 
if the equipment is attended and provided with additional safety 
features for protection of fuel, hydraulic, and electrical systems 
under this section and Sec. 75.1910 of the final rule. As noted 
elsewhere in this preamble, Sec. 75.1916(d) of the final rule requires 
all diesel-powered equipment to be attended while it is being operated.
    An automatic fire suppression system is needed on equipment that 
presents a greater fire risk. Good fire fighting practice demands that 
a fire be suppressed as early as possible, and several reports of fire 
indicate that the rapid growth of a fire prevented the equipment 
operator from actuating the manual fire suppression system. Automatic 
systems respond quickly to fire without operator intervention, and are 
needed on equipment that operates frequently for long periods of time 
under high load, presenting an increased fire risk. Compressors and 
other non-self-propelled equipment also operate for long periods of 
time under high load. This results not only in high engine temperatures 
but also increases the possibility of mechanical failure, presenting 
ignition and fuel sources. To address these hazards, automatic fire 
suppression systems meeting the requirements of Sec. 75.1911 of the 
final rule are required under paragraph (h) for self-propelled heavy-
duty nonpermissible equipment, and under paragraph (j)(3) for both 
heavy-duty and light-duty equipment that is not self- propelled. 
Paragraph (i) provides that self-propelled light-duty nonpermissible 
equipment may be provided with either a manual or an automatic system 
that meets the requirements of Sec. 75.1911.
    Paragraph (j) requires nonpermissible diesel-powered equipment that 
is not self-propelled to be provided with features in addition to those 
listed in paragraph (a). These features include a means to prevent 
inadvertent movement of the equipment when parked, safety chains or 
other suitable secondary connections on equipment that is being towed, 
and, as discussed above, an automatic fire suppression system meeting 
the requirements of Sec. 75.1911. A requirement for automatic fire 
suppression for non-self-propelled equipment has been retained in the 
final rule in recognition of the fact that non-self-propelled equipment 
is typically operated under load for extended periods of time, 
resulting in the need for automatic rather than manual fire suppression 
to address the additional fire risks. MSHA intends that automatic fire 
suppression systems be provided for those machines, such as 
compressors, welders, and generators, that may have some limited 
capacity for self- propulsion but which essentially function as 
portable equipment, i.e., where the equipment operator performs a 
function some distance from the machine while the equipment is running.
    The proposal would have required a means to prevent inadvertent 
movement as well as safety chains or other connections for equipment 
being towed, but would have required a fire extinguisher instead of an 
automatic fire suppression system. The proposal would also have 
required the equipment to be provided with a sensor to monitor 
equipment operation that would stop the engine when an equipment 
malfunction would result in the creation of a hazard.
    The proposed requirement for sensors to monitor the operation of 
portable equipment has not been adopted in the final rule. Several 
commenters expressed confusion as to what these devices were intended 
to monitor, and suggested that this requirement be eliminated because 
it was vague and ambiguous. The proposed requirement was intended to 
ensure that general safety devices supplied as original equipment 
features, such as low oil sensors or high temperature sensors, were 
maintained in proper working condition. However, MSHA has concluded 
that it would be extremely difficult to develop a standard that is any 
more specific than what was proposed that would be suitable for the 
variety of monitors and sensors that may be installed on equipment. In 
light of these circumstances, and in light of the fact that all 
equipment used in underground coal mines is required to be maintained 
in safe operating condition under existing Sec. 75.1725, this 
requirement has not been adopted in the final rule.
    A number of commenters recommended that additional equipment safety 
features be required in the final rule that were not included in the 
proposal. Several commenters expressed concern about limited visibility 
from the operator's compartment on certain types of large diesel-
powered equipment. The final rule does not adopt these commenters' 
recommendations. Although this concern is addressed to some extent by 
Sec. 75.1916 of the final rule, which requires that mines using diesel-
powered equipment establish and follow standardized traffic rules, MSHA 
has concluded that the issue of operator equipment design and 
visibility should be addressed in the context of all types of 
equipment, not only diesel-powered equipment. Specific provisions on 
operator visibility have therefore not been included in the final rule.

[[Page 55470]]

Section 75.1910  Nonpermissible Diesel-Powered Equipment; Electrical 
System Design and Performance Requirements
    This section addresses electrical system requirements for 
nonpermissible diesel-powered equipment. These requirements were 
proposed in Sec. 75.1909 with other equipment safety requirements that 
would have applied to a limited class of nonpermissible light-duty 
equipment, but in the final rule are included separately in 
Sec. 75.1910.
    Faulty equipment electrical systems have frequently been the cause 
of equipment fires, and the requirements of this section address the 
hazards associated with these systems. Although commenters generally 
supported the proposed requirements, one commenter suggested that these 
requirements not be adopted in the final rule, because some equipment 
is designed for highway use and meets safety standards that have been 
developed by the industry over many years. The commenter asserted that 
changing the design of those machines' electrical systems would have an 
adverse impact on machine safety. MSHA is aware that electrical systems 
on certain types of diesel-powered equipment, such as utility vehicles, 
personnel carriers, and ambulances, are designed to meet safety 
standards for highway use. However, this final rule expands the scope 
of the limited class of equipment to include types of equipment that 
would not meet the requirements for highway use. Additionally, because 
of the significant hazards presented by a fire in an underground mine, 
additional safeguards for electrical systems on equipment employing 
storage batteries and integral charging systems are warranted, given 
the fact that a number of electrical accidents have been attributed to 
faults in these systems. The analysis of the Ontario fire accident data 
revealed that 43 percent of the fires were attributable to electrical 
system faults. Almost half of these were related to the engine starting 
and charging systems. Changes in machine design to comply with the 
requirements in this section are necessary to enhance safety. For these 
reasons, the final rule retains these special provisions.
    The requirements included under this section of the final rule 
apply only to those electrical circuits and components associated with, 
or connected to, electrical systems utilizing storage batteries and 
integral charging systems. It should be noted, as indicated in the rule 
itself, that these requirements do not apply to equipment that falls 
within the special category of emergency equipment under 
Sec. 75.1908(d) of the final rule. The requirements in this section 
would apply, for example, to circuits for instrument panel gages and 
machine lights on most equipment utilizing storage batteries and 
integral charging systems. Accordingly, electrical systems on 
nonpermissible diesel-powered equipment without storage batteries and 
charging systems are not governed by the requirements of this section. 
Additionally, the requirements of this section do not apply to 
electrical circuits and components on equipment that is not directly 
connected to or otherwise powered from a separate electrical system 
utilizing storage batteries and an integral charging system. Both types 
of systems should be designed and maintained in compliance with 
existing safety standards in part 75 for underground coal mines.
    Several commenters suggested that the proposed electrical system 
requirements not be adopted in the final rule, and instead that the 
final rule provide that electrical systems on diesel-powered equipment 
comply with existing part 75 electrical safety standards for 
nonpermissible equipment. Some of these commenters also suggested that 
more performance-oriented standards be developed for electrical 
circuits and components associated with storage batteries and charging 
systems.
    Performance-oriented requirements have been adopted where 
appropriate in the final rule to allow flexibility in design and to 
facilitate future development of new and improved technology. Instead 
of simply applying existing requirements to this equipment, as 
suggested by some commenters, many of the requirements of this section 
have been derived from existing MSHA electrical safety standards in 
part 75 but have been tailored to apply to diesel-powered equipment.
    It should be noted that MSHA does not consider the continuous on-
board recharging of the battery on this equipment, which typically 
power auxiliary features such as headlights, to be the type of battery-
charging contemplated by existing Sec. 75.340.
    Paragraph (a) addresses overload and short circuit protection of 
electric circuits and components and, like the proposal, requires that 
such protection be provided in accordance with existing Secs. 75.518 
and 75.518-1. The references to the existing sections have been 
retained in the final rule in response to commenters' suggestions that 
such references would minimize confusion over what the standard 
requires.
    Paragraphs (b) and (c) are adopted from the proposal and were 
developed from existing approval requirements for electrical systems on 
other types of diesel-powered equipment. Paragraph (b) requires that 
each electric conductor from the battery to the starting motor be 
provided with short circuit protection, and requires that the short 
circuit protective device be placed as near as practicable to the 
battery terminals. Paragraph (c) requires that each branch circuit 
conductor connected to the main circuit between the battery and the 
charging generator be provided with circuit protection. When complied 
with, these requirements will provide all electric conductors and 
circuits with circuit protection and will minimize the hazards of fire 
due to circuit failure.
    Paragraph (d), like the proposal, requires that a main circuit-
interrupting device be provided in the electrical system so that power 
may be disconnected from the equipment, at or near the battery 
terminals, in the event of an emergency. The device must be located as 
close as practicable to the battery terminals and be designed to 
operate within its electrical rating without damage. This paragraph 
also requires that the device not automatically reset after being 
actuated, and that magnetic devices be mounted in such a manner to 
preclude closing by gravity. This requirement reduces the possibility 
of a fire in the event of a short circuit protective device 
malfunction. The proposal would have provided that a manually operated 
controller, such as a rheostat, would not be acceptable as a service 
switch. This provision has not been included in the final rule because 
it is redundant and adds nothing of substance to the paragraph. 
Manually operated controllers are not typically used on diesel-powered 
equipment, and would be prohibited in any case by the language in the 
final rule.
    Under the final rule circuit-interrupting devices must be designed 
not to automatically reset after being actuated. If the circuit has 
been interrupted it is most likely due to some fault in the system, and 
an automatic reset would defeat the purpose behind the device. These 
devices must also be operational within their electrical rating without 
damage, because otherwise they could self-destruct. Magnetic circuit-
interrupting devices are required to be mounted in a manner that 
prevents gravity from closing the contacts to prevent a premature or 
undesirable activation of electric circuits. The requirements of this 
paragraph ensure proper design and installation of circuit-interrupting 
devices.

[[Page 55471]]

    The proposed rule would have included the additional requirement 
that circuit-interrupting devices and other controls be designed so 
that they could be operated without opening any compartment in which 
they were enclosed. This proposed provision has not been adopted in the 
final rule, in response to commenters who advocated performance-
oriented requirements. The proposal would also have required that 
circuit-interrupting devices meet the requirements of existing 
Sec. 75.520, which simply requires that all electric equipment be 
provided with switches or other controls that are safely designed, 
constructed, and installed. This reference adds little or nothing of 
substance to the requirements of this paragraph, and has not been 
adopted in the final rule.
    Paragraph (e) adopts the proposed requirement that each motor and 
charging generator be protected from overload by an automatic 
overcurrent device. This requirement is necessary to ensure proper 
deenergization of circuits and equipment in the event of overcurrent 
conditions such as arcing and motor overheating, and, when complied 
with, will minimize resulting fire hazards. The final rule also adopts 
the proposed provision that one device will be acceptable when two 
motors of the same rating operate simultaneously and perform virtually 
the same duty.
    The requirements of paragraph (f), like the proposal, address 
conductor size and capacity. Proper selection of circuit conductors of 
adequate size and current carrying capacity and with insulation 
compatible with the circuit voltage depends on the environmental 
conditions under which the conductors will be used. Conductor size and 
capacity are also important in minimizing overload and short circuit 
conditions which could cause a fire. The final rule adopts the proposed 
requirements that each ungrounded conductor have insulation compatible 
with the impressed voltage, and that insulation materials be resistant 
to deterioration from engine heat and oil. The final rule, like the 
proposal, also requires that electric conductors meet the requirements 
of existing Secs. 75.513 and 75.513-1, except for electrical conductors 
for starting motors, which must only comply with the performance-
oriented requirements of Sec. 75.513. Existing Sec. 75.513 provides 
that all electric conductors shall be sufficient in size and have 
adequate current carrying capacity and be of such construction that a 
rise in temperature resulting from normal operation will not damage the 
insulating material. Existing Sec. 75.513-1 provides that an electric 
conductor is not of sufficient size to have adequate current carrying 
capacity if it is smaller than provided for in the National Electric 
Code of 1968.
    Existing Secs. 75.513 and 75.513-1 were developed for electrical 
equipment used in outby locations, but they are also suitable for 
application to all nonpermissible diesel- powered equipment. Greater 
flexibility is provided for electric conductors for starting motors, 
which are not required to meet the size and carrying capacity 
requirements under Sec. 75.513-1, but must only comply with the 
performance requirements of Sec. 75.513. This is because the conductor 
size requirements in the 1968 National Electric Code are determined 
based on the motor running at maximum load, with no allowance for the 
type of duty. The conductor sizes specified in the Code would therefore 
not be appropriate for starting motors, which typically run for only a 
very short period of time.
    Several commenters objected to the requirement in the proposed rule 
that conductors for equipment or accessories added to a vehicle's 
electrical system after manufacture not be smaller than No. 14 AWG in 
size, stating that some components were not readily available with wire 
sizes compatible with this requirement. In response to this comment and 
in light of the requirements that have been adopted in the final rule, 
which will provide adequate protection, the proposed size restriction 
on certain conductors is not adopted in the final rule.
    Since damaged or defective conductors or components may present 
potential fire hazards, paragraphs (g) and (h) address the protection 
of electric circuits and components. Paragraph (g), like the proposal, 
requires all wiring to have adequate mechanical protection to prevent 
damage to the cable that might result in short circuits. Paragraph (h) 
adopts the proposed requirement that sharp edges and corners be removed 
at all points where there is a possibility for damaging wires, cables, 
or conduits by cutting or abrasion. The insulation of the cables within 
a battery box is also required to be protected against abrasion. These 
paragraphs ensure that circuits are physically protected and secured 
from movement or displacement caused by vibration, as well as from 
cutting or abrasion. The proposed rule would have included the 
additional requirements that wiring have adequate electrical protection 
to prevent cable damage, and that wiring be installed in accordance 
with existing Sec. 75.515, as applicable. The reference to electrical 
protection in the proposal was determined to be redundant, and has not 
been adopted in the final rule. The reference to existing Sec. 75.515 
in the proposal has also not been adopted in the final rule, because it 
simply restates requirements already included in the final rule.
    Paragraph (i) requires electrical connections and splices to be 
electrically and mechanically efficient, in addition to having adequate 
insulating properties. Insulating material would be required in 
applications where space is limited and where the possibility exists of 
arcs striking metal walls or parts. These precautions minimize fire 
hazards from improper or loose connections and splices as well as 
insufficient electrical clearances, which could cause a fire due to 
conductor overheating or electrical arcing. In response to comments, 
specific references to bolted connectors and to existing Sec. 75.514 
have been deleted and replaced with more performance-oriented 
requirements.
    Paragraph (j) of the final rule, like the proposal, requires 
storage batteries to be secured in place to prevent undue movement and 
protected from external damage. Batteries not protected from damage by 
their location on the equipment are required to be housed in a battery 
box.
    Paragraphs (k) through (o) of the final rule set forth requirements 
for battery box construction, and are adopted from the proposal with 
slight revision. These requirements provide for a substantially 
constructed battery enclosure and address battery insulation, 
ventilation, and chemical reaction from electrolyte. A number of 
commenters suggested that more performance-oriented requirements be 
adopted for battery box construction. However, the proposed design 
specifications have been retained in the final rule because they set 
forth the minimum construction requirements needed to protect a battery 
from external damage. One commenter related an incident where a battery 
case had deteriorated, resulting in arcing and sparking between the 
battery terminal and the frame of the machine. Other reports of fires 
from the Ontario fire accident data indicate that a number of fires had 
been caused by batteries that were not secured in place or adequately 
protected from external damage. The minimum design and construction 
requirements for battery boxes in the final rule are necessary to 
reduce these types of hazards.
    Paragraph (k) provides that the battery box, including the cover, 
must be constructed of steel with a minimum thickness of \1/8\ inch, or 
of a material other than steel that provides equivalent strength. One 
commenter specifically

[[Page 55472]]

cited the proposed \3/16\-inch thickness requirement as an example of 
an unnecessary design requirement. This requirement has been changed to 
\1/8\-inch minimum thickness to conform to existing part 7 requirements 
for battery boxes containing batteries no greater than 1,000 pounds. 
Thinner battery box cross sections would not provide adequate 
protection for the battery and could result in a fire or explosion.
    Paragraph (l) provides that battery-box covers must be lined with a 
flame-resistant insulating material permanently attached to the 
underside of the cover, unless equivalent protection is provided. 
Battery-box covers must also be provided with a means for securing them 
in a closed position. At least \1/2\-inch of air space must be provided 
between the underside of the cover and the top of the battery, 
including terminals. Paragraph (m) requires battery boxes to be 
provided with ventilation openings to prevent the accumulation of 
flammable or toxic gases or vapors within the battery box. The size and 
locations of openings for ventilation must prevent direct access to 
battery terminals. Paragraph (n) requires the battery to be insulated 
from the battery-box walls and supported on insulating materials. 
Insulating materials that may be subject to chemical reaction with 
electrolyte must be treated to resist such action. Finally, paragraph 
(o) requires drainage holes in the bottom of each battery box.
    Stationary unattended diesel-powered equipment. The Diesel Advisory 
Committee recommended that stationary unattended diesel-powered 
equipment be prohibited where permissible electric equipment is 
required, and that stationary unattended equipment used elsewhere in 
the mine be provided with the fire prevention features required for 
electrical installations and mobile diesel-powered equipment. The 
Committee recommended that stationary unattended equipment be equipped 
with specific machine features, such as surface temperature controls, 
an automatically and manually actuated fire suppression system, an 
engine shutdown device, and a means to shut down the engine from the 
surface. The Committee also recommended that stationary unattended 
equipment be housed in a fireproof enclosure ventilated to a return air 
course.
    Section 75.1910 of the proposed rule incorporated the 
recommendations of the Advisory Committee for stationary unattended 
equipment. Specifically, proposed Sec. 75.1910 would have prohibited 
stationary unattended diesel-powered equipment in areas of the mine 
where permissible electric equipment was required or in the primary 
escapeway. Stationary unattended equipment located in other areas of 
the mine would have been required to have a diesel power package 
approved under subpart F or G of part 7. Additional safety features 
were proposed for this equipment, including fuel system requirements, 
limitations on storage of the equipment fuel supply, and a methane 
monitor that would shut down the engine in the presence of 1.0 percent 
concentration of methane.
    A number of commenters were concerned that the proposed rule dealt 
with stationary unattended diesel-powered equipment differently than 
existing standards addressed unattended electrical equipment, and 
imposed unnecessary restrictions. These commenters stated that it was 
excessive to require approved power packages on equipment when the 
equipment is already housed in a noncombustible enclosure, vented to a 
return air course, protected by an automatic fire suppression system, 
and equipped with a device that shuts down the equipment and sounds an 
alarm at an attended surface location. Several commenters stated that 
unattended electric equipment, which they believed presented similar 
ignition sources, was not required to have methane monitors, and that 
such monitors were not necessary, given the outby locations where 
stationary nonpermissible equipment would operate.
    Other commenters favored a complete prohibition of unattended 
diesel equipment in underground coal mines, stating that diesel 
equipment presented too great a fire hazard to allow it to be operated 
unattended, even with the imposition of rigid safety requirements. One 
commenter referred to the 1984 Wilberg Mine disaster, where a fire 
started by an unattended electrical compressor killed 27 miners. In the 
alternative, these commenters recommended that extensive additional 
requirements be imposed on stationary unattended equipment, including a 
requirement that the equipment be permissible, and that the enclosure 
housing the equipment meet a 2-hour fire resistance test.
    One commenter stated that there should be clarification of what 
constitutes ``stationary'' versus ``portable'' equipment. The commenter 
pointed out that some types of equipment, such as compressors, are 
portable because they are capable of being transported by rail or 
otherwise carried, but that the equipment can also be placed in a 
remote location and operated there for an indefinite period of time.
    In considering these comments, MSHA reviewed data to determine the 
types of equipment that would be affected by the proposed requirements 
for stationary unattended equipment. This review revealed that there 
were approximately 200 pieces of equipment that were currently being 
operated either as stationary unattended equipment or as portable 
attended equipment. Equipment such as air compressors, generators, mine 
sealant machines, hydraulic power units, rock dusters, water spray 
units, and welders fell into this category. Water spray units are used 
to wash mining equipment; mine sealant machines apply sealants to 
stoppings or mine surfaces; hydraulic power units are used to operate 
certain special purpose tools; rock dusters are used to apply rock dust 
to mine surfaces; and diesel-powered welders are used where electric 
power is not readily available. An operator must be present to perform 
the main function of all of these types of equipment, i.e., welding, 
rock dusting, etc.
    MSHA's review also revealed that diesel-powered generators are 
typically used to provide electrical power to move equipment with 
electric motors from place to place in the mine. An equipment operator 
is also in attendance when this type of equipment is being used. 
Finally, MSHA's review also indicated that diesel-powered compressors 
are used in a manner similar to hydraulic power units, with an operator 
in attendance, to provide a source of compressed air to operate tools 
such as pneumatic hammers and drills.
    From this review, MSHA has concluded that diesel-powered equipment 
is not commonly operated unattended in a permanent location, but 
instead is operated with a person in close proximity. The final rule 
includes a definition of what constitutes attended diesel-powered 
equipment in Sec. 75.1908, which provides that the equipment must 
either be operated by a miner, or located within 500 feet of a job site 
where a miner is located. Essentially all of the diesel-powered 
equipment currently operated in underground coal mines is ``attended'' 
under the final rule's definition. In light of this determination, and 
also in light of the serious concerns expressed by some commenters 
about the possible fire hazards presented by unattended diesel-powered 
equipment operating underground, Sec. 75.1916(d) of the final rule 
prohibits the operation of unattended diesel-powered equipment in 
underground coal mines.

[[Page 55473]]

Consequently, the proposed requirements addressing the operation of 
stationary unattended diesel-powered equipment are not adopted in the 
final rule.
    As a result of the final rule's prohibition against operation of 
unattended diesel-powered equipment in underground coal mines, 
conforming amendments are necessary to several existing standards, 
primarily to delete unnecessary references to unattended diesel-powered 
equipment. Existing Sec. 75.360 lists the locations where preshift 
examiners must examine for hazardous conditions, test for methane and 
oxygen deficiency, and determine if the air is moving in the proper 
direction. The final rule deletes from these locations the reference in 
Sec. 75.360(b)(7) to ``where unattended diesel equipment is to 
operate.'' Additionally, existing Sec. 75.380(f)(3)(i) included a 
prohibition against operation in the primary escapeway of unattended 
diesel equipment without an automatic fire suppression system. This 
reference is deleted by the final rule.
    Finally, existing Sec. 75.344 deals with the use of air compressors 
underground, including unattended diesel compressors. The final 
ventilation rule that was published in October 1989 made clear that the 
application of the requirements of Sec. 75.344 to diesel compressors 
would be removed when the final rule for diesel equipment was 
promulgated. [54 FR 40950]. The reference to diesel compressors in 
paragraph (d) of Sec. 75.344 is therefore removed by the final rule.
Section 75.1911--Fire Suppression Systems For Diesel-Powered Equipment 
And Fuel Transportation Units
    Section 75.1911 of the final rule establishes requirements for the 
design, installation, and maintenance of fire suppression systems used 
on diesel-powered equipment and fuel transportation units in 
underground coal mines. Under the final rule, both permissible and 
nonpermissible diesel-powered equipment is required to be equipped with 
fire suppression systems. The requirement for installation of fire 
suppression systems on permissible diesel-powered equipment is 
contained in the final rule at Sec. 75.1907(b)(2),and for 
nonpermissible equipment at Sec. 75.1909 (h), (i), and (j)(3). 
Nonpermissible diesel-powered equipment typically includes scoops, 
personnel carriers, and pickup trucks.
    The Diesel Advisory Committee recommended that fire suppression 
systems be required on certain types of diesel-powered equipment, in 
addition to surface temperature controls, to address fire hazards 
created by other machine system malfunctions such as brake components 
overheating, severing of a fuel line or hydraulic line, and electric 
component short-circuiting. The Committee made a number of 
recommendations regarding the application of fire suppression systems 
to specific types of equipment such as nonpermissible equipment, 
limited class equipment, and stationary equipment. The proposed rule 
included design, installation and maintenance requirements for fire 
suppression systems on diesel-powered equipment and fuel transportation 
units. These requirements would have been applicable to approved 
equipment, limited class equipment, and fuel transportation units, both 
self-propelled and towed.
    Commenters to the proposed rule generally accepted the need for 
fire suppression systems on diesel-powered equipment operated in 
underground coal mines. However, comments varied on what the 
requirements for fire suppression systems should be. Some commenters 
recommended that only manufacturer's requirements for design, 
installation and maintenance be used. Other commenters suggested a more 
detailed approach and recommended that the final rule outline specific 
requirements for fire suppression systems.
    Fire suppression systems are necessary on diesel-powered equipment, 
including fuel transportation units, because of the numerous fuel 
sources, including diesel fuel, hydraulic fluid, and combustible 
material, and several potential ignition sources, such as hot exhaust 
components, dragging brakes, and electrical wiring on this type of 
equipment. Accident reports describe machine fires caused by hot 
exhaust components, dragging brakes and shorted electrical components 
igniting diesel fuel, hydraulic fluid, brake fluid, lube oil, and other 
combustible materials, such as electrical insulating material.
    Fire suppression systems are designed to extinguish fires quickly, 
in their incipient stage, and to reach all locations where a fire may 
occur. This is important for diesel-powered equipment because a fire 
must be extinguished quickly before fuel sources can further propagate 
a fire. For example, if a fire is not extinguished at an early stage, 
leaking diesel fuel or hydraulic fluid can fuel a fire and result in an 
increase in the intensity and size of the fire. Also, promptly 
extinguishing a fire prevents reignition through the contact of hot 
surfaces created by the fire with leaked or spilled diesel fuel or 
hydraulic fluid. Fixed fire suppression systems also offer two 
advantages over portable fire extinguishers: fast attack and 
application of the suppressant to difficult-to-reach areas on and under 
diesel machines where fires may occur.
    An automatic fire suppression system uses a supplemental detection 
device to sense an early warning of a fire. The fire detection system, 
which is generally actuated by either smoke or heat, automatically 
sends a signal to the system for the discharge of suppressant agent. 
Manual fire suppression systems require a person to actuate the fire 
suppression system by either pushing a button or throwing a switch to 
discharge the fire suppressant agent to the hazard. Both automatic and 
manual fire suppression systems utilize a network of piping and nozzles 
to allow suppressant agent to be released and distributed directly at a 
predetermined fire hazard.
    Under the final rule, fire suppression systems are required to 
provide fire suppression and, if an automatic system is installed, fire 
detection for the engine, transmission, hydraulic pumps and tanks, fuel 
tanks, exposed brake units, air compressors, battery areas and other 
areas as necessary. The final rule also requires that automatic fire 
suppression systems include audible and visual alarms to warn of fires 
or system faults and automatic engine shutdown in the event of a fire. 
In addition, the final rule requires all fire suppression systems to be 
tested and maintained in accordance with manufacturer's 
recommendations. Finally, the rule establishes certain recordkeeping 
requirements for faulty fire suppression systems that are found during 
inspection and testing.
    Paragraph (a) of this section of the final rule provides that the 
fire suppression system required by Secs. 75.1907 and 75.1909 must be a 
multipurpose dry chemical type (ABC) fire suppression system listed or 
approved by a nationally recognized independent testing laboratory and 
appropriate for installation on diesel-powered equipment and fuel 
transportation units.
    The proposed rule would have required an automatic multipurpose dry 
powder type fire suppression system suitable for its intended 
application and listed or approved by a nationally recognized 
independent testing laboratory on diesel-powered equipment and portable 
diesel-powered equipment and fuel transportation units. The proposal 
would have further established fire suppression requirements for 
approved equipment, limited class equipment, and fuel transportation 
units, both self-propelled and towed.

[[Page 55474]]

    Commenters expressed support for automatic fire suppression systems 
on portable or unattended diesel-powered equipment. A number of 
commenters, however, stated that automatic fire suppression systems are 
not needed on self-propelled diesel-powered equipment, because this 
type of equipment is attended by an equipment operator. These 
commenters suggested that mine operators should have the option of 
providing either manual or automatic fire suppression systems on self-
propelled diesel-powered equipment, stating that the equipment operator 
is in the best position to detect incipient fires on the machine and is 
able to actuate a manual fire suppression system more easily than an 
automatic system. Some commenters stated that automatic fire 
suppression systems are not necessary on mobile diesel-powered 
equipment because this type of equipment will already be required to 
have fire protection and shutdown features. Commenters also stated that 
automatic systems can require extra maintenance and are susceptible to 
vibration, which can cause them to discharge unexpectedly. In addition, 
commenters stated that automatic fire suppression systems should not be 
required on vehicles with surface temperature controls, such as 
permissible vehicles, because compatible permissible systems were not 
available at the time of the proposal.
    Other commenters supported the proposal for automatic fire 
suppression systems on all types of diesel-powered equipment. In 
testimony before the Diesel Advisory Committee, equipment manufacturers 
and mine operators endorsed the use of automatic fire suppression 
systems on several types of diesel-powered equipment and gave examples 
of current applications. Other commenters to the proposal observed that 
it might be difficult for an equipment operator to actuate a manual 
system depending on the type and size of a fire. These commenters 
expressed concern that an equipment operator could be overcome by the 
effects of a fire or explosion and not be able to manually extinguish 
the fire. Some commenters also expressed concern that a manually-
actuated system would be ineffective for a fire that started after the 
equipment had been shut off and the equipment operator had left the 
area.
    Paragraph (a) of this section of the final rule does not adopt the 
proposed requirement for installation of an automatic fire suppression 
system on all mobile diesel-powered equipment. Instead, the final rule 
establishes requirements for both manual and automatic fire suppression 
systems. The type of fire suppression system required for installation 
on diesel-powered equipment is specified in Sec. 75.1907(b)(2) for 
permissible equipment, and Sec. 75.1909 (h), (i), and (j)(3) for 
nonpermissible equipment.
    The Ontario fire accident data indicated that heavy-duty diesel-
powered equipment of the type defined in the final rule at 
Sec. 75.1908(a) presents a much greater fire hazard than light-duty 
equipment defined under the final rule at Sec. 75.1908(b). The data 
showed that heavy-duty diesel-powered equipment, which includes 
equipment that cuts or moves rock or coal, equipment that performs 
drilling or bolting functions, and fuel transportation units, had 247 
fires (85 percent) of the total number of fires. Heavy-duty equipment 
frequently works under load and can develop large areas of hot engine 
surfaces. This equipment is prone to mechanical breakdown, especially 
hydraulic hose and electrical cable failure, creating a serious risk 
that the equipment will develop both an ignition source and provide a 
source of fuel for a fire.
    By contrast, light-duty diesel-powered equipment, which under the 
final rule includes supply vehicles, maintenance vehicles, personnel 
carriers, and other equipment not used to move rock or coal, accounted 
for 43 (15 percent) of the total number of fires. Light-duty equipment 
is not used in the actual mining process and is generally not worked 
very hard and typically used only intermittently during a shift. While 
over a third of the fires on heavy-duty equipment were started by hot 
engine surfaces, fewer than 10 percent of the fires on light-duty 
equipment were started by hot engine surfaces. Fires related to the 
electrical system accounted for 60 percent of the light-duty equipment 
fires. Electrical fires tend to smolder and provide more time for 
action to be taken to extinguish the fires than do diesel fires.
    Although light-duty equipment still poses a fire risk, this risk 
can be adequately addressed by fire suppression systems which take into 
account the manner in which light-duty equipment is used and the types 
of fires that typically occur on it. The final rule, therefore, does 
not adopt the proposal that automatic fire suppression systems be 
installed on all diesel machines.
    A manually-actuated fire suppression system provides adequate 
protection on light-duty self-propelled equipment. This type of 
equipment is attended by its operator at all times that it is operating 
as required by Sec. 75.1916(d) of the final rule. As discussed by 
several commenters to the proposal, it has been their experience that a 
well-maintained manually-actuated fire suppression system is 
appropriate if the equipment is attended. These commenters stated that 
manually-actuated fire suppression systems are adequate in conjunction 
with additional protective features for fuel, hydraulic, and electrical 
systems, to provide fire protection on outby diesel-powered equipment. 
In addition to a manual fire suppression system, protective features 
for fuel, hydraulic, and electrical systems are required on both heavy-
duty and light-duty nonpermissible equipment under Secs. 75.1909 and 
75.1910 of the final rule.
    Automatic fire suppression systems are necessary on equipment that 
poses a higher fire risk. This includes heavy-duty equipment, which 
presents an increased fire hazard as discussed above. It also includes 
equipment for which the operator is not immediately present at the 
controls of the machine at all times it is operated, such as 
compressors. Good fire fighting practice requires that the fire be 
attacked as early as possible. Further, several reports indicate that 
the rapid growth of fire prevented the equipment operator from 
actuating the manual fire suppression system. Automatic systems provide 
a fast response without operator intervention. Compressors and other 
non-self-propelled equipment frequently operate for long periods of 
time under high load. This results in sustained high engine surface 
temperatures, which can provide an ignition source for a fire and 
increase the likelihood of a a mechanical failure providing a fuel 
source for a fire. Also, the individual operating the compressor may be 
some distance from the machine, and would not be able to promptly 
actuate the fire suppression system. To address these hazards, the 
final rule adopts the proposed requirement for automatic fire 
suppression systems for heavy-duty and non-self-propelled equipment.
    One commenter to the proposal stated that the requirement in 
paragraph (a) that the ``system be suitable for the intended 
application'' was ambiguous and could be subject to different 
interpretations. This commenter stated that the term ``suitable'' could 
refer to a system that is suitable for a particular type of fire (class 
B flammable or combustible liquid fire) or it could mean that the 
system has a sufficient capacity to extinguish a fire on a particular 
piece of equipment. Other commenters recommended that the final rule 
specify the capacity of the fire suppression system.
    The final rule responds to commenters' concerns by requiring that

[[Page 55475]]

fire suppression systems be multipurpose dry chemical type (ABC) fire 
suppression systems listed or approved by a nationally recognized 
independent testing laboratory, and appropriate for installation on 
diesel-powered equipment. The final rule does not adopt the language 
``suitable for the intended application.''
    The capacity and suitability of fire suppression systems for 
protecting against specific fire hazards are specified as part of the 
listing or approval by the nationally recognized independent testing 
laboratory. The nationally recognized independent testing laboratory 
system listing or approval does not necessarily designate the system 
for a specific type of equipment, such as fuel transportation units or 
even diesel-powered equipment. Instead, the listing or approval uses a 
more general description such as mobile mining equipment or vehicle 
protection. Listing or approval by a nationally recognized independent 
testing laboratory ensures that a fire suppression system is properly 
designed for a particular type of fire protection hazard by putting the 
system through a series of specific performance tests. The system must 
also meet rigid design requirements in order to gain approval or 
listing.
    Fire suppression systems should be installed by a qualified 
individual following the installation and maintenance instructions in 
the system manufacturer's installation manual. The sizing of a fire 
suppression system is dependent on the number of nozzles needed to 
adequately cover all of the fire hazard areas that have been 
identified. The number of dry chemical canisters required will be 
proportional to the number of hazard areas that must be covered by the 
nozzles. This information can be obtained from the installation manual 
that is part of the listing or approval documentation. Other 
installation considerations, such as proper location and guarding of 
nozzles and other system components to prevent damage, are addressed in 
the system's installation manual. In addition to the installation 
requirements in the manual, follow-up maintenance and inspection 
procedures are provided.
    Also modified in this section from the proposal is the term 
``chemical'' replacing the term ``powder'' and the addition of the 
letter references ``ABC'' for the three classes of fire. These 
modifications are made in response to commenters' requests for 
clarification and to incorporate more appropriate terminology.
    A multipurpose dry chemical type system is capable of suppressing 
the three classes (ABC) of fires on diesel-powered equipment. A class A 
fire refers to fires of combustible solid materials such as paper, 
rubber, textiles, and cloth, and would typically involve such items as 
tires, hosing or seats on diesel-powered equipment. A class B fire on 
diesel-powered equipment would involve diesel fuel. Class C fires 
involve electrical components, and could include such components as 
lights, pumps, and components of the control panel on diesel-powered 
equipment. A multipurpose dry chemical type agent is specifically 
designed to extinguish ABC class fires.
    Paragraph (a)(1) of the final rule, like the proposal, requires 
that the fire suppression system be installed in accordance with the 
manufacturer's specifications and the limitations of the nationally 
recognized independent testing laboratory listing or approval. 
Commenters generally expressed support for this aspect of the proposal. 
This requirement ensures that the system is installed within the limits 
defined by the listing or approval organization and as specified by the 
fire suppression system manufacturer. Since the system already is 
performance-tested to a specific standard and in certain 
configurations, it must be installed within these parameters to be 
effective.
    Paragraph (a)(2) adopts the requirement from the proposal that the 
fire suppression system be installed in a protected location or guarded 
to minimize physical damage from routine vehicle operations. No 
specific comments were received on this aspect of the proposal. In 
order for fire suppression systems to work properly, they must not be 
subjected to damage from the mining environment. Damage to any part of 
the fire suppression system can result in a malfunction of the entire 
system and in the system not responding to a fire. For example, a rock 
fall can pinch a hose or crush a sensor and create faults that can 
disable either the entire system or a portion of the system that covers 
a certain area of the machine.
    Paragraph (a)(3), like the proposal, requires that the suppressant 
agent distribution tubing or piping be secured and protected against 
damage, including pinching, crimping, stretching, abrasion, and 
corrosion, and that the discharge nozzles be positioned and aimed for 
maximum fire suppression effectiveness in the protected areas. No 
specific comments were received on this aspect of the proposal. During 
the normal operation of diesel-powered equipment in the confined space 
of a coal mine, a fire suppression system can become damaged from 
collision or nozzles positioned at a specific predetermined location 
can be redirected away from a fire hazard.
    Paragraph (a)(4), like the proposal, requires that fire suppression 
nozzles also be protected against the entrance of foreign materials. No 
specific comments were received on this aspect of the proposal. The 
openings in the nozzles used on multipurpose dry chemical fire 
suppression systems can be as small as \1/8\ of an inch. If material 
such as mud, coal dust, or rock dust enters the nozzle, it can prevent 
the chemical agent from discharging entirely, or alter the pattern and 
coverage of fire suppressant.
    Paragraph (b) of the final rule requires fire suppression and, if 
the system is automatic, fire detection for certain coverage areas on 
diesel-powered equipment. Under the final rule, the coverage areas 
include the engine (including the starter), transmission, hydraulic 
pumps and tanks, fuel tanks, exposed brake units, air compressors and 
battery areas on diesel-powered equipment and electric panels or 
controls used on fuel transportation units. This requirement ensures 
that fire detection and fire suppression are provided with coverage for 
key areas of diesel-powered equipment and fuel transportation units.
    Although the listing or approval generally describes areas on 
equipment that pose a fire hazard, it does not specifically identify 
which hazards must be covered by fire suppression. The final rule's 
requirement for specific fire suppression coverage for certain areas on 
diesel-powered equipment is supported by the Ontario fire data. The 
data showed that engine fires accounted for 99 (34 percent) of the 
total number of fires on diesel-powered equipment. Included in engine 
fires were 10 compressor fires, 27 hydraulic system fires, 11 
transmission fires, and 7 fuel tank fires. The Ontario fire data also 
indicate 32 battery fires and 55 brake fires.
    The scope of paragraph (b) is expanded to include the starting 
mechanism on diesel-powered equipment. This responds to commenters' 
recommendations that foreign fire data be evaluated to establish 
criteria for fire protection on diesel-powered equipment. The Ontario 
fire accident data indicate that starters, starter solenoids, and the 
wiring associated with these components present a fire hazard. The data 
showed 21 (17 percent) of the electrical fires on self-propelled 
diesel-powered equipment were caused by starter circuits. Also, the 
proposal included the engine compartment as an area to be

[[Page 55476]]

covered by the fire suppression system. The specific reference to the 
starter area in the final rule clarifies that the starter area of the 
engine compartment be covered by the fire suppression system.
    The proposed rule specified fire suppression system coverage areas 
for various types of limited class equipment. Because of the different 
fire hazards presented by the various types of equipment listed in the 
proposal, separate provisions in proposed paragraph (b)(1) were 
included. In the final rule the limited class category of light-duty 
equipment is expanded to include a range of equipment types, beyond the 
types defined in the proposal, and the requirements for coverage areas 
have been combined.
    Proposed paragraph (b)(2) has not been adopted in the final rule to 
the extent that it would have specified coverage areas around fuel 
transportation units in response to commenters' statements that fuel 
tanks by themselves do not constitute a fire hazard, and only need 
coverage if an associated ignition source is present. Proposed 
paragraph (b)(3), which would have required fire suppression coverage 
for fuel containers and electric panels or controls used during fuel 
transfer operations on fuel transportation units, has not been adopted 
because the term ``container'' is no longer used in the final rule. The 
phrase ``during fuel transfer operations'' was not adopted from the 
proposal to eliminate the inference that only electric panels or 
controls used during fuel transfer operations must have coverage. Under 
the final rule, electrical components installed on fuel transportation 
units must be covered by fire suppression systems. However, a vehicle's 
instrument panel located in the operator's compartment of the machine 
would not be considered ``electrical panels and controls.'' Expelling 
fire suppressant in the operator's compartment would create other 
hazards for the equipment operator such as a cloud of fire suppressant 
which could limit visibility.
    Paragraph (c), like the proposal, requires that automatic fire 
suppression systems include audible and visual alarms to warn of fires 
or system faults. No specific comments were received on this aspect of 
the proposed rule. This requirement provides a means for immediate 
notification of the equipment operator, both audibly and visually, when 
the system detects a fire on the machine or a problem with the fire 
detection device. The audible and visual indication of fire detection 
can alert the equipment operator of the imminent discharge of the 
chemical agent and the engine shutdown required by paragraph (d).
    Paragraph (d) of the final rule adopts the proposed requirement 
that the fire suppression system provide for automatic engine shutdown. 
The final rule also provides that if the fire suppression system is 
automatic, engine shutdown and discharge of suppressant agent may be 
delayed for a maximum of 15 seconds after the fire is detected by the 
system. Commenters expressed support for this aspect of the proposed 
rule.
    The engine shutdown requirement is intended to prevent an engine 
from continuing to run once the system has been actuated, either 
automatically or manually. This will prevent the engine from pumping 
diesel fuel or hydraulic fluid through a leaking fuel line or hydraulic 
hose, fueling the fire that the fire suppression system is attempting 
to extinguish. Since fire suppression systems are designed to suppress 
fires in their incipient stages, the contribution of additional fuel to 
the fire may render the system ineffective. The Ontario accident data 
included a number of machine fires where the engine continued to feed 
the fire with diesel fuel or hydraulic fluid, reducing the 
effectiveness of the system's ability to suppress the fire. In 
addition, the engine shutdown feature prevents the engine cooling fan 
from dispersing the fire suppressant agent before it extinguishes the 
fire. A maximum of 15 seconds delay between the time of fire detection 
and actuation provides a limited period of time for the equipment 
operator to stop and exit the machine before the machine engine shuts 
down.
    Paragraph (e) of the final rule adopts the proposed requirement 
that the fire suppression system be operated by at least two manual 
actuators. One actuator must be located on each side of the equipment, 
and if the equipment is provided with an operator's compartment, one 
actuator must be located in the compartment within easy reach of the 
equipment operator.
    Several commenters expressed the opinion that two manual actuators 
were unnecessary on small units of diesel equipment, such as tractors, 
when the second actuator would have to be installed in close proximity 
to the engine. Another commenter urged that actuators be separated from 
each other by a means of a check valve or other device to allow the 
system to operate even if there is an open line in the actuation 
circuit.
    Two actuators for a fire suppression system are important to afford 
ample opportunity to initiate the system, even on small units of 
diesel-powered equipment. For example, if only one actuator were 
located on the side of a piece of equipment, the equipment operator 
might be unable to access the actuator due to the confined spaces in an 
underground coal mine, or because the fire ignited in the same location 
as the actuator. The final rule requirement for two manual actuators is 
also consistent with existing Sec. 75.1107 for dry chemical fire 
suppression systems for electric equipment.
    The final rule does not include a requirement for a check valve 
between the actuators for fire suppression systems. This is part of the 
system design and is more appropriately addressed by the system 
manufacturer and the listing or approving nationally recognized 
independent testing laboratory.
    Paragraph (f) adopts the proposed requirement that the fire 
suppression system must remain operative in the event of engine 
shutdown, equipment electrical system failure, or failure of any other 
equipment system. No specific comments were received on this aspect of 
the proposed rule. This requirement is intended to ensure that the 
functioning of the system is not dependent on any external power 
source, such as an engine-driven alternator, vehicle battery, or the 
proper operation of any other machine system.
    Paragraph (g), like the proposal, requires that the electrical 
components of each fire suppression system installed on diesel-powered 
equipment used where permissible electric equipment is required be 
permissible or intrinsically safe, and that such components be 
maintained in permissible or intrinsically safe condition. This 
provision requires that automatic fire suppression systems be certified 
or approved by MSHA under part 18.
    A number of commenters to the proposal stated that intrinsically 
safe vehicle-type automatic fire suppression systems were not 
available. Currently, however, two fire suppression system 
manufacturers have obtained approval under part 18 for their automatic 
fire suppression systems.
    Paragraph (h) adopts the requirement from the proposal that 
electrically operated detection and actuation circuits be monitored and 
provided with status indicators showing power and circuit continuity. 
If the system is not electrically operated, a means must be provided to 
indicate the functional readiness status of the detection system. These 
features notify the equipment operator or maintenance person of the 
functional readiness status of both the detection and actuation circuit 
and the power source. No specific comments

[[Page 55477]]

were received on this aspect of the proposed rule.
    Currently at least one manufacturer is marketing an automatic fire 
suppression system with these electrical features on both permissible 
and nonpermissible systems. There is also an automatic system which is 
not electrically operated and employs a pressurized cylinder to 
disperse the suppressant. A pressure gauge on the cylinder is 
considered sufficient to indicate the condition of the system.
    Paragraph (i) requires that each fire suppression system be tested 
and maintained in accordance with the manufacturer's recommended 
inspection and maintenance program and as required by the nationally 
recognized independent testing laboratory listing or approval. It also 
requires fire suppression systems to be visually inspected at least 
once each week by a person trained to make such inspections.
    The proposed rule would have required each fire suppression device 
to be visually inspected at the same interval by a person qualified to 
make such inspections. The proposal also would have required that each 
fire suppression device be tested and maintained in accordance with 
applicable requirements in Sec. 75.1100.
    Commenters to the proposal generally expressed support for required 
maintenance of fire suppression systems installed on diesel-powered 
equipment. Some commenters, however, recommended that a maintenance 
program specifically designed for fire suppression systems be developed 
at each mine. One commenter stated that a visual inspection of fire 
suppression systems on diesel-powered equipment would not be adequate 
and recommended that fire suppression systems be maintained in 
accordance with the manufacturer's guidelines by either outside 
entities qualified by the equipment manufacturer or through a program 
to qualify individuals at the mine. Another commenter to the proposal 
recommended that the manufacturer's inspection and maintenance program 
be referenced in lieu of the requirements in Sec. 75.1100. One 
commenter stated that automatic fire suppression systems are more 
difficult to maintain than manual systems, but that both types of 
systems should be inspected monthly and maintained semi-annually as a 
minimum. Another commenter expressed concern that certain critical 
internal components of a fire suppression system could be checked 
simply by a visual inspection.
    Under the final rule, the weekly visual inspection is not intended 
to be an in-depth inspection. The weekly visual inspection is intended 
to be a quick check to determine if defects, such as disconnected hose 
lines or altered nozzles, are readily apparent. The in-depth inspection 
takes place as part of the manufacturer's recommended testing and 
inspection procedure also required under the final rule. Fire 
suppression system manufacturers are most familiar with the design and 
operation of their systems and are best able to identify the components 
that need maintenance as well as the type and frequency of maintenance. 
Adequate maintenance is essential because of the importance of these 
systems in suppressing machine fires. Maintenance and testing 
requirements for fire suppression systems are included in the final 
rule in addition to the requirement for a weekly visual inspection.
    The manufacturer's inspection and maintenance procedures are 
typically spelled out in great detail in the manufacturer's manual and, 
depending on the operating environment, include the recommended 
inspection intervals. In addition, these inspection and maintenance 
procedures are evaluated as part of the system's approval or listing by 
a nationally recognized independent testing laboratory.
    The requirement in this paragraph is identical to the requirement 
in existing Sec. 75.1107-16(a). However, the fire suppression system 
requirements in Secs. 75.1107-3 through 75.1107-16 cannot be directly 
applied to diesel-powered equipment for several reasons. Any 
modification of these existing requirements by inserting the term 
``diesel-powered'' in the regulatory language would result in an 
extremely confusing regulation. Also, the fire hazards presented by 
diesel-powered equipment are different from those on electric-powered 
equipment, due to the close proximity of large quantities of hydraulic 
oils and fuels to the heated diesel engine exhaust. The single 
modification made to this paragraph was replacing the term ``device'' 
with the term ``system''. This was done because MSHA intends that the 
whole system be inspected and not just individual components of the 
system.
    Although automatic systems have additional components that must be 
inspected and maintained, properly trained maintenance personnel should 
have little difficulty satisfying these requirements. It is anticipated 
that the training of the personnel assigned to perform the testing and 
maintenance of fire suppression systems will be provided by the system 
manufacturer or distributor. Additionally, automatic fire suppression 
systems under the final rule are required to have a status monitoring 
feature to tell the equipment operator or maintenance personnel that a 
problem exists.
    Section 75.1915(b)(3)(iv) of the final rule requires that the 
training and qualification program for qualified persons working on 
diesel equipment address tests and maintenance of fire suppression 
systems. The qualified person conducting maintenance on fire 
suppression systems on diesel-powered equipment should have sufficient 
familiarity with the elements of the fire suppression system. A person 
``trained'' to perform inspections and tests required by paragraph (i) 
of this section of the final rule is not required to be a person 
qualified under Sec. 75.1915. However, the final rule intends that the 
person performing tests and inspections of fire suppression systems 
have sufficient knowledge to determine whether a fire suppression 
system is functioning properly. MSHA anticipates that since fire 
suppression systems are common to both electric and diesel equipment, 
the mine operator will work with either the fire suppression system 
manufacturer or distributor to ensure that personnel responsible for 
the maintenance of fire suppression systems are adequately trained.
    Paragraphs (j) of the final rule establishes recordkeeping 
requirements which address the inspection and maintenance requirements 
for fire suppression systems set forth in paragraph (i). Paragraph (j) 
of the final rule requires that persons performing inspections and 
tests of fire suppression systems record results of tests and 
inspections only when a fire suppression system does not meet the 
installation or maintenance requirements of this section. Under these 
circumstances, the person performing the inspection or test is required 
to record the equipment on which the fire suppression system did not 
meet the installation or maintenance requirements of this section, the 
defect found, and the corrective action taken. The final rule also 
requires that these records be kept either manually or electronically 
in a secured manner that is not susceptible to alteration. Paragraph 
(j)(3) requires that records be maintained at a surface location at the 
mine for one year and made available for inspection by an authorized 
representative of the Secretary and miners' representatives.
    The proposal would have required that a record be kept of all 
inspections and tests of fire suppression systems

[[Page 55478]]

and maintained at an appropriate location for each fire suppression 
device. One commenter to the proposal recommended that, in order to 
provide adequate maintenance of fire suppression systems, interested 
parties be allowed to view the results of visual inspections recorded 
in approved books. Another commenter recommended that records of 
inspections be maintained on the surface by the operator so that they 
would be available for MSHA verification. This commenter stated that 
maintaining separate records for inspections of fire suppression 
systems is an unnecessary burden for the mine operator. This commenter 
stated that records kept on computers, as pre-shift examinations and by 
normal maintenance inspections, would be adequate for documenting the 
inspections conducted on fire suppression systems.
    Office of Management and Budget guidance comments directed MSHA to 
reexamine the recordkeeping requirements in the proposal and 
recommended that the final rule require paperwork that was the least 
burdensome necessary. MSHA has done so, and the final rule does not 
adopt the proposal that all fire suppression system test and 
maintenance results be recorded. In response to commenters and 
consistent with other provisions of the final rule, paragraph (j) 
requires that records of inspections and tests be made only when a fire 
suppression system does not meet the installation or maintenance 
requirements of this section. This requirement is important because if 
a fire suppression system does not meet the installation or maintenance 
requirements of this section, the defect could be sufficiently serious 
to cause the system to fail in the event of a fire. This requirement is 
intended to ensure that records are maintained and made available to 
interested parties when a defect is found, and that the appropriate 
level of mine management is made aware of defects requiring corrective 
action.
    The final rule does not specify a particular way of recording the 
test and maintenance data, only that the records be located at the 
surface of the mine. The records of the inspections and tests must be 
made in a secure media not susceptible to alteration. A detailed 
discussion of the subject of acceptable record books and electronic 
records can be found under the heading ``Recordkeeping Requirements'' 
in the General Discussion section of this preamble.
    The final rule does not adopt the requirement from the proposed 
rule that records of inspections be maintained at an appropriate 
location near each fire suppression system. Instead, paragraph (k) of 
the final rule establishes the requirement recommended by a commenter 
that records of inspections and tests be maintained at a surface 
location at the mine. Storing records on the surface at the mine makes 
them more accessible to interested parties. Also in response to 
commenters, the final rule provides access to not only miners' 
representatives but to authorized representatives of the Secretary. 
This provision ensures that test and inspections of fire suppression 
systems are being made and, when a defect is found, that corrective 
action is taken.
    Records for inspection of diesel-powered equipment are also 
required under Sec. 75.1914(f)(2) of the final rule. However, the 
recordkeeping requirement under paragraph (j) is not intended to be 
duplicated. While Sec. 75.1914(f)(2) applies to diesel-powered 
equipment, some diesel fuel transportation units may be portable 
trailers with only electrical components and therefore would need to be 
covered under the recordkeeping requirement under paragraph (j) of this 
section. The only records required for fire suppression systems under 
this section of the final rule are for tests and maintenance required 
under paragraph (i).
    Paragraph (k) adopts the proposed requirement that all miners 
normally assigned in the active workings of the mine be instructed 
about the hazards inherent to the operation of fire suppression 
systems, and where appropriate, the safeguards available for each 
system. This requirement is intended to ensure that all miners working 
in areas where fire suppression systems operate are instructed in any 
inherent hazards and necessary precautions associated with the 
operation of these systems. The final rule modifies the proposal in 
that the term ``device'' has been replaced by the term ``system'' to 
clarify that this requirement applies to the entire fire suppression 
system, not merely a component of it.
    One commenter to the proposal agreed with the requirement that 
miners be trained in the hazards and safeguards of fire suppression 
systems, but recommended that such training be incorporated in the 
annual refresher training required under existing Sec. 75.1101-23 for 
the program of instruction, location and use of fire fighting 
equipment. Under the final rule, it is anticipated that the instruction 
on the hazards of fire suppression systems required by this paragraph 
will be part of the Sec. 75.1101-23 instruction.
    Paragraph (l) of this section of the final rule provides that, for 
purposes of existing Sec. 75.380(f), a fire suppression system 
installed on diesel-powered equipment and meeting the requirements of 
Sec. 75.1911 is equivalent to a fire suppression system meeting the 
requirements of Secs. 75.1107-3 through 75.1107-16.
    Section 75.380 addresses requirements for escapeways in bituminous 
and lignite mines. Section 75.380(f) specifies the equipment that can 
be used in the primary escapeway and the type of fire suppression 
system required to be installed on this equipment. Section 75.380(f)(4) 
requires that each piece of mobile equipment operated in primary 
escapeways, except for continuous miners and as provided in paragraphs 
(f)(5), (f)(6) and (f)(7) of the section, be equipped with a fire 
suppression system installed according to Secs. 75.1107-3 through 
75.1107-16 that is: (1) manually operated and attended continuously by 
a person trained in the system's function and use; or (2) a 
multipurpose dry chemical type capable of both automatic and manual 
activation. The requirement in Sec. 75.380(f)(4) for installation of a 
fire suppression system that meets the requirements of Secs. 75.1107-3 
through 75.1107-16 on equipment operating in the primary escapeway 
presents a potential conflict with the requirement for installation of 
a fire suppression system on diesel-powered equipment in Sec. 75.1911.
    As noted earlier, several commenters to the proposed rule believed 
that the requirements for fire suppression systems in Secs. 75.1107-3 
through 75.1107-16 should be made applicable to diesel-powered 
equipment. However, the requirements in Secs. 75.1107-3 through 
75.1107-16 make specific reference to electric equipment and components 
and are not practical for diesel-powered equipment. Any modification of 
these existing requirements by inserting the term ``diesel-powered'' in 
the regulatory language would result in an extremely confusing 
regulation.
    After a review of the issue, MSHA has determined that fire 
suppression systems installed on diesel-powered equipment meeting the 
requirements of Sec. 75.1911 afford at least equivalent protection to 
fire suppression systems meeting the requirements of Secs. 75.1107-3 
through 75.1107-16. Many of the requirements contained in 
Secs. 75.1107-3 through 75.1107-16 are similar to those in 
Sec. 75.1911. Both sections include requirements for: listed or 
approved fire

[[Page 55479]]

suppression systems; the capacity and size of fire suppression system 
hardware; a system design that will withstand the normal rigors of 
mining; compatibility of the extinguishing agent with the mine 
atmosphere; the system's ability to operate independently of an 
equipment power supply; sensor operability status indication; and the 
inclusion of manual actuators. Consequently, the final rule makes clear 
that fire suppression systems meeting the requirements of Sec. 75.1911 
will satisfy the requirements of Sec. 75.380(f)(4).
Section 75.1912  Fire Suppression Systems for Permanent Underground 
Diesel Fuel Storage Facilities
    This section of the final rule establishes requirements for the 
design, installation and maintenance of fire suppression systems at 
permanent underground diesel fuel storage facilities. Under the final 
rule, a permanent underground diesel fuel storage facility is defined 
as a facility designed and constructed to remain at one location for 
the storage or dispensing of diesel fuel, which does not move as mining 
progresses. Section 75.1903(a)(5) of the final rule requires that 
permanent underground diesel fuel storage facilities be equipped with 
an automatic fire suppression system that meets the requirements of 
Sec. 75.1912.
    The Diesel Advisory Committee recommended that automatic fire 
suppression systems be used to address potential fire hazards from 
ignition and fuel sources at permanent underground diesel fuel storage 
facilities. The proposed rule included design, installation and 
maintenance requirements for automatic fire suppression systems for 
diesel fuel storage areas and stationary diesel-powered equipment.
    Commenters to the proposed rule generally accepted the need for 
fire suppression systems at permanent underground diesel fuel storage 
facilities. However, comments varied on what the requirements for fire 
suppression systems should be. Some commenters recommended that only 
manufacturer's requirements for design, installation and maintenance be 
used. Other commenters recommended a more detailed approach and 
suggested that the final rule outline specific requirements for fire 
suppression systems.
    The storage of diesel fuel at permanent underground facilities 
presents a limited fire hazard when fuel is contained in diesel fuel 
tanks and safety cans constructed of noncombustible material. However, 
diesel fuel does present a fire hazard when it is spilled from a tank 
or leaked from a hose and comes into contact with an ignition source. 
Spills and leaks of diesel fuel at permanent underground storage 
facilities can occur when machinery is being refueled, when diesel fuel 
is being placed in or taken out of storage tanks, or when tanks are 
damaged or not properly maintained. Potential ignition sources at 
permanent underground storage facilities include a running diesel 
vehicle with hot surfaces or hot brake components, malfunctioning 
electric valves, or pumps used to dispense diesel fuel.
    Fire suppression systems are designed to extinguish fires quickly, 
in their incipient stage, and to reach all locations where a fire may 
occur. This is important at permanent underground diesel fuel storage 
facilities because a fire must be extinguished quickly before fuel can 
further propagate a fire. For example, if a fire is not extinguished at 
an early stage, leaking diesel fuel can fuel a fire and result in an 
increase of the intensity and size of the fire.
    Fixed fire suppression systems also offer two advantages over 
portable fire extinguishers: fast attack and application of the 
suppressant to difficult-to-reach areas where fires may occur. In 
addition, an automatic fire suppression system has the advantage of 
detecting and suppressing fires without a person in attendance. Because 
permanent underground diesel fuel storage facilities will not always be 
attended, it is necessary to require a means of electrically or 
mechanically detecting a fire as well as electrically or mechanically 
activating the fire suppression system upon fire detection. This is 
important since the potential hazard for mine personnel throughout the 
mine is significant if a fire in a diesel fuel storage facility could 
burn unnoticed.
    The proposed rule would have established requirements for fire 
suppression devices for permanent underground diesel fuel storage areas 
and stationary unattended diesel-powered equipment. Because 
Sec. 75.1916(d) of the final rule requires all diesel-powered equipment 
to be attended while operating, and because proposed requirements for 
stationary unattended equipment have not been adopted in the final 
rule, Sec. 75.1912 of the final rule has been modified to apply only to 
permanent underground diesel fuel storage facilities.
    A number of commenters to the proposal expressed concern with the 
requirements for fire suppression systems at permanent underground 
diesel fuel storage facilities. One commenter stated that since diesel 
fuel is a Class II combustible liquid, a diesel fuel storage station 
used and moved with a working section should be treated similar to a 
lubricating oil or grease storage station. This commenter expressed the 
view that requirements for limiting the quantity of diesel fuel in 
temporary storage and requiring portable fire extinguisher protection 
would be adequate safeguards. Another commenter expressed concern with 
the ability of a dry compound to suppress a fire over a long enough 
period of time to prevent re-ignition. This commenter stated that high 
volumes of ventilating air in a mine can blow dry compound away from 
the area it is attempting to protect before it can cool down a hot 
surface created by a fire.
    MSHA agrees with the commenter who stated that diesel fuel stored 
on and moved with a section should be treated as a Class II combustible 
liquid. The final rule addresses this comment by establishing the 
allowance for one temporary underground diesel fuel storage area for 
the short-term storage and dispensing of diesel fuel on each working 
section, which can move as mining progresses. A temporary underground 
diesel fuel storage area is defined under Sec. 75.1900 of the final 
rule as an area of the mine provided for the short-term storage of 
diesel fuel in a fuel transportation unit, which moves as mining 
progresses. These temporary underground diesel fuel storage areas are 
required to meet the requirements in Secs. 75.1902, 75.1903 and 75.1906 
of the final rule. All other diesel fuel storage areas will be treated 
as permanent storage facilities and must comply with all of the 
requirements for such facilities. Permanent diesel fuel storage 
facilities pose a higher risk of fire than oil and grease storage areas 
because diesel fuel is generally stored in much greater quantities in 
underground coal mines. In addition, diesel fuel has a lower flash 
point than either lubricating oil or grease and can be more easily 
ignited by a hot surface.
    Although permanent diesel fuel storage facilities are provided with 
ventilating air during normal operations, these facilities are required 
under Sec. 75.1903(a)(2) of the final rule to be equipped with either a 
self-closing door or a means for automatic enclosure upon actuation of 
the fire suppression system. This feature should prevent any 
ventilating air from affecting the suppressant agent.
    An automatic fire suppression system uses a supplemental detection 
device to provide an early warning of a fire. The fire detection 
system, which is generally activated by either smoke or heat,

[[Page 55480]]

automatically sends a signal to the system for the discharge of 
suppressant agent. Automatic fire suppression systems activate a 
network of piping and nozzles to allow suppressant agent to be released 
and distributed directly at a predetermined fire hazard.
    Under the final rule, automatic fire detection and fire suppression 
systems are required to provide fire suppression for all areas of a 
permanent underground diesel fuel storage facility. The final rule also 
requires that the system include audible and visual alarms to warn of 
fires or system faults and automatic electrical system shutdown in the 
event of a fire. In addition, the final rule requires all fire 
suppression systems to be tested and maintained in accordance with 
manufacturer's recommendations. Finally, the final rule establishes 
certain recordkeeping requirements for fire suppression systems that 
are found not to meet required specifications during inspection and 
testing.
    Paragraph (a) of this section of the final rule requires that a 
fire suppression system required by Sec. 75.1903(a)(5) be an automatic 
multipurpose dry chemical type (ABC) fire suppression system listed or 
approved as an engineered dry chemical extinguishing system by a 
nationally recognized independent testing laboratory and appropriate 
for installation at a permanent underground diesel fuel storage 
facility.
    The proposed rule would have required an automatic multipurpose dry 
powder type fire suppression system suitable for the intended 
application and listed or approved by a nationally recognized 
independent testing laboratory.
    A commenter to the proposal stated that this paragraph should 
require that ``an automatic fire suppression system suitable for the 
intended application shall be installed to protect the entire area 
inside the fire proof enclosure.'' This commenter believed that all of 
the necessary requirements for fire suppression systems were already 
addressed in existing part 75, and that it was unnecessary to identify 
protected coverage components inside the storage facility if the entire 
area is required to be protected. Another commenter stated that the 
requirement in the proposal that the ``system be suitable for the 
intended application'' was ambiguous and could be subject to different 
interpretations. This commenter stated that the term ``suitable'' could 
refer to a system that is suitable for a particular type of fire (class 
B or combustible liquid fire) or it could mean that the system has a 
sufficient capacity to extinguish a fire. This commenter also 
recommended that the final rule specify the capacity of fire 
suppression systems installed at permanent underground diesel fuel 
storage facilities.
    In response to commenters, MSHA evaluated whether the requirements 
for fire suppression systems in existing Sec. 75.1107 should be 
extended to apply to permanent underground diesel fuel storage 
facilities, but has concluded that such an extension would not be 
appropriate. The fire hazards that exist at permanent underground 
diesel fuel storage facilities are different from those on electric-
powered equipment, due to the storage of large quantities of diesel 
fuel in close proximity to ignition sources at these facilities. 
Additionally, because existing Sec. 75.1107 makes specific reference to 
electrical controls and components on electric-powered equipment, a 
modification of the existing requirements by inserting the term 
``permanent underground diesel fuel storage facility'' in the 
regulatory language would result in an extremely confusing regulation. 
Existing fire suppression requirements in part 75 have therefore not 
been applied to permanent underground fuel storage facilities.
    In response to commenters' suggestions, the final rule does not 
adopt the phrase ``suitable for the intended application'' from the 
proposal. Instead, the final rule includes the more specific language 
``listed or approved as an engineered dry chemical extinguishing system 
approved by a nationally recognized independent testing laboratory.'' 
This modification is intended to clarify that an automatic fire 
suppression system installed at a permanent underground diesel fuel 
storage facility must be listed or approved by a nationally recognized 
independent testing laboratory specifically for a fixed engineered dry 
chemical extinguishing system unit.
    The capacity and suitability of fire suppression systems for 
protecting against specific fire hazards are specified as part of the 
listing or approval by the nationally recognized independent testing 
laboratory. The listing or approval ensures that a fire suppression 
system is properly designed for a particular type of fire protection 
hazard by putting the system through a series of specific performance 
tests. The system must also meet rigid design requirements in order to 
gain listing or approval.
    Fire suppression systems should be installed by a qualified 
individual following the installation and maintenance instructions in 
the system manufacturer's installation manual. The sizing of a fire 
suppression system is dependent upon the number of nozzles needed to 
adequately cover the entire area of a permanent underground diesel fuel 
storage facility. The number of dry chemical canisters required will be 
proportional to the amount of area that must be covered by the nozzles. 
This information can be obtained from the installation manual that is 
part of the listing or approval documentation. Other installation 
considerations, such as proper location and guarding of nozzles and 
other system components to prevent damage, are addressed in the 
system's installation manual. In addition to the installation 
requirements, the manual includes provisions for follow-up maintenance 
and inspection procedures.
    One commenter to the proposal recommended that the term ``dry 
powder'' be deleted from paragraph (a) because this commenter believed 
that there were many equally effective systems, such as foam/water 
spray systems, available to protect against fire hazards. Another 
commenter stated that the terms ``listed'' and ``approved'' were not 
strong enough. This commenter stated that there was no way of verifying 
whether a system had been ``listed'' or ``approved'' and recommended 
that the term ``tested'' replace the term ``listed''.
    Although dry chemical is the most commonly used type of suppressant 
agent in the mining environment and is specifically referenced in 
paragraph (a) of the final rule, paragraph (a)(1) of the final rule 
allows for alternate types of fire suppression systems that are no less 
effective. In addition, the requirement that a system be listed or 
approved by a nationally recognized independent testing laboratory is 
more stringent than using the term ``tested''. Under the final rule, 
when a system is listed or approved by a nationally recognized 
independent testing laboratory, it means that the system has met 
performance and design requirements outlined in an industry standard in 
a certain configuration and for a specific function. Also, if a system 
has been listed or approved by a nationally recognized independent 
testing laboratory, it means that the system has met other requirements 
for inspection, maintenance, and quality control assurances.
    Also modified in this paragraph from the proposal is the term 
``chemical'' replacing the term ``powder'' and the addition of the 
reference ``ABC'' for the three classes of fire. These modifications 
were made in response to commenters' request for clarification and to 
incorporate more appropriate terminology.

[[Page 55481]]

    A multipurpose dry chemical type agent is the most commonly used 
and successfully applied type of suppressant agent in fire suppression 
systems in underground coal mines. This type of agent is specifically 
designed to extinguish ABC class fires. A class A fire refers to a fire 
of combustible solid materials such as paper, rubber, textiles, and 
cloth, and would involve such items as hosing at a permanent 
underground diesel fuel storage facility. A class B fire would include 
diesel fuel. Class C fires involve electrical components and could 
include such components as lights, pumps, and valves at permanent 
underground diesel fuel storage facilities.
    The term ``engineered'' was added to the final rule in response to 
commenters' concerns regarding the adequacy of a fire suppression 
system to address all of the fire hazards at a permanent underground 
diesel fuel storage facility. An engineered fire suppression system 
will ensure that all of the fire hazards are addressed since a 
representative from a fire suppression system manufacturer will go to 
the facility and evaluate all of the fire hazards. The evaluation by 
the system manufacturer representative also includes determining the 
appropriate coverage areas for the fire suppression system, the number 
and size of dry chemical canisters, the length of piping, and the 
number of nozzles.
    The proposed rule would have allowed the use of inert or halogenate 
gas suppressant agents in unoccupied and enclosed areas where the use 
of such suppressants would not pose a toxic hazard. One commenter to 
the proposal recommended that the use of inert or halogenate gas 
suppressant agents be prohibited because they create a toxic hazard. 
This requirement has not been included in the final rule because inert 
or halogenated gas fire suppression systems are considered an alternate 
type of fire suppression system that are addressed in paragraph (a)(1) 
of this section of the final rule. The potential toxic hazard presented 
by inert or halogenated gas suppressant agent will be evaluated by MSHA 
on a case-by-case basis as an alternate type system. In addition, 
typical inert gas agents such as halon 1211 and 1301 are no longer 
being marketed due to their reported contribution to the ozone 
depletion of the environment.
    Paragraph (a)(1) of the final rule adopts the provision from the 
proposal that alternate types of fire suppression systems be approved 
in accordance with Sec. 75.1107-13 of this part. This paragraph of the 
final rule is intended to allow the use of fire suppression systems 
other than dry chemical systems, so long as they provide substantially 
equivalent protection. Under the final rule, MSHA will evaluate 
alternate types of fire suppression systems, such as foam/water 
sprinkler-based systems, using the criteria set forth in existing 
Sec. 75.1107-13.
    One commenter to the proposal objected to this provision and stated 
that only the manufacturer who designs and constructs these systems 
will know the exact capabilities and limitations of the system. This 
commenter also stated that this requirement would result in the 
installation of inadequate fire suppression systems at permanent 
underground diesel fuel storage facilities, because the requirements in 
existing Sec. 75.1107-13 are applicable to fire suppression systems 
installed on equipment.
    Existing Sec. 75.1107-13 establishes criteria for the approval of 
alternate fire suppression devices. Under Sec. 75.1107-13, the 
appropriate MSHA district manager may approve any fire suppression 
system or device which provides substantially equivalent protection to 
what would be achieved through compliance with the standard.
    The final rule does not intend to allow alternate types of fire 
suppression systems that do not adequately address fire hazards at 
permanent underground diesel fuel storage facilities. Instead, all 
types of alternate fire suppression systems must be installed and 
operated in strict accordance with the system manufacturer's 
recommendations as specified in paragraph (a)(2) of this section of the 
final rule. Any type of fire suppression system that is not designed 
and constructed in accordance with industry standards for fire 
protection will be unacceptable.
    Paragraph (a)(2) of the final rule adopts the requirement from the 
proposal that the suppression system be installed in accordance with 
the manufacturer's specifications and the limitations of the nationally 
recognized independent testing laboratory listing or approval. One 
commenter to the proposal expressed the view that the term ``listing'' 
was not specific enough and recommended that the language ``independent 
testing'' be added. As explained earlier, a listing or approval by a 
nationally recognized independent testing laboratory is more stringent 
than the use of the term ``testing''. This comment has therefore not 
been adopted in the final rule.
    This requirement ensures that the system is installed within the 
limits defined by the listing or approval issued by the nationally 
recognized independent testing laboratory and as specified by the fire 
suppression system manufacturer. Since the system is performance-tested 
to a specific standard and in certain configurations, it must be 
installed within these parameters to be effective.
    Paragraph (a)(3) adopts the requirement from the proposal that the 
fire suppression system be installed in a protected location or guarded 
to prevent physical damage from routine operations. Damage to any part 
of the fire suppression system can result in a malfunction of the 
entire system and in the system not responding to fire hazards. For 
example, a rock fall can pinch a hose or crush a sensor and create 
faults that can disable the entire system or a portion of the system.
    One commenter stated that the proposed rule did not define what 
protections were necessary on fire suppression systems and suggested 
that the systems be fully protected from physical elements, including 
rib and roof falls. This commenter further stated that this protection 
is already provided for electrical circuit breakers under existing 
Sec. 75.901, and that this type of protection is even more vital for 
the protection of fire suppression systems.
    This comment has not been adopted in the final rule because the 
construction requirements for permanent underground diesel fuel storage 
facilities at Secs. 75.1902 and 75.1903 ensure that fire suppression 
systems will be protected from the general hazards of the mine 
environment. The installation requirements in this paragraph ensure 
that additional protection will be provided for specific system 
components.
    Paragraph (a)(4), like the proposal, requires that the suppressant 
agent distribution tubing or piping be secured and protected against 
damage, including pinching, crimping, stretching, abrasion, and 
corrosion. No specific comments were received on this aspect of the 
proposal. During the normal mining activity in and around a permanent 
underground diesel fuel storage facility, a fire suppression system can 
become damaged from collisions with mining equipment or from daily 
mining operations. This requirement ensures that fire suppression 
system components are kept in proper working order and that the entire 
system remains ready to discharge fire suppressant to the entire area 
of a permanent underground diesel fuel storage facility.
    Paragraph (a)(5) adopts the requirement from the proposal that fire 
suppression nozzles be protected against the entrance of foreign 
materials.

[[Page 55482]]

No specific comments were received on this aspect of the proposal. The 
nozzles used on multipurpose dry chemical fire suppression systems can 
be as small as \1/8\ of an inch. If material such as mud, coal dust, or 
rock dust enters the nozzle, it can prevent the chemical agent from 
discharging entirely, or alter the pattern and coverage of fire 
suppressant.
    Paragraph (b) of this section of the final rule requires that the 
fire suppression system provide automatic fire detection and automatic 
suppression for all areas within a permanent underground diesel fuel 
storage facility. The proposal would have required automatic fire 
detection and fire suppression for fuel storage tanks, containers, 
safety cans, pumps, electrical panels and control equipment in fuel 
storage areas. The requirement in the final rule responds to 
commenters'' recommendations that automatic fire detection and 
suppression be provided for all areas within a permanent underground 
diesel fuel storage facility enclosure.
    Although the listing or approval generally describes certain areas 
that may pose a fire hazard, it does not specifically identify which 
hazards must be covered by fire suppression. Fire suppression coverage 
for the entire area of a permanent underground diesel fuel storage 
facility is necessary because of the potential fire hazard created by 
numerous ignition and fuel sources. The proposed coverage of only 
certain specific hazards within a diesel fuel storage facility would 
have resulted in other potential hazards not being addressed. Under the 
proposal, it would have been possible for a fire to begin in one area 
of the facility that was not specifically covered by fire suppression. 
Under these circumstances, a fire could be difficult to contain if 
large quantities of leaked diesel fuel are present throughout the 
facility. The final rule requires the entire area of a diesel fuel 
storage facility to be covered because of the likely spread of a fire 
if a diesel fuel leak develops.
    Paragraph (c) of the final rule requires that audible and visual 
alarms to warn of fire or system faults be provided at the protected 
area and at a surface location which is continually monitored by a 
person when personnel are underground. The final rule also requires 
that, in the event of a fire, personnel be warned in accordance with 
the provisions set forth in Sec. 75.1101-23. This requirement is 
intended to provide a means for immediate notification of personnel in 
the area of a permanent underground diesel fuel storage facility when 
the fire suppression system detects a fire or identifies a problem with 
the system. The audible and visual indication of fire detection is 
important because it alerts personnel in and around the area of a 
permanent underground diesel fuel storage facility that a fire exists 
and that a chemical agent is being discharged. The requirement for 
audible and visual indication of fault detection is established in 
order to alert personnel working in and around diesel fuel storage 
facilities that a problem exists with the fire detection system so that 
the defect can be addressed.
    The proposal would have required that audible and visual alarms to 
warn of fire or system faults be provided at the protected area and at 
a surface location which is always staffed when personnel are 
underground who could be endangered by a fire. In addition, the 
proposal would have required that a means also be provided for warning 
all endangered personnel in the event of a fire.
    Several commenters to the proposal expressed concern over this 
requirement, stating that the requirement for visual and audible alarms 
at a surface location would be impractical for many small operators 
because it would result in operators maintaining a monitoring system to 
detect fires. These commenters recommended that fire suppression 
systems be examined regularly to determine system faults, and that 
audible and visual alerts should only be required at locations where 
miners are present. Another commenter stated that mines have become lax 
in responding to fire warnings. One commenter recommended that a formal 
procedure be established to warn personnel in the event of a fire, and 
that this procedure should be submitted to MSHA for approval and be 
included in the mine emergency fire fighting and evacuation plan and in 
the miners'' annual refresher training. Other commenters stated that 
the proposed phrase ``always staffed'' does not ensure that a qualified 
or responsible person will be designated to alert mine personnel 
underground in the event of a fire. One commenter suggested that the 
language ``always staffed'' be changed to ``someone who is qualified.''
    The continual monitoring by a person on the surface of fire 
detection and fire suppression system faults is not a burdensome 
requirement given the chance that a fire or system fault may otherwise 
go unnoticed. The early warning of a fire at a permanent underground 
diesel fuel storage facility is critical, due to the presence of 
numerous ignition sources and large quantities of diesel fuel. If 
communication is not available, fire fighting efforts can be hampered 
and the fire can spread. Also, if a program is not instituted to warn 
of a fire, personnel located in other areas of the mine can be put at 
risk of being cut off from escape. In addition, faults in fire 
suppression systems need to be identified and communicated to 
maintenance personnel so that system defects can be corrected. If an 
automatic fire suppression system is not functioning properly and a 
fire breaks out, it could result in a serious hazard since the fire 
would not be extinguished in its incipient stage. The inspection and 
maintenance requirements for fire suppression systems specified under 
the final rule should ensure the reliability of the system and minimize 
the occurrence of false alarms.
    The final rule responds to commenters by providing flexibility in 
the method used to alert mine personnel that a fire exists at a 
permanent underground diesel fuel storage facility. Under the final 
rule, when a fire is detected, personnel are to be warned in accordance 
with the provisions set forth in existing Sec. 75.1101-23. Section 
75.1101-23 requires that each operator of an underground coal mine 
adopt a program for the instruction of all miners in fire fighting and 
evacuation. The program of instruction is submitted to the appropriate 
MSHA district manager for approval on a mine-by-mine basis. By 
including the requirement for early warning of fires at permanent 
underground diesel fuel storage facility in Sec. 75.1101-23, the final 
rule allows this important communication provision to be developed by 
taking into consideration mine-specific conditions.
    This section of the final rule also requires that a person be 
assigned on the surface whose duties include receiving notification of 
fire detection and alerting underground personnel that a fire has been 
detected. The final rule does not specify any qualification or training 
for the person designated on the surface. However, the instruction of 
all mine personnel, including the designated person staffed at a 
surface location, is a critical element of an early warning fire 
response strategy and is the responsibility of the mine operator under 
Sec. 75.1101-23.
    Paragraph (d) of this section of the final rule requires that the 
fire suppression system deenergize all power to the diesel fuel storage 
facility when actuated except that required for automatic enclosure and 
alarms. This requirement was added to the final rule in response to 
commenters' concerns regarding reignition of fires caused by electrical 
failures. As stated earlier, fire

[[Page 55483]]

suppression systems are designed to suppress fires in their incipient 
stage. If the ignition source and fuel sources remain present after the 
fire suppression system has been actuated, the fire can reignite. 
Shutting off any unnecessary electrical power to the facility will 
remove a potential ignition source and reduce the likelihood that the 
fire will reignite.
    The Ontario accident data for fires on diesel equipment supports 
the need for shutting off ignition sources to prevent reignition. This 
hazard is just as significant for diesel fuel storage facilities, since 
potential electrical ignition sources are present with large quantities 
of diesel fuel. The final rule is also consistent with existing 
Sec. 75.1107-4, which requires that the electric power source to the 
protected equipment be disconnected when the fire suppression system is 
actuated.
    This requirement also applies to any fuel transportation unit 
located in a permanent diesel fuel storage facility that is equipped 
with an electric panel and controls directly connected to an electrical 
power source.
    Paragraph (e) of the final rule, like the proposal, requires that 
fire suppression systems at permanent underground diesel fuel storage 
facilities be equipped with two manual actuators. The final rule 
requires that at least one actuator be located within the fuel storage 
facility and at least one actuator be located a safe distance away from 
the facility in intake air, upwind of the storage facility. The final 
rule is intended to ensure that at least two manual actuators be 
provided in locations that are accessible to mine personnel working in 
or around a permanent diesel fuel storage facility. This requirement is 
similar to the fire extinguisher location requirements for underground 
fuel storage facilities and areas in Sec. 75.1903(b)(1) and (b)(2) of 
the final rule, which provide that at least one portable fire 
extinguisher be located outside of the storage facility or area upwind 
of the facility, in intake air, to enable miners to reach the actuator 
in the event of fire. To allow flexibility in complying with the 
requirements of this paragraph, what constitutes a ``safe distance from 
the facility'' has not been specified in the final rule. The location 
of the actuator outside the facility should be determined based on mine 
conditions and the particular usage of the facility.
    Commenters generally expressed support for this aspect of the 
proposal. One commenter recommended that a requirement be added to 
address manual application of water in lieu of manual actuators when 
sprinkler systems are used. Another commenter suggested that actuators 
be separated from each other, and specifically recommended that a check 
valve be used to ensure that one faulty actuator does not circumvent or 
defeat the use of the other actuator.
    The final rule specifically addresses only requirements for dry 
chemical fire suppression systems, and a water sprinkler type fire 
suppression system would be considered an alternate type of fire 
suppression system under paragraph (a)(1) of this section. As a result, 
the final rule does not adopt the suggestion that an additional 
requirement be added to address manual application when water sprinkler 
systems are used. In addition, the final rule does not include a 
requirement for a check valve between the actuators for fire 
suppression systems. This is considered part of the system design and 
is more appropriately addressed by the system manufacturer and the 
listing or approving nationally recognized independent testing 
laboratory.
    Paragraph (f) of the final rule adopts the requirement from the 
proposal that the fire suppression system remain operational in the 
event of an electrical system failure. No specific comments were 
received on this aspect of the proposal. This requirement is intended 
to ensure that the system will be functional if power from external 
sources is lost. The phrase ``engine shutdown'' has not been adopted 
from the proposal, because the phrase would have applied to fire 
suppression system requirements for unattended diesel- powered 
equipment. Because the final rule does not permit the operation of 
unattended diesel-powered equipment, this phrase is no longer 
necessary.
    Paragraph (g) adopts the requirement from the proposal that 
electrically operated detection and actuation circuits be monitored and 
provided with status indicators showing power and circuit continuity. 
The final rule also requires that automatic detection systems be 
provided with a means to indicate the functional readiness status of 
the detection system. This paragraph requires that the fire suppression 
system provide a means of notifying miners and maintenance personnel of 
the functional readiness status of both the detection and actuation 
circuit and the power source. This paragraph also requires that 
automatic systems not electrically operated provide a means of 
notifying the operator or maintenance person of the functional 
readiness of the system.
    This requirement is included in the final rule to ensure the 
continuity of electrical systems used to detect faults on fire 
suppression systems. This requirement will serve to alert miners and 
maintenance personnel when a fire suppression system is not in a state 
of readiness due to an electrical system fault. The continuity of the 
electrical system used to detect fires and actuate the system is 
important since an automatic system is based on early detection and 
automatic actuation.
    One commenter to the proposal stated that the fire suppression 
system should also be protected as specified in Sec. 75.1101-17, which 
requires that each dry powder chemical system be adequately sealed to 
protect all components of the system from moisture, dust, and dirt.
    The protection of the fire suppression system components from 
moisture and dust is adequately addressed by the requirements of 
paragraphs (a)(3), (a)(4) and (a)(5) of this section of the final rule. 
In addition, the listing or approval typically includes requirements 
for a dust shield and checks of the powder for dryness.
    Paragraph (h) of the final rule adopts the requirement from the 
proposed rule that each fire suppression system be tested and 
maintained in accordance with the manufacturer's recommended inspection 
and maintenance program and as required by the nationally recognized 
independent testing laboratory listing or approval, and be visually 
inspected at least once each week by a person trained to make such 
inspections.
    The proposed rule would have required each fire suppression device 
to be visually inspected at least once each week by a person qualified 
to make such inspections. The proposal also would have required that 
each fire detection device be tested and maintained in accordance with 
applicable requirements in Sec. 75.1100.
    Commenters to the proposal generally expressed support for 
maintenance of fire suppression systems installed at permanent 
underground diesel fuel storage facilities. A number of commenters, 
however, recommended that a maintenance program specifically designed 
for fire suppression systems be developed at each mine. One commenter 
to the proposal expressed concern over the requirement for weekly 
visual inspections of fire suppression systems at permanent underground 
diesel fuel storage facilities. This commenter recommended that there 
be frequent functional testing of the suppression systems to ensure 
that lines are not blocked or pinched. Another commenter stated that 
the proposal did not specify the types of tests that should be 
conducted on fire suppression systems at permanent underground

[[Page 55484]]

diesel fuel storage facilities. Other commenters expressed concern over 
the frequency of tests and inspections. These commenters recommended 
that detailed inspections and functional tests be conducted 
semiannually or quarterly. One commenter recommended that fire 
suppression systems be treated in the same manner as portable fire 
extinguishers and that inspections be conducted once a week and 
physically tested twice a year.
    Under the final rule, the weekly visual inspection is not intended 
to be an in-depth examination. The weekly visual inspection is intended 
to be a quick check to verify that there are no obvious defects, such 
as disconnected hose lines or altered nozzles. An in-depth inspection 
takes place as part of the manufacturer's recommended testing and 
inspection procedure also required under the final rule. Fire 
suppression system manufacturers are most familiar with the design and 
operation of their systems and are best able to identify the components 
that need maintenance, the type of maintenance needed, and the 
frequency of maintenance. Adequate maintenance is essential because of 
the importance of these systems in fire protection. The maintenance and 
testing requirements for fire suppression systems are in addition to 
the requirement set forth for a weekly visual inspection.
    The manufacturer's inspection and maintenance procedures are 
spelled out in great detail in the manufacturer's manual and include 
the recommended inspection intervals, which depend on the environment 
in which the system operates. In addition, these inspection and 
maintenance procedures are evaluated as part of the system's approval 
or listing by a nationally recognized independent testing laboratory.
    This paragraph is identical to the requirement in Sec. 75.1107-
16(a). As stated earlier, the fire suppression system requirements in 
Secs. 75.1107-3 through 75.1107-16 cannot be directly applied to diesel 
equipment because the fire hazards presented by diesel fuel are 
different from those on electric-powered equipment, due to the close 
proximity of large quantities of diesel fuel to potential ignition 
sources.
    Also modified in this paragraph is the replacement of the term 
``device'' with the term ``system''. This was done because MSHA intends 
that the whole system be inspected, not just individual components of a 
system.
    A person ``trained'' to perform the inspections and tests required 
by paragraph (h) of this section of the final rule is not required to 
be a qualified person under Sec. 75.1915. However, the final rule 
intends that the person performing tests and inspections of fire 
suppression systems have sufficient knowledge to determine whether a 
fire suppression system is functioning properly. MSHA anticipates that 
since fire suppression systems are common to both electric and diesel 
equipment, the mine operator will work with either the fire suppression 
system manufacturer or distributor to ensure that persons responsible 
for the maintenance of fire suppression systems are adequately trained.
    Paragraph (i) of the final rule establishes recordkeeping 
requirements for the inspection and maintenance requirements for fire 
suppression systems set forth in paragraph (h), and requires that 
persons performing inspections and tests of these systems record 
results of tests and inspections only when a system does not meet the 
installation or maintenance requirements of this section. Under these 
circumstances, the person performing the inspection or test is required 
to indicate the fuel storage facility where the fire suppression system 
did not meet the installation or maintenance requirements of this 
section, the defect found, and the corrective action taken. The final 
rule also requires that these records be kept either manually or 
electronically in a secured manner that is not susceptible to 
alteration. In addition, the final rule requires that records be 
maintained at a surface location at the mine for one year and made 
available for inspection by an authorized representative of the 
Secretary and by miners representatives.
    The proposal would have required that a record be kept of all of 
the inspections of fire suppression systems and maintained at an 
appropriate location for each fire suppression device. One commenter to 
the proposal recommended that the records required by this section be 
made available to all interested parties and that this information be 
centrally located on the surface of the specific mine.
    Office of Management and Budget guidance comments directed MSHA to 
reexamine the recordkeeping requirements in the proposal and 
recommended that the final rule require paperwork that was the least 
burdensome necessary. MSHA has done so, and the final rule does not 
adopt the proposal that all fire suppression system test and 
maintenance results be recorded. In response to commenters and 
consistent with other provisions of the final rule, paragraph (i) 
requires that records of inspections and tests be made only when a fire 
suppression system does not meet the installation or maintenance 
requirements of this section. This requirement is important because if 
a fire suppression system does not meet its listing or approval, the 
defect can be of a nature and seriousness that the system can fail when 
a fire begins. This requirement is intended to ensure that records are 
maintained and made available to interested parties when a defect is 
found, and that the appropriate level of mine management is made aware 
of defects requiring attention.
    The final rule does not specify a particular way of recording the 
test and maintenance data, only that it be located at the surface of 
the mine. The records of the inspections and tests must be made in a 
secure media not susceptible to alteration. A detailed discussion of 
the subject of acceptable record books and electronic records can be 
found under the heading ``Recordkeeping Requirements'' in the General 
Discussion section of this preamble.
    The final rule does not adopt the requirement from the proposed 
rule that records of inspections be maintained at an appropriate 
location near each fire suppression system. Instead, paragraph (i)(3) 
of this section of the final rule establishes the requirement 
recommended by a commenter that records of inspections and tests be 
maintained at a surface location at the mine. Storing records on the 
surface at the mine makes them more accessible to interested parties. 
Also in response to commenters, the final rule provides access not only 
to miners representatives but to authorized representatives of the 
Secretary. This provision ensures that test and inspections of fire 
suppression systems are being made and, when a defect is found, 
corrective action is taken.
    Paragraph (j) adopts the proposed requirement that all miners 
normally assigned in the active workings of the mine be instructed 
about the hazards inherent to the operation of fire suppression 
systems, and where appropriate, the safeguards available for each 
system. This requirement is intended to ensure that all miners working 
in areas where fire suppression systems operate are instructed in any 
inherent hazards and necessary precautions associated with the 
operation of these systems. The final rule modifies the proposal in 
that the term ``device'' has been replaced by the term ``system'' to 
clarify that this requirement applies to the entire system rather than 
to system components.
    One commenter to the proposal agreed with the requirement that 
miners be trained in the hazards and safeguards

[[Page 55485]]

of fire suppression systems, but recommended that such training be 
incorporated in the annual refresher training required under existing 
Sec. 75.1101-23 for the program of instruction, location and use of 
fire fighting equipment. Under the final rule, it is anticipated that 
the instruction on the hazards of fire suppression systems required by 
this paragraph will be part of the Sec. 75.1101-23 instruction.
Section 75.1913--Starting Aids
    This section addresses the storage and use of volatile fuel 
starting aids for diesel-powered equipment. The requirements of the 
final rule are similar to the requirements contained in the proposal, 
with some minor modifications. This section places limitations on the 
use and storage of volatile fuel starting aids underground, to minimize 
the risks of fire or explosion. Under the final rule, volatile fuel 
starting aids must be used in accordance with recommendations of the 
starting aid manufacturer, the engine manufacturer, and the machine 
manufacturer. The final rule also includes requirements for the storage 
of volatile fuel starting aids, and prohibits the use of starting aids 
under certain circumstances, such as in areas where permissible 
equipment is required or where 1.0 percent or greater concentration of 
methane is present. Connection of compressed oxygen or compressed 
flammable gases to diesel air-start systems is also prohibited.
    The Diesel Advisory Committee recognized that improper storage and 
handling of starting aids could present fire and explosion hazards in 
underground coal mines. The Committee therefore recommended that MSHA 
regulate the storage and use of starting aids. The proposed rule set 
forth limitations on the use of starting aids, to minimize the hazards 
associated with their use in the underground coal mine environment. The 
requirements of the final rule reflect MSHA's determination that 
volatile fuel starting aids can be safely used underground if 
appropriate precautions are taken.
    Volatile fuel starting aids, normally ethyl ether, facilitate the 
starting of diesel engines in cold temperatures. In very cold weather 
the compression ignition of diesel engines cannot easily reach the high 
temperature necessary to ignite diesel fuel. This makes it difficult, 
and in some cases impossible, to start the engine without special 
measures, such as the use of volatile fuel starting aids. Volatile fuel 
starting aids sprayed into a cold diesel engine help to start the 
engine because they ignite at a much lower temperature than diesel 
fuel. Starting aids that are ignited in a diesel engine will both heat 
up the cylinder walls of the engine and start the engine spinning, 
resulting in easier ignition of the diesel fuel.
    The use and storage of volatile fuel starting aids in underground 
coal mines present safety hazards, due to the starting aids' high 
volatility. When these substances are stored or used improperly, they 
can present a very real danger of fire or explosion, particularly in 
the underground coal mine environment.
    Commenters were divided on whether the use of starting aids should 
be permitted in underground coal mines. Some commenters recommended a 
complete prohibition of the use of volatile fuel starting aids 
underground, stating that starting aids are extremely flammable, have a 
very low flash point, and can be ignited by any source of heat in the 
mine. These commenters believed that there were already numerous 
potentials for fire in the underground coal mine environment, and that 
permitting the use of starting aids would introduce another unnecessary 
hazard into that environment. Some commenters believed that starting 
aids were used at some mines as a substitute for effective maintenance 
of diesel engines, and that a properly maintained engine should be able 
to start on its own, without the boost that a starting aid provides.
    Other commenters advocated allowing the use of starting aids but 
strictly controlling their use. Several commenters stated that starting 
aids were currently being used safely and effectively in their mines, 
and that any hazards arising from their use could be controlled by 
careful handling. These commenters stated that proper maintenance of 
diesel engines does not prevent starting difficulties in cold 
temperatures. One commenter observed that air temperatures at mines 
located at elevations of 9,000 or 10,000 feet can fall well below 
0 deg. F. Several commenters observed that a diesel-powered machine 
that has been shut down and has been sitting in cold weather, such as 
over a weekend, can be virtually impossible to start without the use of 
a starting aid.
    Some of the commenters who favored prohibiting the use of volatile 
fuel starting aids underground stated that starting aids sometimes were 
used as a substitute for effective maintenance. Although an engine that 
has not been properly maintained could in some cases be started more 
easily with starting aids, this fact alone does not compel the 
prohibition of volatile fuel starting aids in underground coal mines. 
The final rule requires regular maintenance and testing of diesel-
powered equipment, designed to ensure that the equipment is kept in 
good operating condition. Compliance with these requirements should 
eliminate any need to use starting aids as a replacement for effective 
equipment maintenance.
    Paragraph (a) of this section requires that volatile fuel starting 
aids be used in accordance with the recommendations of the starting aid 
manufacturer, the engine manufacturer, and the machine manufacturer. 
The proposed rule would have required that volatile fuel starting aids 
be used in accordance with the specific recommendations in the engine 
manufacturer's maintenance and operations manual.
    Several commenters noted that the written documentation from 
machine or engine manufacturers does not always address correct use of 
volatile fuel starting aids, and expressed their concern that starting 
aids could create serious hazards if not used in conformance with 
specific recommendations. In response to these comments, the final rule 
provides that starting aids must also be used in accordance with the 
recommendations of the starting aid manufacturer, ensuring that mine 
operators will at a minimum be guided by those instructions. Starting 
aid manufacturers are already required by Occupational Safety and 
Health Administration regulations to develop Material Safety Data 
Sheets (MSDS) for their products. To comply with this provision the 
mine operator should obtain an MSDS and any other product safety and 
use information prepared by the starting aid manufacturer on the safe 
use of that particular starting aid, and use the starting aid in 
accordance with those instructions.
    Because engine and machine manufacturers are in the best position 
to determine whether volatile fuel starting aids can be safely and 
effectively used with a particular engine or machine, the final rule 
also requires mine operators to use starting aids in accordance with 
any available recommendations from the engine and machine manufacturers 
on the safe use of starting aids. This requirement recognizes that 
volatile fuel starting aids can damage engine or machine components and 
result in the failure of machine safety devices or increase exhaust 
emissions. For example, a buildup of the starting aid in intake or 
exhaust components could result in an explosion. Use of starting aids 
in accordance with the recommendations of engine and machine 
manufacturers will minimize

[[Page 55486]]

any safety hazards and avoid damage to the engine or machine, such as 
damage to intake or exhaust components, especially on permissible 
equipment.
    Although the final rule is not intended to prohibit the use of 
starting aids if such information has not been developed by the machine 
or engine manufacturer, MSHA encourages diesel-powered engine and 
machine manufacturers who do not already do so to develop 
recommendations on the use of volatile fuel starting aids with the 
engines and machines they produce.
    Paragraph (b) requires that containers of volatile fuel starting 
aids be conspicuously marked to indicate their contents. This paragraph 
further requires that containers of volatile fuel starting aids that 
are not in use be stored in metal enclosures that are used only to 
store starting aids. The metal enclosures themselves are required to be 
conspicuously marked, secured, and protected from damage.
    The requirement that starting aid containers be conspicuously 
marked was not included in the proposal, but has been incorporated in 
the final rule in response to commenters' concerns over the serious 
dangers that could result if starting aids containers were damaged in 
any way. The container marking requirement is intended to prevent 
inadvertent damage to containers by ensuring that mine personnel are 
aware of the containers' contents. Labels that are affixed to the 
starting aid can by the starting aid manufacturer will satisfy the 
requirement for container marking.
    The final rule also requires that enclosures for containers of 
starting aids be made of metal, marked, secured, and protected from 
damage, and used only for the storage of starting aids. The proposed 
rule would have required only that starting aids be stored in a fire 
proof enclosure when not in use. The final rule includes additional 
requirements to address commenters' concerns that starting aid 
containers could be inadvertently damaged, resulting in the 
unintentional release of the highly flammable starting aid. These 
additional requirements are similar to the requirements in the final 
rule that apply to safety cans containing diesel fuel that are 
transported on vehicles. Because both volatile fuel starting aids and 
diesel fuel present a possible fire hazard, the final rule imposes 
similar precautions for the handling and storage of these substances. 
The final rule also prohibits any other items, such as tools, from 
being stored with volatile fuel starting aids. This prohibition 
responds to commenters' concerns that containers of volatile fuel 
starting aids could be damaged through contact with other items, 
resulting in the release of the starting aid and the creation of a 
potentially hazardous situation.
    Some commenters noted that the term ``fire proof enclosure'' used 
in the proposed rule was not defined anywhere in the regulations, and 
recommended the substitution of the term ``noncombustible''. Other 
commenters opposed the use of the term ``noncombustible'' because of 
their concern that a container that is simply noncombustible may not be 
substantial enough to protect starting aid containers. MSHA agrees with 
commenters who believe that the term ``fire proof'' is ambiguous, and 
also with commenters who oppose the substitution of the term 
``noncombustible'' for the term ``fire proof'' because containers that 
are ``noncombustible'' may not be sufficiently durable. The final rule 
therefore requires that containers of starting aids be stored when not 
in use in metal enclosures, which are not only noncombustible but also 
sturdy enough to protect the starting aid containers that are stored 
there.
    Paragraph (c) adopts the requirements of the proposal, and imposes 
specific restrictions on where and under what circumstances volatile 
fuel starting aids may be used in underground coal mines, to minimize 
any hazards presented by their use. Paragraph (c)(1) prohibits volatile 
fuel starting aids from being taken into or used in areas where 
permissible equipment is required. Volatile fuel starting aids can 
create flames that flame arresters, which are designed to provide 
protection against methane ignitions, cannot stop. Use of volatile fuel 
starting aids in an area where permissible equipment is required could 
lead to an ignition of any methane in the area. Use of starting aids in 
those areas is therefore forbidden in the final rule.
    Paragraph (c)(2) prohibits the use of volatile fuel starting aids 
in the presence of open flames or burning flame safety lamps, or when 
welding or cutting is taking place. As noted by several commenters, 
vapors from volatile fuel starting aids are easily ignited. The final 
rule requires that volatile starting aids be kept away from the 
potential ignition sources of open flames or welding or cutting. 
Starting aids are also prohibited in the presence of burning flame 
safety lamps. The gauze in a flame safety lamp, although safe for use 
in the presence of methane, will not prevent the propagation of the 
flame by the ether vapors given off by the starting aid. The final rule 
is intended to prohibit these ignition sources in the immediate 
vicinity of any area where volatile fuel starting aids are being used.
    Paragraph (c)(3) adopts the proposal to prohibit the use of 
volatile fuel starting aids in any area of the mine where 1.0 percent 
or greater concentration of methane is present. This requirement 
minimizes the possibility that starting aid vapors that have 
accidentally been ignited would spread to methane in the surrounding 
area. Permissible equipment may not prevent a flashback of fire that 
could ignite a methane atmosphere.
    The proposed rule would have prohibited the use of starting aids in 
areas of the mine where 1.0 percent or greater of methane is detected. 
The final rule has been clarified to reflect that volatile fuel 
starting aids must not be used where 1.0 percent or greater of methane 
is ``present'', thereby placing on the mine operator the responsibility 
of ensuring that methane levels are within acceptable limits before 
volatile fuel starting aids are used.
    Paragraph (d) imposes limitations on the use of compressed gases as 
starting aids for diesel-powered engines. The final rule adopts the 
proposal's prohibition of the connection of compressed oxygen or 
compressed flammable gases to diesel air-start systems. Commenters 
generally supported this restriction. The use of compressed oxygen in 
the presence of engine lubricants, which are normally in diesel air 
start-systems, presents an immediate danger of a fire. The final rule 
consequently forbids the use of compressed oxygen for this purpose. 
Additionally, the introduction of compressed flammable gases into the 
machine's compressed air system presents not only the same fire hazard 
as compressed oxygen, but also a danger of explosion from flammable 
gases being placed in close proximity to possible sparks from the 
diesel engine. The final rule therefore also prohibits the use of 
compressed flammable gases in diesel air-start systems. Nonflammable 
gases, such as nitrogen, are permitted for this purpose.
Section 75.1914 Maintenance Of Diesel-Powered Equipment
    Section 75.1914 sets forth maintenance, repair and testing 
requirements for diesel-powered equipment, and also indicates the level 
of training or qualification a person must have to perform these 
important tasks. The rule generally requires that diesel-powered 
equipment be maintained in safe and approved condition, and 
specifically requires weekly equipment examination, weekly testing and 
evaluation of gaseous

[[Page 55487]]

emissions, flushing and draining of scrubbers, and changing of air 
filters. A person must be qualified under Sec. 75.1915 to perform 
maintenance and repairs of approved and other specified features on 
diesel-powered equipment, and to conduct weekly equipment tests and 
examinations. However, the rule allows other functions required under 
this section to be performed by a person not qualified under 
Sec. 75.1915, so long as the person has been trained in the task.
    This section of the final rule recognizes that effective equipment 
maintenance is an indispensable element in reducing the health and 
safety hazards of diesel-powered equipment, and that adequate training 
of maintenance personnel is an important part of ensuring that such 
work is performed correctly. The purpose of the requirements of this 
section is to ensure that diesel-powered equipment is properly 
maintained so that it does not deteriorate through neglect, abuse, or 
normal use and result in a safety or health hazard to miners.
    Virtually all commenters to the proposed rule supported the need 
for maintenance requirements for diesel-powered equipment used in 
underground coal mines. Commenters agreed that regular maintenance and 
routine examination of equipment is essential, as the performance of 
even the best-designed equipment will decline over time without proper 
maintenance. Inadequate maintenance of diesel equipment can result in 
the creation of fire or explosion hazards, and the levels of harmful 
gaseous and particulate components in diesel exhaust can increase when 
equipment is poorly maintained.
    Several commenters to the proposed rule provided specific examples 
of the problems and hazards that result when maintenance personnel are 
poorly trained. Some commenters stated that inadequately trained 
personnel frequently failed to maintain diesel equipment in approved 
condition, causing the engines to deteriorate and resulting in 
increased levels of harmful exhaust gases. Commenters also reported 
that untrained persons were more likely than properly trained persons 
not only to allow safety systems to malfunction in the first place, but 
also to bypass the malfunctioning safety system in order to continue 
operating the machine, rather than to repair the system.
    Paragraph (a) of this section retains the language of the proposed 
rule and requires that all diesel-powered equipment used in underground 
coal mines be maintained in approved and safe condition or removed from 
service. Several commenters recommended that the word ``approved'' be 
deleted, in the belief that it would be acceptable to use permissible 
equipment in non-approved condition when the machine was being operated 
in an outby location.
    Paragraph (a) of the final rule prohibits the use of diesel 
equipment that is not in approved and safe condition. This prohibition 
includes the operation of permissible diesel-powered equipment in outby 
areas when an approved feature has been disabled. There are several 
reasons that this requirement has been adopted in the final rule. Many 
types of approved diesel equipment are extremely mobile, moving easily 
from areas of the mine where permissible equipment is required to areas 
where it is not, and there is nothing to distinguish a piece of diesel-
powered equipment that has not been maintained in permissible condition 
from one that has. Both bear MSHA approval plates. Additionally, 
temperature sensors and other safety system components on diesel-
powered equipment can be permanently damaged by exposure to high 
temperature exhaust gas when the equipment is not maintained in 
approved condition and a safety system is bypassed. The final rule 
therefore requires that equipment be maintained not only in safe 
condition but also in approved condition.
    Paragraph (b) requires that maintenance and repairs of approved 
features, and the features required by Secs. 75.1909 and 75.1910, be 
made only by a person qualified under Sec. 75.1915. The final rule 
retains the concept of the proposal that the maintenance and repair of 
certain features of diesel-powered equipment be performed by a 
qualified person. The majority of commenters supported mandatory 
training and some form of qualification for those individuals 
performing these functions because it would help to ensure that diesel 
equipment is adequately maintained and kept in good operating 
condition. The Diesel Advisory Committee also recommended that 
qualified persons be responsible for the more complicated systems on 
the machine, such as the approved components.
    A more extensive level of training is needed to ensure that persons 
working on more complex equipment features are adequately skilled. 
Additionally, MSHA machine approval requirements are largely 
performance-oriented, and equipment manufacturers consequently have 
significant latitude in designing their equipment to satisfy MSHA's 
permissibility requirements. Because a variety of equipment designs 
could accomplish the safety objectives mandated by an MSHA approval, 
approved equipment does not always conform to easily recognizable 
standards, and the ability to perform maintenance and repair work on 
the more complex features of diesel-powered equipment requires a 
comprehensive understanding of the equipment's design. The final rule 
therefore adopts the requirement of the proposal that persons 
performing work on certain specified features of diesel-powered 
equipment be qualified under Sec. 75.1915, which requires completion of 
a training program developed by the mine operator.
    The proposed rule specified only that ``approved features'' must be 
maintained and repaired by a person qualified under Sec. 75.1915, and 
did not include within its scope ``features required by Secs. 75.1909 
and 75.1910'' as does paragraph (b) of the final rule. However, the 
scope of this requirement under the final rule is essentially the same 
as it would have been under the proposed rule. Under the proposed rule, 
all nonpermissible equipment, with the exception of a limited class of 
light-duty equipment and stationary unattended equipment, would have 
been subject to a whole machine approval under part 7. Because the 
final rule does not require whole machine approval of nonpermissible 
equipment, and instead requires that this equipment be provided with 
the safety features set forth in Secs. 75.1909 and 75.1910, essentially 
the same features must be maintained and repaired by a qualified person 
under the final rule as would have been required under the proposal.
    Paragraph (c) of the final rule requires that the water scrubber 
system on diesel-powered equipment be drained and flushed, by a person 
who is trained to perform this task, at least once during each shift 
that the equipment is operated. The proposed rule contained the same 
requirement for flushing scrubbers, but did not specify what type of 
training was required for the person performing the task.
    The rationale behind the requirement for flushing and draining is 
that routine cleaning of scrubbers, which cool equipment exhaust gases 
and act as flame arresters, is essential to prevent a buildup of solid 
exhaust particles and sludge in the scrubber. This condition can 
eventually block internal passages of the scrubber, impairing the 
scrubber's effectiveness and compromising safety in the mine. The 
Advisory Committee also recommended that MSHA require mine operators to 
change scrubber water on a regular basis.
    Commenters generally supported regular draining and flushing of

[[Page 55488]]

scrubber systems, although some commenters questioned whether the rule 
should specify the point in the shift when draining and flushing must 
be done. Commenters also questioned what level of qualification was 
necessary as a prerequisite to performing this task. The consensus of 
the Advisory Committee was that routine maintenance, such as changing 
scrubber water, could be performed by a person who is not certified, 
and that task training would be sufficient in those situations.
    MSHA agrees that draining and flushing of the scrubber is a 
relatively straightforward task, and that the comprehensive training 
required for qualification under Sec. 75.1915 is unnecessary to ensure 
that persons perform this task competently. The final rule therefore 
clarifies MSHA's intention that scrubber draining and flushing need not 
be done by a person qualified under Sec. 75.1915, only that the person 
be trained to perform the task. MSHA expects that the draining and 
flushing of the water scrubber system will typically be performed by 
the machine operator.
    In response to the proposed requirements for scrubber maintenance, 
some commenters stated that the final rule should specify that scrubber 
systems must be drained and flushed at the beginning of the shift. 
These commenters were concerned that if the rule did not specifically 
require draining and flushing at the beginning of the shift, MSHA could 
not issue a citation for violation of this standard until the end of 
the shift, making enforcement difficult. Other commenters advocated 
that the final rule require the scrubber system to be drained and 
flushed at the end of the shift, allowing mine operators to perform the 
task as part of the routine maintenance to prepare the machine for the 
next shift.
    MSHA has carefully considered the comments on this issue, and has 
chosen to retain the language of the proposed rule in the final rule, 
which simply requires scrubber systems to be flushed and drained once 
during each shift that the equipment is operated, without specifying 
when during the shift the task must be performed. This is consistent 
with MSHA's intention to afford mine operators reasonable flexibility 
in performing the maintenance required by the final rule. However, MSHA 
recommends that mine operators perform scrubber maintenance at about 
the same point during every shift, thereby ensuring that scrubbers are 
flushed and drained every 8 to 10 hours (depending on the length of the 
shift) during the equipment's operation.
    Paragraph (d) requires that the intake air filter be replaced or 
serviced either when the intake air pressure drop device indicates that 
it is necessary, or when the engine manufacturer's maximum allowable 
air pressure drop level is exceeded. The final rule also requires that 
this replacement or servicing be done by a person who is trained to 
perform the task.
    Maintenance of diesel machine air filters is an important element 
of overall equipment maintenance. Air filters screen the air taken in 
by the machine for combustion. Over time, the filters load up with dust 
and dirt, restricting air flow and making the engine work harder to 
pull in the same amount of air. As the engine works harder, greater 
quantities of engine emissions are produced, adversely affecting the 
quality of the air that miners breathe. Research and experience 
indicate that air restrictions have a negative effect on emission 
generation, specifically carbon monoxide and diesel particulate.
    The proposed rule would have required filter replacement or 
servicing when the filter was ``dirty'' as well as when the machine's 
intake air pressure drop device indicated that it was necessary. The 
proposed rule would not have required, as does the final rule, filter 
maintenance when the manufacturer's maximum allowable air pressure drop 
level is exceeded.
    Commenters generally supported the requirements of this paragraph, 
and several stated that dirty air filters were frequently to blame when 
engines began to produce increased levels of carbon monoxide. However, 
several commenters objected to mandatory filter replacement and 
servicing when the filter was ``dirty'', pointing out that the term 
``when dirty'' was ambiguous. Commenters stated that air filters catch 
dirt continually, and are therefore ``dirty'' to some degree at all 
times. MSHA agrees with commenters on this issue, and has concluded 
that the use of the term ``when dirty'' could create uncertainty for 
mine operators in complying with the provision. The requirement that 
filters be replaced or serviced ``when dirty'' has therefore not been 
adopted in the final rule.
    The final rule does adopt the requirement of the proposed rule that 
air filters be replaced or serviced when the intake air pressure device 
indicates that it is necessary. Intake air pressure devices monitor the 
air pressure across the filter. As the air filter loads up with dust 
and dirt the pressure drop across the filter will increase, and at a 
certain point the intake air pressure device will signal that the 
filter is sufficiently blocked by dirt to require servicing or 
replacement.
    Not all types of diesel-powered equipment are presently equipped 
with intake air pressure devices. Under the proposed rule, air filters 
without air pressure devices would have been required to be changed or 
serviced ``when dirty''. However, as discussed above, that provision 
has not been included in the final rule. One commenter to the proposed 
rule stated that service indicators specified by the manufacturer are 
sufficient for determining when an air filter should be changed. A 
service indicator is simply the manufacturer's specification of the 
drop in pressure across the air filter, reflected by the air pressure 
gauge on the machine, indicating that the air filter must be serviced 
or replaced. MSHA agrees that service indicators provide an objective 
and measurable method of determining the need for air filter servicing 
for machines without intake air pressure devices. The final rule has 
therefore been modified to provide that air filters must be replaced or 
serviced when the engine manufacturer's maximum allowable air pressure 
drop level is exceeded.
    The proposal did not specify the level of training or qualification 
required for the person performing air filter maintenance under this 
paragraph, and commenters questioned whether MSHA intended that this 
task be performed by a person qualified under Sec. 75.1915. Commenters 
generally stated that air filter maintenance did not need to be 
conducted by a qualified person, only by someone who has been trained 
to perform the task. This view is consistent with the consensus of the 
Advisory Committee that simple maintenance activities, such as changing 
air filters, could be performed by miners who are not qualified or 
certified. Accordingly, the final rule specifies that air filter 
maintenance must be performed by a person who has received training in 
the task.
    Paragraph (e) requires that mobile diesel-powered equipment that is 
to be used during a shift be visually examined by the equipment 
operator before being placed in operation, and that equipment defects 
that affect safety be reported to the mine operator. This requirement 
is identical to that of the proposed rule, and was supported by 
commenters.
    MSHA intends that the examinations required under this paragraph 
consist of the equipment operator conducting a check of the equipment 
before operating it to verify that the machine has no obvious safety 
defects, such as fuel leaks, loose batteries, or accumulations of 
combustible materials on the

[[Page 55489]]

machine. The language of the final rule has been changed slightly to 
require that the equipment be ``visually examined'' rather than 
``inspected'', to better convey the nature of the examination. Such an 
examination will provide a regular check on some of the more 
conspicuous equipment problems. This paragraph also requires that 
observed defects be reported promptly to the mine operator, which could 
be a responsible management official, such as a superintendent or 
foreman. The word ``promptly'' has been included in the final rule to 
clarify that safety defects observed during this check should be 
directed to a responsible management official in a timely manner.
    Paragraph (f) provides that all diesel-powered equipment must be 
examined and tested weekly by a person qualified under Sec. 75.1915. 
Commenters generally agreed with the concept of mandatory equipment 
examination at regular intervals, although several commenters stated 
that only diesel equipment that was in use should be subject to 
required examinations, advocating revision of the rule to reflect that 
only equipment ``in service'' is subject to weekly examination.
    Although MSHA understands the basis for these commenters' concerns, 
MSHA has concluded that inserting the term ``in service'' in the final 
rule could be misinterpreted by some mine operators to exclude 
equipment from the weekly examination requirement that the Agency does 
not intend to exclude. For example, some operators may consider 
equipment to be out of service if it has not been operated for an 
extended period, even though the equipment remains in the mine and 
could be operated at any time. MSHA takes a very broad view of what 
equipment is ``in service,'' regarding all equipment not located in 
maintenance shops or surface storage areas as being ``in service'' and 
subject to weekly examination and testing. MSHA has therefore not 
adopted the change advocated by commenters.
    Although commenters supported the concept of regular examination 
and testing of diesel-powered equipment, there was no clear consensus 
on how regularly equipment must be examined. A few commenters who 
raised the issue of the frequency of required equipment examinations 
referred to maintenance schedules for diesel-powered equipment in place 
at their mines, with examination intervals of one week, two weeks, or 
every 150 hours of equipment operation. Other commenters stated that 
examination requirements for diesel- powered equipment should be 
similar to those for electrical equipment. The latter comment is 
consistent with the unanimous recommendation of the Advisory Committee 
that diesel-powered equipment be maintained on the same basis as 
electrical equipment.
    MSHA has concluded that testing and examination of diesel-powered 
equipment on a weekly basis will ensure that equipment is being 
maintained in safe and healthful condition. Weekly examination of 
electrical equipment in underground coal mines has been required and 
has served as an effective check for adequate equipment maintenance for 
more than 20 years. Weekly examinations have consequently become an 
accepted element of routine equipment maintenance in the coal mining 
industry. Diesel equipment and electrical equipment in the underground 
coal mine environment present many of the same hazards. Paragraph (f) 
therefore provides for weekly testing and examination of diesel-powered 
equipment by a person qualified under Sec. 75.1915.
    Several commenters stated that the weekly examinations under 
paragraph (f) should be required only for approved components. Neither 
the proposed rule nor the final rule contains this limitation. The 
proposal would have specified that the weekly examinations be conducted 
in accordance with approved checklists, which are lists developed, with 
the assistance of MSHA, by an equipment manufacturer who is seeking 
MSHA approval. The proposal would have required fully assembled machine 
MSHA approval of all diesel-powered equipment, except for a ``limited 
class'' of light-duty nonpermissible equipment and stationary 
unattended equipment. The final rule requires full machine approval 
only for permissible equipment; nonpermissible equipment must only be 
provided with an approved engine. MSHA nonetheless believes that 
certain machine features, although not subject to MSHA approval, should 
be inspected as part of the regular examination.
    Paragraph (f)(1) requires that examinations and tests be conducted 
in accordance with approved checklists and manufacturers' maintenance 
manuals. These checklists are to be used in conjunction with checklists 
and instructions included in manufacturers' maintenance manuals.
    Commenters supported the use of checklists for examinations and 
tests of diesel-powered equipment. One commenter advocated that 
maintenance requirements be stated in general terms to accommodate new 
equipment design and improved technology in the future. MSHA agrees 
with this comment, and the use of equipment-specific permissibility/
approval checklists and equipment manufacturers' maintenance manuals 
should achieve this result. MSHA would also consider a mine operator to 
be in compliance with this provision if the operator developed its own 
checklist format based on and consistent with the manufacturers' 
maintenance manuals.
    Equipment manufacturers, with the assistance of MSHA, currently 
develop such checklists as part of the MSHA approval process. These 
checklists are designed to provide specific guidance to mine operators 
in verifying that approved equipment is in approved condition. 
Permissibility checklists are used to determine whether maintenance or 
repair is needed to bring the equipment back into approved condition; 
manufacturers' maintenance manuals complement these checklists by 
providing mine operators with specific instructions on how to conduct 
the necessary maintenance or repair. MSHA intends that the approved 
checklists referred to in this paragraph for diesel-powered equipment 
under part 7 will be similar to the permissibility checklists used for 
part 36-approved machines.
    Commenters supported the use of checklists for examinations and 
tests of diesel-powered equipment. One commenter advocated that 
equipment maintenance requirements be stated in general terms to 
accommodate new equipment design and future technological improvements. 
MSHA believes that the use of equipment-specific permissibility/
approval checklists should achieve this result, and has included 
language in the final rule that provides for the use of equipment-
specific manufacturers' maintenance manuals in conjunction with the 
approved checklists in conducting necessary maintenance. MSHA would 
also consider a mine operator to be in compliance with this provision 
if operators developed their own checklist formats based on and 
consistent with the manufacturer's maintenance manuals.
    Paragraph (f)(2) requires that persons performing weekly 
examinations and tests of diesel-powered equipment under this paragraph 
shall make a record when the equipment is not in approved or safe 
condition. The record must include the equipment that is not in 
approved or safe condition, the defect found, and the corrective action 
taken. This requirement has been adopted with modification from the 
proposed rule. Under the proposed rule, a record of all weekly 
equipment examinations would have been required, and recordkeeping

[[Page 55490]]

would not have been limited to those examinations that disclosed a 
defect. Under the final rule the recordkeeping burden has been reduced, 
consistent with efforts to reduce the paperwork burdens placed on the 
regulated public.
    Commenters generally supported the concept of recording of 
examinations, and a number of commenters provided information on the 
type of records of equipment examination that were maintained at their 
mines. The record required by this paragraph may be entered or recorded 
by the qualified person who performed the examination, or by a 
responsible mine official, such as a foreman or superintendent.
    Paragraph (g) requires the mine operator to develop and implement 
written standard operating procedures for weekly testing and evaluation 
of undiluted exhaust emissions from diesel-powered equipment used where 
permissible electrical equipment is required, and from heavy-duty 
diesel-powered equipment as defined in Sec. 75.1908(a), in use 
underground. The paragraph also requires that specific aspects of the 
testing and evaluation process be addressed in the procedures. The 
final rule differs from the proposal in that the proposal would have 
required emission testing of all diesel-powered equipment underground, 
while the final rule narrows the requirement for such testing to 
permissible and heavy-duty nonpermissible equipment. The final rule 
also differs slightly from the proposal in the type of training 
required for the person who tests and evaluates the exhaust emissions.
    The proposed emission testing requirements elicited the most 
controversy among commenters of all of the requirements in this 
section. Some commenters acknowledged that emission testing could be 
useful in monitoring the general operating condition of a diesel engine 
in identifying diesel equipment that needs maintenance. These 
commenters nonetheless expressed serious concern that a standardized 
in-mine test for undiluted exhaust emissions had not yet been devised, 
and until such a test was developed there would be no consistency in 
test results. These commenters recommended that emission test 
requirements not be included in the final rule. In response to these 
comments, the final rule limits required undiluted exhaust emission 
testing to permissible equipment and to heavy-duty nonpermissible 
equipment, as defined under Sec. 75.1908(a). In-mine tests for diesel 
exhaust emissions have in fact been developed for these types of 
equipment. Permissible equipment and heavy-duty nonpermissible 
equipment are also typically the types of equipment that operate under 
load for extended periods of time, and consequently generate high 
levels of emissions relative to other types of equipment. Regular 
testing of the exhaust emissions of this equipment will help to ensure 
that this equipment is properly maintained.
    A number of commenters supplied extensive information on emissions 
tests that had been developed and were being conducted at their mine, 
stating that such tests provided a valuable indication of engines that 
were in need of maintenance. Some commenters who supported the 
requirement for emissions testing in the proposed rule nonetheless 
recommended different testing intervals, ranging from two times per 
shift to once a month. One commenter stated that an emissions test 
frequency of one time per month was appropriate for light-duty 
equipment, while another commenter recommended that emissions be tested 
each week by a person qualified under Sec. 75.1915, and during each 
shift by the equipment operator. The final rule adopts the proposed 
requirement for weekly exhaust emissions testing, consistent with the 
weekly examinations and testing requirement of paragraph (f). A weekly 
testing interval is of sufficient frequency to ensure that 
deteriorating engines are identified and serviced before they create a 
potential health hazard for miners in the area.
    A number of commenters questioned where the exhaust gas should be 
sampled, some stating that they sampled diluted exhaust gas either in 
the equipment operator's compartment or at a significant distance from 
the tailpipe, such as 2 or 3 feet, and in one case 10 feet away. 
Several commenters stated that emissions test should be taken no more 
than 3 inches from the exhaust pipe if a particulate probe is not 
provided, because greater distances will not provide meaningful 
results. One commenter found that testing 2 feet away from the exhaust 
was very unreliable, and that the test results would depend on which 
way the machine was facing. Another commenter believed that test 
procedures used by some mine operators were intended to circumvent the 
goal of testing, which is to gauge engine performance and identify 
equipment that needs maintenance. Other commenters stated that while 
samples taken in the operator's compartment or away from the tailpipe 
can provide valuable information, inconsistent dilution prevents such 
samples from giving the most accurate indication of engine condition. 
One commenter's experience has shown that samples taken directly from 
the exhaust tailpipe provide a more accurate analysis of engine 
performance, and that samples drawn further away are influenced too 
much by the variables of mine ventilation. MSHA agrees with the 
commenters who are concerned about these variables, not least among 
them mine ventilation, that can dilute and distort emission samples 
that are taken any distance away from the machine tailpipe. A 
significantly diluted sample may fail to indicate declining engine 
performance and may not trigger the necessary corrective maintenance, 
thereby exposing miners to unhealthy levels of gaseous emissions. In 
response to these concerns, MSHA has concluded that adopting the 
requirement in the proposal for sampling of the undiluted exhaust 
emissions is the best way to ensure that the measurements will provide 
an accurate indication of deteriorating engine performance. The final 
rule specifically requires the testing of undiluted exhaust emissions, 
which means that emission samples required must be taken directly from 
the tailpipe, not at any distance away.
    Paragraph (g) specifies that the person performing the weekly 
testing and evaluation of exhaust emissions be trained to perform the 
task. The person is not required to be qualified under Sec. 75.1915, 
but does have to be adequately trained. This is a slight modification 
from the proposed rule, which would have required the person conducting 
emissions tests to demonstrate to a person qualified under Sec. 75.1915 
the capability to perform the tests. MSHA has concluded that the 
requirement in the proposed rule that the training be conducted by a 
qualified person is an unnecessary limitation. Mine operators have the 
responsibility of ensuring that persons who perform such tasks are 
adequately instructed in the activity. An important part of carrying 
out that responsibility is making sure that the persons conducting task 
training have the requisite knowledge and experience. Accordingly, the 
final rule simply requires that persons who test and evaluate emissions 
receive the necessary task training.
    Paragraph (g)(1) requires that the emissions testing procedures 
developed by the mine operator include a method for achieving a 
repeatable loaded engine operating condition for each type of 
equipment, and is identical to what was proposed. Most commenters 
stated that a loaded engine test was not feasible for all types of 
equipment, specifically diesel machines equipped with clutches. Several 
commenters emphasized the difficulty of analyzing

[[Page 55491]]

the exhaust emissions of a loaded engine without exposing miners to the 
danger of sudden equipment movement. Other commenters stated that valid 
samples could not be obtained if the engine were not under load. In 
response to these commenters, and as discussed above, the final rule 
limits the requirement for exhaust testing to permissible equipment and 
heavy-duty nonpermissible equipment. These types of equipment are 
generally not equipped with clutched transmissions, and therefore do 
not present the problems identified by commenters that would exist with 
loaded engine tests for diesel equipment with clutches. As mentioned 
earlier, MSHA has developed loaded engine test procedures for the 
equipment subject to testing under the final rule.
    Paragraph (g)(2) requires that the procedures for weekly testing 
and evaluation of the undiluted exhaust emissions of diesel engines 
specify sampling and analytical methods that include calibration of 
instrumentation capable of accurately detecting carbon monoxide in the 
expected concentrations. Commenters indicated that instruments are 
available and currently being used for accurate emissions testing. 
Several commenters stated that testing should not be limited to carbon 
monoxide, stating that they were currently testing for other gases, 
such as sulfur dioxide and the oxides of nitrogen. Other commenters 
were of the opinion that carbon monoxide concentrations were the best 
indicator of engine performance.
    After consideration of all comments, MSHA has concluded that 
sampling for carbon monoxide alone is sufficient for determining a 
change in engine performance that may reflect a need for maintenance. 
Data indicates that carbon monoxide increases the most among the 
exhaust gases when an engine is poorly maintained, and is the best 
indicator that an engine needs attention. See, Report of the Bureau of 
Mines, U.S. Department of the Interior, ``Relationship of Underground 
Diesel Engine Maintenance to Emissions'' (December 1983). Sampling for 
nitrogen dioxide is required by Sec. 70.1900 of the final rule. This 
will ensure that miners are not exposed to contaminants at levels above 
the applicable limits.
    Paragraph (g)(3) requires that the procedures for emissions testing 
and evaluation include evaluation and interpretation of the emission 
test results. Commenters generally supported this requirement, and 
several commenters provided information on their evaluation and 
interpretation of results. This provision has been adopted unchanged 
from the proposed rule.
    Paragraph (g)(4), like the proposal, requires that the testing 
procedures developed by the operator specify the concentration or 
changes in concentration of carbon monoxide that will indicate a change 
in engine performance. The paragraph also provides that concentrations 
of carbon monoxide shall not exceed 2500 parts per million, which is 
the limit for carbon monoxide established in the test procedures for 
Category B engines in subpart E of part 7 of the final rule. This 
aspect of the proposal received little comment, and has been adopted 
without change in the final rule.
    Paragraph (g)(5) requires that the testing and evaluation 
procedures address the maintenance of records that are necessary to 
track engine performance. Commenters supported this requirement and 
indicated that some mines are already maintaining emissions records. 
The proposed rule would have required that the procedures address 
``maintenance and retention of necessary records''. MSHA has added 
language to this paragraph to eliminate any ambiguity that might have 
been created by the term ``necessary records'', by specifying the 
purpose of the records required under this paragraph. MSHA has also 
eliminated the reference in the proposed rule to the ``retention'' of 
records, and has chosen instead to address retention of records in a 
new paragraph (h) in this section, discussed below.
    Paragraphs (h)(1) and (h)(2) provide that records required by 
paragraphs (f)(2) and (g)(5) of this section must be recorded in a 
secure book that is not susceptible to alteration, or recorded 
electronically in a computer system that is secure and not susceptible 
to alteration. The records must be retained at a surface location for 
at least 1 year and made available for inspection by an authorized 
representative of the Secretary and by miners' representatives.
    The proposed rule did not address the availability of or access to 
records under this section. One commenter recommended that records of 
weekly examination be accessible to miners' representatives. MSHA 
agrees with this comment, and has revised the paragraph to provide 
miners' representatives with access to records. The final rule also 
requires such access for authorized representatives of the Secretary, 
to allow MSHA inspectors to review records to verify that examinations 
and tests required under this section have been conducted.
    The final rule does not specify a particular way of making records, 
only that they are to be recorded in a manner that is not susceptible 
to alteration. A detailed discussion on the issue of recordkeeping and 
electronic records can be found under ``Recordkeeping Requirements'' in 
the General Discussion section of this preamble.
    The proposed rule would have required that the emission testing 
procedures under paragraph (g) include the designation of training of 
the individual who performs the tests. This requirement has not been 
adopted in the final rule. Instead, as discussed earlier, the rule 
imposes a performance-based requirement that emissions testing and 
evaluation under this paragraph be conducted by a person who has been 
trained to perform the task. Mine operators are consequently 
responsible for ensuring that individuals who test and evaluate 
emissions receive the training necessary to ensure their competence. 
The ability of these persons to discharge their responsibilities is of 
much greater concern to MSHA than the training they receive to achieve 
it, and the final rule reflects this emphasis.
    Finally, several commenters recommended that this section include a 
requirement for regular examination of fire suppression systems. 
Examination of fire suppression systems is not addressed here, but 
instead is dealt with in Sec. 75.1911 of the final rule, which provides 
that equipment fire suppression systems be visually inspected at least 
once each week, and be tested and maintained in accordance with the 
manufacturer's recommended inspection and maintenance program.
    Paragraph (i) provides that diesel-powered equipment must be 
maintained in accordance with this part beginning 12 months after the 
date of publication of the final rule. This time is allowed for the 
development of a training and qualification program under Sec. 75.1915 
and for the training of individuals who perform work on diesel-powered 
equipment. MSHA recognizes that the resources available for training in 
particular geographical areas may be limited in some cases, and that 
competent trainers may be in significant demand as mine operators 
prepare to comply with the requirements of the final rule. A one-year 
delayed effective date for the requirements of this section should 
afford the mining community sufficient time to prepare for compliance.

[[Page 55492]]

Section 75.1915  Training And Qualification Of Persons Working On 
Diesel-Powered Equipment
    This section of the final rule requires a training and 
qualification program for persons who perform maintenance, repairs, 
examinations and tests on diesel-powered equipment, as required by 
Sec. 75.1914. These critical tasks must be performed correctly for 
diesel equipment to be maintained in safe condition with acceptable 
levels of emissions. The final rule sets minimum, performance-based 
requirements for training and qualification programs, and requires 
successful completion of such a program for a person to be qualified to 
perform diesel maintenance, repairs, examinations, and tests.
    The final rule differs from the proposed rule in several respects: 
it does not require the training and qualification programs to be 
approved by MSHA; it does not specify an interval for retraining; it 
clarifies that the rule does not require MSHA approval of instructors 
who provide training; and it eliminates the use of the term ``diesel 
mechanic''.
    Paragraph (a) of this section of the final rule provides that in 
order to be qualified to perform maintenance, repairs, examinations, 
and tests on diesel-powered equipment, as required by Sec. 75.1914, a 
person must complete a training and qualification program which meets 
the requirements of the section. A qualified person is required to be 
retrained when necessary to maintain the ability to perform all 
assigned maintenance, repairs, examinations, and tests. The final rule 
does not require, as would have the proposed rule, that MSHA approve 
training and qualification programs developed under this section.
    Although there was virtually universal agreement among commenters 
that some form of training was essential for persons working on diesel 
equipment, commenters disagreed about the need for a formal training 
and qualification program and the necessity of MSHA review and approval 
of such programs. Some commenters were of the opinion that persons 
working on diesel equipment should be formally qualified, and that 
diesel training programs for qualification should meet strict minimum 
standards and be subject to approval by MSHA. One commenter stated that 
if strict training requirements were not included in the standard, the 
necessary training would not be provided.
    Other commenters opposed requiring a formal program with specific 
requirements, advocating as an alternative performance-oriented 
standards that could be adapted to a mine's specific needs. One 
commenter stated that a formal qualification scheme was unnecessary, 
and that diesel maintenance training should be provided on an as-needed 
basis in the same manner as task training under part 48. Another 
commenter maintained that the benefits realized from a formal 
qualification program would not justify the additional administrative 
burdens of such a program. The Office of Management and Budget guidance 
comments directed MSHA to reexamine whether all of the information 
proposed to be submitted to MSHA for approval of training and 
qualification programs had practical utility and imposed the least 
burden on mine operators.
    Numerous other commenters, while supporting the establishment of 
procedures to qualify persons to perform work on diesel equipment, were 
opposed to the proposed requirement that MSHA approve training and 
qualification programs. Many commenters indicated that very good diesel 
equipment maintenance training is already being provided by mine 
operators as well as equipment manufacturers, without MSHA review or 
approval. In contrast, other commenters maintained that training 
programs should meet the approval of all interested parties, including 
MSHA and the representative of miners, to ensure that the training is 
adequate. The Diesel Advisory Committee had unanimously recommended 
that MSHA require persons performing work on approved diesel equipment 
features be trained and tested for competency, and that the training 
and testing be approved by MSHA.
    After careful consideration of all of these views and comments, 
MSHA has concluded that a basic structure for training and 
qualification programs for persons performing certain work on diesel 
equipment is necessary. Properly trained persons are fundamental to 
adequate maintenance of diesel-powered equipment. To meet this 
objective, MSHA believes minimum criteria for the training and 
qualification of these persons are essential. Paragraph (a) therefore 
provides that to be qualified to perform diesel equipment maintenance, 
repairs, examinations, and tests, as required by Sec. 75.1914, a person 
must successfully complete a training and qualification program meeting 
the requirements of the section.
    The proposal that MSHA review and approve training and 
qualification programs is not adopted in the final rule. MSHA's paper 
review of training and qualification programs, as proposed, could 
provide an initial check of the quality of the program. Such a review 
would not, however, ensure that the program is successful in its 
implementation. Rather than expending Agency resources on the review 
and approval of diesel training programs, MSHA will direct those 
resources toward verification of the effectiveness of training and 
qualification programs in their execution. Similarly, mine operators 
and training providers can focus on the development and administration 
of their training and qualification programs rather than on procedures 
to gain MSHA approval. The rulemaking record contains a number of well-
designed diesel training plans already in effect, demonstrating that 
the mining community has the expertise needed to develop and implement 
effective training programs. MSHA will closely monitor the 
effectiveness of the training programs implemented under this section.
    Paragraph (a) also requires retraining when needed. The proposed 
rule would have required qualified persons to undergo retraining every 
12 months. Some commenters to the proposed rule opposed the 
establishment of a specific requirement for annual retraining, stating 
that the mining industry needed performance-oriented standards that 
could be adapted to mine-specific needs for maintenance and training. 
Other commenters stated that an annual retraining requirement was 
necessary to ensure that persons working on diesel-powered equipment 
maintained the necessary knowledge and expertise over time.
    MSHA considers retraining to be an important part of any training 
program. The final rule, however, does not mandate retraining at 
specified intervals. MSHA has concluded that mine operators should 
tailor the frequency of retraining to the conditions and practices at 
each mine, to ensure that all persons who work on diesel-powered 
equipment maintain the requisite level of expertise. Factors that could 
affect the timing of retraining include the frequency with which the 
qualified person works on specific pieces of diesel equipment; newly 
developed techniques for performing the required inspections and tests; 
and any modifications that may have been made to the equipment since 
the last training. Frequent retraining may be necessary at some mines 
to ensure that qualified persons retain sufficient skill and knowledge 
to perform their jobs effectively. At other mines where conditions are 
less changeable, retraining at greater intervals may be appropriate.

[[Page 55493]]

    Paragraph (a) of the final rule also eliminates the term ``diesel 
mechanic'', was used in the proposal to identify those persons 
qualified to perform maintenance and repairs of approved features of 
diesel equipment. Many commenters to the proposed rule objected to the 
use of the term, stating that it would result in the creation of a new 
job title or classification. MSHA did not intend to establish a new job 
classification through the use of the term ``diesel mechanic'', and 
concludes from the comments that its use would result in confusion. The 
term ``diesel mechanic'' has therefore not been adopted in the final 
rule.
    Finally, the phrase ``examinations and tests'' has been included in 
paragraph (a) of the final rule, reflecting that a person qualified 
under this section would be authorized to conduct weekly examinations 
and tests of diesel-powered equipment under Sec. 75.1914(f), in 
addition to maintenance and repairs of such equipment under 
Sec. 75.1914(b).
    Paragraph (b) provides a basic structure for training and 
qualification programs, but is intended at the same time to provide 
mine operators with sufficient latitude in developing their programs. 
MSHA believes that training and qualification programs will be most 
effective if they are tailored to specific mining conditions and 
equipment in use at the mine, as well as to the skill levels and 
experience of the persons being trained.
    A number of commenters reported that they already have training and 
qualification programs in place at their mines, and provided 
descriptions and documentation of these programs. Many of these 
programs utilize training at off-site facilities, such as community 
colleges and technical and trade schools. Commenters also indicated 
that mining equipment manufacturers are typically called upon to 
provide training. These programs generally include classroom training 
modules as well as hands-on in-mine training on specific pieces of 
equipment. Commenters stated that the duration of training programs 
could be from three days to eight weeks. The length of the program was 
generally dependent upon how much diesel-powered equipment was used at 
the mine, as well as on the previous experience and skill level of the 
persons being trained.
    MSHA anticipates that local community colleges and technical 
schools will assist mine operators in developing the training and 
qualification programs required under this section. Commenters 
indicated that this type of assistance is already being provided to 
mine operators in a number of areas of the country.
    Paragraph (b)(1) requires that training courses be presented by a 
competent instructor, in contrast to the proposed rule, which would 
have required that courses for training and retraining be conducted by 
either a qualified diesel mechanic or ``other instructor determined by 
MSHA to be qualified.'' Several commenters objected to this aspect of 
the proposal, based on their belief that the proposal required some 
type of formal approval by MSHA before anyone other than a qualified 
person could conduct diesel training under this section. A number of 
other commenters believed that such approval would only add an 
unnecessary procedural hurdle to providing training. Contrary to the 
understanding of such commenters, MSHA did not intend by the proposal 
to approve training instructors. The language of the final rule has 
been clarified to provide that courses may be presented by a competent 
instructor. A competent instructor under paragraph (b)(1) could be a 
person qualified under Sec. 75.1915, an instructor from a trade school 
or college, or a person experienced in diesel maintenance, such as a 
representative of an equipment or engine manufacturer, or even the 
chief of maintenance at the mine, provided that the instructor has the 
necessary technical expertise.
    Paragraph (b)(2) of the final rule provides that the training and 
qualification program must be sufficient to prepare or update a 
person's ability to perform all assigned tasks with respect to diesel-
powered equipment maintenance, repairs, examinations, and tests. This 
paragraph incorporates the requirements of proposed paragraphs (e)(2) 
and (e)(3), except that it substitutes the term ``person'' for the term 
``diesel mechanic,'' for the reasons stated in the discussion of 
paragraph (a) of this section. Several commenters were opposed to the 
requirement in proposed paragraph (e)(3) that courses in the training 
program address each piece of diesel-powered equipment in use at the 
mine, stating that this could be an unnecessary burden at mines that 
operate a variety of types of diesel-powered equipment. These 
commenters stated that if an individual never worked on certain pieces 
of equipment, requiring that individual to receive training on all 
equipment in use at the mine would be unnecessary.
    MSHA did not intend proposed paragraph (e)(3) to require that each 
qualified person be trained on all types of diesel-powered equipment in 
use in the mine, only those pieces of diesel-powered equipment the 
qualified person actually works on. However, the language of proposed 
paragraph (e)(3) could be interpreted to require that the courses in 
the training program cover all pieces of diesel equipment in use at the 
mine.
    MSHA agrees with the commenters that training should be tailored to 
the duties and responsibilities of the individual qualified person. The 
language in the final rule has therefore been clarified to reflect this 
concept. A qualified person is not required to be trained on a 
particular type of equipment, unless he or she performs work on it. 
However, a person who is untrained on a particular type of equipment is 
not a qualified person with respect to that equipment, and may not 
perform maintenance, repairs, and tests required to be conducted by a 
qualified person. Finally, MSHA anticipates that training will address 
equipment by model and not by individual machine, unless machines at 
the mine with the same model number differ because of field changes or 
other special features. In such cases training would need to take into 
account any significant differences among machines.
    While MSHA's intent is to promote flexibility in the implementation 
of training and qualification programs, the final rule does specify 
minimum topics of instruction for these programs. Paragraphs (b)(3)(i) 
through (b)(3)(vii) of the final rule set forth the specific areas of 
instruction that must be covered by a training and qualification 
program. Commenters were generally in agreement with the areas of 
instruction required under the proposed rule, and the language of the 
final rule is virtually the same as what was proposed''.
    Paragraph (b)(3)(i) requires that training programs address the 
``requirements of subpart T of this part''. Several commenters 
recommended that the phrase ``as applicable'' be added to this 
requirement, to eliminate the need for training to address requirements 
that may not be directly applicable at the specific mine. This 
recommendation is not adopted in the final rule. MSHA believes that a 
person qualified under this section should have, at a minimum, basic 
familiarity with the scope of subpart T and the diesel-powered 
equipment safety standards. However, MSHA does not intend that this 
aspect of the final rule require exhaustive coverage of requirements 
that have no application to the mine in question. The well-designed, 
mine-specific training program contemplated by this section will focus 
on the requirements that are the most relevant. For example, if a mine 
does not store diesel fuel underground, qualified persons working

[[Page 55494]]

at that mine would not be expected to have extensive knowledge of the 
requirements of the standards governing fuel storage. Qualified persons 
should nonetheless be aware that subpart T contains provisions that 
address underground fuel storage.
    Paragraph (b)(3)(ii) is virtually identical to proposed paragraph 
(e)(4)(ii), and requires that the training program address the use of 
power package or machine checklists to conduct tests to ensure that 
diesel equipment is in approved and safe condition, with acceptable 
emission levels. Some commenters reported that maintenance of the 
permissibility features of approved equipment was often neglected, and 
emphasized the importance of using only trained personnel to evaluate 
these features. This requirement is intended to ensure that training 
addresses the evaluation of the equipment's permissibility features. 
Several commenters also questioned the meaning of the term ``safe 
operating condition''. The term has been changed to ``safe condition'' 
to conform to the terminology in Sec. 75.1914. MSHA intends that ``safe 
condition'' used in this paragraph means that the equipment has been 
maintained in compliance with subpart T of this part and does not 
present a hazard to miners. Finally, the language of this paragraph has 
been slightly revised to delete the term ``appropriate'' from the 
phrase ``to conduct appropriate tests'', because it is unnecessary and 
redundant.
    Paragraph (b)(3)(iii) of this section is identical to proposed 
paragraph (e)(4)(iii), and requires that the training program cover the 
proper maintenance of approved features and the correct use of 
appropriate maintenance manuals, including machine adjustments, 
service, and assembly. Paragraph (b)(3)(iii) is different from 
paragraph (b)(3)(ii) in that it addresses proper maintenance of 
equipment, while paragraph (b)(3)(ii) addresses tests to ensure 
permissibility.
    Paragraph (b)(3)(iv) of the final rule requires that training under 
this section address tests and maintenance of fire suppression system 
on diesel-powered equipment. The final rule uses the phrase ``fire 
suppression system'' rather than ``fire protection system,'' which was 
used in the proposed rule, to conform the language of the final rule to 
terminology that is more commonly in use. The purpose of this 
requirement is to ensure that a qualified person has sufficient 
familiarity with the elements of fire suppression systems used on 
diesel equipment.
    Paragraph (b)(3)(v) of this section requires that fire and ignition 
sources and their control and elimination, including cleaning the 
equipment, be addressed by the training program. The phrase ``including 
cleaning of the equipment'' has been added in response to comments 
emphasizing the importance of frequent cleaning of equipment to prevent 
the accumulation of combustible materials such as oil, grease and float 
coal dust and thereby reduce the risk of fire. This requirement is 
consistent with and is intended to reinforce compliance with 
Sec. 75.400, which has been revised in this final rule to specifically 
prohibit accumulations of combustible material on diesel-powered 
equipment.
    Paragraph (b)(3)(vi) of this section requires that the training 
program address safe fueling procedures and maintenance of the 
equipment's fuel system. The importance of proper refueling procedures 
is illustrated by the analysis of the Canadian fire accident data in 
the discussion of Sec. 75.1908. These data show that the failure to 
follow proper refueling procedures resulted in several fires.
    Paragraph (b)(3)(vii), like the proposal, requires that the 
training program address maintenance and testing of the engine's intake 
air system. A number of commenters reported that failure to replace 
dirty intake air filters was the most frequent cause of excessive 
levels of smoke and carbon monoxide from otherwise properly adjusted 
engines.
    Proposed paragraph (e)(4)(viii) would have required the training 
course to address tests and maintenance of the engine shutdown device. 
Because engine shutdown devices are in fact components of permissible 
equipment, training covering these devices will already be required by 
paragraphs (b)(3) (ii) and (iii) of this section, discussed above. The 
language of proposed paragraph (e)(4)(viii) has therefore not been 
included in the final rule.
    Proposed paragraph (e)(4)(ix) would have given the district manager 
the authority to require the training program to cover additional 
subjects necessary to address specific health and safety needs. This 
provision has not been adopted in the final rule, which is designed to 
be more performance-oriented. As discussed above, the requirements of 
this section are intended to result in the development of training 
programs that are tailored to the specific needs of each mine, 
including the equipment being used and the skill levels of the persons 
receiving the training. Failure to address mine-specific health and 
safety needs in the training program may result in MSHA determining 
that a mine operator is not in compliance with Sec. 75.1915. 
Additionally, the proposed rule would have required MSHA approval of 
training programs and would have provided a framework for the exercise 
of district manager authority under proposed paragraph (e)(4)(ix). As 
discussed above, the final rule does not require MSHA approval of 
training programs. For these reasons, this proposed provision has not 
been adopted in the final rule.
    Paragraph (b)(4) requires the training and qualification program to 
include an examination that requires demonstration of the ability to 
perform all assigned tasks with respect to diesel equipment 
maintenance, repairs, examinations, and tests. There is no specific 
requirement that the examination be in writing, although an examination 
that effectively assesses competence will most likely include a written 
test as well as a practical portion that allows a hands-on evaluation 
of a person's abilities. Under the proposed rule, a minimum score of 80 
percent would have been required on any written portion of a 
qualification examination. Although some commenters supported the 
concept, MSHA has concluded that mandating a minimum score is 
unnecessary when a written portion is not a required part of the 
examination. Further, such a specific requirement is at odds with the 
performance-oriented approach of this paragraph. The requirement for a 
minimum score has therefore been omitted from the final rule.
    Paragraph (b)(5) requires that the training and qualification 
program be in writing, and contain a description of the course content, 
materials, and teaching methods to be used for initial training and 
retraining. The language of this paragraph is substantially the same as 
proposed paragraph (d)(1), except that the word ``approved'' has been 
omitted. As discussed above, the program will not be subject to MSHA 
approval under the final rule.
    The requirements of proposed paragraphs (d)(2) and (d)(3) have not 
been adopted in the final rule. Specifically, proposed paragraph (d)(2) 
would have required that the training and qualification program include 
a copy of the examination, to allow MSHA to review the examination as 
part of the approval process. Because the final rule does not require 
MSHA approval, and also because a written examination is not required, 
a copy of the examination does not need to be included as part of the 
program.
    Proposed paragraph (d)(3) would have required that the program 
include a description of the evaluation program to be used for 
retraining to assess the knowledge, skills, and ability of the

[[Page 55495]]

qualified person. This requirement has not been included in the final 
rule, consistent with MSHA's intention to measure the effectiveness of 
training and qualification programs by how well diesel-powered 
equipment is being maintained at the mine, rather than by the adequacy 
of a written program. Consequently, the final rule does not require a 
retraining evaluation program, but MSHA expects that mine operators 
will closely monitor the maintenance of diesel equipment at their 
mines, and will ensure that qualified persons receive the necessary 
retraining.
    Paragraph (c) of this section requires the mine operator to 
maintain a copy of the training and qualification program required by 
this section and a record of the names of all persons qualified under 
the program. Paragraph (c)(1) requires that the record of the names of 
qualified persons be made in a manner that is not susceptible to 
alteration or recorded electronically in a computer system that is 
secure and not susceptible to alteration. Under paragraph (c)(2), the 
training and qualification program and the record of qualified persons 
must be kept at a surface location of the mine and made available for 
inspection by an authorized representative of the Secretary and by 
miners' representatives. Paragraph (c) incorporates, with certain 
revisions, the requirements originally proposed in Secs. 75.1916 (i) 
and (j). Proposed Secs. 75.1916 (i) and (j) would have required a list 
of current instructors also to be included in the training and 
qualification program and, in addition to the names of all qualified 
persons, the dates of qualification and the date of the last 
retraining. MSHA has removed these additional recordkeeping 
requirements from the final rule, consistent with the Agency's 
intention to gauge the adequacy of training and retraining by how 
effectively diesel-powered equipment at the mine is maintained. The 
final rule does not specify a particular method for maintaining the 
record of qualified persons, only that it is not susceptible to 
alteration. A detailed discussion of recordkeeping and electronic 
records can be found under the heading ``Recordkeeping Requirements'' 
in the General Discussion section of this preamble.
    Finally, the proposed rule specified procedures in Sec. 75.1916 for 
MSHA's administration of training and qualification programs. Among 
other things, the proposed rule set forth a process for MSHA review and 
approval of the training and qualification program required under 
Sec. 75.1915, and established procedures for the revocation of 
individual qualifications. Because MSHA will not be formally reviewing 
and approving training and qualification programs, procedural 
requirements for review and approval are unnecessary. Consequently, the 
provisions proposed in Sec. 75.1916 have not been retained in the final 
rule, with the exception of the requirements of proposed 
Secs. 75.1916(i) and (j), as discussed above.
Section 75.1916 Operation Of Diesel-Powered Equipment
    Section 75.1916 addresses speed limits and other traffic 
restriction on roadways in underground coal mines where diesel-powered 
equipment is operated. This section also prohibits unnecessary idling 
of diesel-powered equipment, as well as the operation of unattended 
diesel-powered equipment.
    The Diesel Advisory Committee advocated MSHA regulation of 
operating conditions of diesel-powered equipment, recommending proposal 
of a rule that addressed speed limits, road conditions, and operator 
control of vehicles. This section is intended to ensure that diesel-
powered equipment underground is operated in a safe manner, and 
requires that operating speeds of diesel-powered equipment be 
consistent with conditions in the mine, and that operators of diesel-
powered equipment maintain full control of the equipment when it is in 
motion. Standardized traffic rules, including speed, signals, and 
warning signs, are required to be established at each mine and 
followed.
    The final rule recognizes that the safe operating speed for a 
particular piece of diesel-powered equipment depends greatly on the 
specific mining conditions and the type of equipment being operated, 
and as a result the final rule does not establish a universal speed 
limit for diesel-powered equipment operated in underground coal mines. 
Finally, idling of mobile diesel-powered equipment is prohibited, 
except as required in normal mining operations. Operation of unattended 
diesel-powered equipment is also prohibited under this section.
    Several commenters recommended elimination of the requirements of 
this section, stating that the proposed standards were too vague and 
could result in inconsistent enforcement. Some of these commenters 
suggested reducing the proposed requirements of this section to a 
single requirement that the mine operator establish traffic rules, 
appropriate for the specific mine conditions at each mine, that address 
speed and operator control of equipment. A number of commenters also 
pointed out that existing Sec. 75.1403 gives MSHA the authority to 
regulate hazards arising from the transportation of men and materials 
at underground coal mines. These commenters believed that 
transportation hazards were already adequately covered under 
Sec. 75.1403, and that additional regulation was therefore unnecessary.
    The existing authority to issue safeguards under Sec. 75.1403 does 
not make the requirements of this section unnecessary. Section 75.1403 
authorizes an MSHA inspector to issue a ``safeguard notice'' when the 
inspector determines that a transportation hazard exists at a mine and 
the hazard is not already addressed by a mandatory standard. The 
``safeguard notice'', issued by an MSHA inspector to the mine operator, 
identifies the nature of the hazard and establishes requirements based 
on the actual conditions or practices that constitute a transportation 
hazard at the particular mine. After the mine operator is given a 
reasonable time to come into compliance with the requirements set forth 
in the safeguard notice, the safeguard has the force and effect of a 
mandatory standard at the mine and can be enforced as such. Sections 
75.1403-1 through 75.1403-11 contain criteria to guide inspectors in 
issuing safeguards, covering a wide range of potential transportation 
hazards, such as clearance distances on belt conveyors and track 
haulage roads, brakes on hoists and elevators, and safety gates for 
entrances to shafts and slopes.
    Safeguards are not a substitute for the mandatory requirements in 
Sec. 75.1916. Although some of the topics covered in this section, such 
as speed limits and roadway conditions, are included as safeguard 
criteria in Secs. 75.1403-1 through 75.1403-11, the criteria are not 
enforceable unless and until they have been incorporated in a safeguard 
notice, after an MSHA inspector has determined that a hazard exists. In 
contrast, the requirements of this section of the final rule apply at 
all underground coal mines where diesel-powered equipment is used. In 
addition, safeguard criteria are intended to be tailored to the unique 
conditions and practices at an individual mine, while the requirements 
in this section are general in nature, although mine operators are 
given the flexibility to set traffic rules appropriate for the 
conditions at their mines. The final rule therefore does not reflect 
the opinion of some commenters that the requirements under this section 
are unnecessary.
    The requirements of this section specifically govern the manner and 
conditions under which diesel-powered

[[Page 55496]]

equipment operates in underground coal mines, and recognize that 
diesel-powered equipment tends to be much larger and more powerful, and 
to have the ability to travel at much greater speeds than electric-
powered equipment. Some types of diesel-powered equipment used in 
underground coal mines, such as pickup trucks, are designed for use on 
highways, and can travel at speeds in excess of 60 miles per hour 
(mph). In comparison, a typical piece of mobile rubber-tired battery-
powered equipment will have a top speed of less than 10 mph. The 
potential traffic hazards are therefore significantly greater in the 
operation of diesel-powered equipment, and there is a resulting need 
for the minimum requirements set by the final rule at mines where 
diesel-powered equipment is operated.
    Paragraph (a) of this section adopts the requirements of the 
proposal and provides that operating speeds of diesel-powered equipment 
must be consistent with the type of equipment being operated, the 
conditions of roadways, grades, clearances, visibility, and other 
traffic. Under this paragraph diesel-powered equipment must be operated 
at all times at safe speeds, which in many cases will be slower than 
the maximum speed limit set in the mine-wide traffic rules established 
under paragraph (c).
    Some commenters recommended that the rule specify a maximum speed 
limit, such as 15 mph or 25 mph, that would apply at all underground 
coal mines. These commenters stated that a standardized speed limit 
would promote compliance because the rules would be the same at all 
mines everywhere. A few of these commenters recommended that equipment 
be fitted with gear reduction ratios that would make it mechanically 
impossible for equipment to be operated at speeds above the limit. 
Other commenters opposed the establishment of a universal speed limit 
for all mines, stating that safe speeds were highly dependent on 
variable mining conditions, and that a speed that is prudent under one 
set of circumstances could be quite unsafe, even reckless, under 
another.
    The requirements of this paragraph recognize that certain mine 
conditions and equipment characteristics must be taken into account in 
determining the speed at which equipment can be safely operated. Mine 
conditions have been a contributing factor in many traffic accidents. 
Adverse conditions that can negatively impact equipment safety include 
steep grades and slippery mine surfaces, which decrease the 
effectiveness of equipment brakes. Particularly large diesel-powered 
machines, which can take up nearly an entire mine entry, can present 
significant limitations in visibility for the equipment operator, whose 
line of vision is below the machine frame. Consequently, the equipment 
operator has several large blind spots where other pieces of equipment 
and mine personnel cannot be seen. Large haulage units operating in the 
same area as small pieces of diesel-powered equipment can create 
particularly dangerous traffic patterns. The proposed rule would have 
required roadways to be kept as free as practicable from bottom 
irregularities or other conditions that could affect control of the 
equipment. A number of commenters recommended elimination of this 
paragraph, noting that the proposed rule would require standardized 
traffic rules and could be used to address concerns about roadway 
conditions. Other commenters supported this proposed requirement, 
citing the dangers that can result from poorly maintained roads.
    Although MSHA agrees that keeping mine roads free from bottom 
irregularities, debris, and wet or muddy conditions is important to 
safe operation of diesel-powered equipment, the requirements of 
paragraphs (a), (b), and (c) of this section of the final rule are 
sufficient to address concerns about adverse road conditions. The 
requirements of proposed paragraph (a), which would have required 
roadway maintenance, have therefore not been adopted in the final rule.
    Under the requirements of the final rule, vehicle speed must take 
into account roadway conditions and other factors that affect safe 
equipment operation. Equipment operators are required to maintain full 
control of their equipment, and traffic rules must be established and 
followed at each mine where diesel-powered equipment is operated.
    Paragraph (b) also adopts the requirements of the proposal and 
provides that equipment operators must maintain control of mobile 
diesel-powered equipment while it is in motion. Commenters generally 
supported this requirement, which recognizes that there may be cases 
where the roadway conditions, posted operating speed, and traffic rules 
are adequate but other factors interfere with the equipment operator's 
ability to exercise full control over the equipment. For example, the 
rule would prohibit the operator from carrying tools or supplies in the 
operator's compartment that interfere with the operator's ability to 
control the equipment. Additionally, equipment controls must be free of 
any debris which could obstruct safe operation. Operator inattention 
could also constitute a violation of this requirement if the 
inattention causes unsafe operation of the equipment.
    Paragraph (c) requires that standardized traffic rules, including 
speed limits, signals, and warning signs, be established and followed 
at each mine. Under this provision, the mine operator must develop 
mine-wide traffic rules to address hazards arising from the operation 
of diesel-powered equipment, and ensure that mine employees are aware 
of the rules and comply with them. This is consistent with the 
suggestions of several commenters, who supported simplifying the 
proposed rule requirements by a single provision that mine operators 
establish safe operating rules appropriate for mine conditions. The 
requirements in the final rule are similar to those of the proposal, 
except that the final rule provides that traffic rules must be 
``followed'', and does not adopt the proposed requirement that the 
rules be ``posted.'' Mine operators have the responsibility to take 
whatever steps are necessary to ensure that their employees are 
familiar with the mine's traffic rules and follow them. Although 
posting of traffic rules can serve as a means for mine operators to 
facilitate compliance, it is not specifically required under the final 
rule.
    Commenters who advocated a standardized maximum speed limit at all 
underground coal mines, in response to proposed paragraph (b), renewed 
this recommendation in their comments to this paragraph. For the 
reasons discussed above, the final rule does not impose a universal 
speed limit. Some commenters suggested that simply requiring the 
establishment of a mine-wide speed limit would eliminate the need for 
other traffic rules. MSHA disagrees that restrictions on speed alone 
will eliminate potential traffic hazards. The traffic rules required 
under this paragraph are intended to address other factors that affect 
safe operation of diesel-powered equipment, such as changes in mining 
conditions.
    Some commenters recommended that MSHA provide criteria for mine 
operators to use in establishing mine traffic rules, and that operators 
develop traffic plans, consistent with these criteria, that are 
reviewed and approved by MSHA. The final rule does not adopt this 
recommendation. Although MSHA's review of a mine's traffic rules could 
provide a preliminary check on the adequacy of the rules, such a review 
will not ensure that they have been effectively implemented. The final 
rule reflects MSHA's conclusion that both mine operator and Agency 
resources are

[[Page 55497]]

better spent ensuring that traffic rules are being followed. However, 
if an MSHA inspector determines that an operator's traffic rules fail 
to adequately address the mine's traffic hazards, MSHA will require 
revision of the traffic rules.
    This paragraph also requires that the traffic rules be followed. 
The language in the proposed rule did not specifically require that the 
rules be ``followed,'' although MSHA believes that most commenters 
understood that the rules must be obeyed. To eliminate any possible 
ambiguity or misunderstanding, the rule has been clarified to 
specifically require that the rules be complied with.
    One commenter recommended that mine operators be required to 
investigate and file reports of mine traffic accidents in specific 
circumstances, such as where an injury occurs or where a certain amount 
of damage is sustained. MSHA regulations at part 50 already require 
mine operators to investigate and report certain accidents to MSHA, as 
well as to report to MSHA all occupational injuries and illnesses. MSHA 
has concluded that there is no compelling reason why traffic accidents 
and injuries should be treated differently from other types of mining 
accidents and injuries. The final rule therefore does not adopt this 
comment.
    Paragraph (d) prohibits idling of mobile diesel-powered equipment, 
except as required in normal mining operations. This prohibition has 
been added to the final rule in response to the concerns of some 
commenters, who observed that engines are excessively idled most 
frequently in areas where it is impractical to increase air quantities. 
This results in high levels of exhaust contaminants in these areas of 
the mine, and increases the risks of miner overexposure. The final rule 
addresses this problem by prohibiting unnecessary engine idling. The 
intent of this provision is that equipment parked at any location, 
including the loading point, will be shut down if it is not being used 
to do work.
    Paragraph (e) has been added to the final rule and prohibits the 
operation of unattended diesel-powered equipment. The proposal would 
have prohibited portable limited class equipment from being operated 
unattended. This prohibition is consistent with the decision not to 
adopt the proposed requirements for stationary unattended equipment 
into the final rule, and is explained in detail in the preamble 
discussion of stationary unattended equipment.
Amendment of Certain Part 75 Standards
    MSHA's part 75 sets forth mandatory safety standards for each 
underground coal mine. The final rule amends existing Secs. 75.342, 
75.400, 75.1710 and 75.1710-1 to extend their application to diesel-
powered equipment, requiring the installation of methane monitors on 
certain types of diesel-powered equipment, prohibiting accumulation of 
combustible materials on diesel-powered equipment in active workings of 
underground coal mines, and requiring diesel-powered face equipment and 
shuttle cars to be equipped with substantially constructed cabs or 
canopies. Although these existing standards specifically apply to 
electric equipment, the hazards that these standards are designed to 
address are independent of the power source of the equipment.
    The requirements of these four mandatory safety standards have 
applied to electric-powered equipment for a number of years, and have 
been extremely effective in protecting miners from the hazards of 
fires, explosions, and roof falls. The Diesel Advisory Committee 
recommended that MSHA review its existing standards to determine 
whether any existing safety requirements should be made applicable to 
diesel-powered equipment.
    In the preamble to the proposed rule, MSHA solicited comments on 
extending the applicability of certain listed standards to diesel-
powered equipment. The standards listed in the proposal included 
Sec. 75.313 (now Sec. 75.342, methane monitors); Sec. 75.400 
(accumulation of combustible materials); Sec. 75.400-2 (cleanup 
programs); Secs. 75.523, 75.523-1, and 75.523-2 (emergency 
deenergization of self-propelled equipment); Sec. 75.1107-1 (fire 
suppression devices); and Secs. 75.1710 and 75.1710-1 (cabs and 
canopies on face equipment). MSHA also solicited comments on whether 
any other part 75 standards that were not listed should be made 
applicable to diesel-powered equipment.
    Commenters expressed general support for extending requirements for 
methane monitors, brakes, and cabs and canopies to diesel-powered 
equipment. Some commenters expressed the view that all equipment safety 
features on diesel-powered equipment should be addressed under part 75. 
One commenter suggested that all requirements in part 75, particularly 
Secs. 75.500 through 75.524 (applicable to battery- and electric-
powered equipment), be applied to diesel-powered equipment. Other 
commenters stated that all necessary equipment safety features should 
be required as part of the equipment approval process, rather than as 
standards under part 75.
    The final rule retains MSHA's longstanding approach of including in 
part 75 general equipment safety requirements such as methane monitors, 
prohibitions against accumulation of combustible materials, and cabs 
and canopies. The approach of requiring general safety features in part 
75 has been effective in protecting miners in underground coal mines 
where electric-powered equipment is in use. As discussed below, the 
safety hazards addressed by the standards amended in the final rule are 
the same regardless of the equipment's power source.
    By including these equipment safety requirements in part 75, mine 
operators will have the flexibility to improve safety by making machine 
modifications based on specific conditions at each mine. For example, 
the selection of an appropriate cab or canopy for a machine is 
dependent on mine height and entry width.
Section 75.342 Methane Monitors.
    Methane monitors automatically shut down permissible electric 
mining equipment used to extract or load coal when methane 
concentrations around the equipment reach 2.0 percent. Permissible 
diesel equipment can create the same explosion hazard as permissible 
electric equipment if operated in the presence of high concentrations 
of methane. Also, under certain conditions, a diesel engine can ingest 
methane from the mine atmosphere, resulting in uncontrolled 
acceleration of the diesel engine during start up or operation, and 
produce an ignition of methane in the area.
    Methane monitors are recognized as a critical link in the safety 
protections designed to prevent mine explosions. These monitors are 
normally mounted on equipment that operates in the face area, providing 
the first warning that methane gas is accumulating in potentially 
dangerous quantities.
    The final rule requires methane monitors on all diesel-powered face 
cutting machines, continuous miners, longwall face equipment, loading 
machines, and other diesel-powered equipment used to extract or load 
coal in the working place. By applying the methane monitor requirements 
of existing Sec. 75.342 to diesel-powered equipment, miners working 
around such equipment will be protected from fire and explosion hazards 
to the same degree as miners working in areas where similar electric-
powered equipment is in use.

[[Page 55498]]

Section 75.400 Accumulation of Combustible Materials
    The final rule requires that coal dust, loose coal, and other 
combustible materials be cleaned up and not permitted to accumulate in 
active workings or on electric equipment therein. The hazards of a mine 
fire or explosion in an underground coal mine are similar for diesel-
powered and electric-powered equipment. Coal dust can produce a ready 
fuel source when combined with the lubricating and hydraulic oils used 
in diesel-powered equipment and can start a fire if it comes into 
contact with ignition sources on the equipment. As discussed elsewhere, 
diesel-powered equipment that is not equipped with surface temperature 
controls, such as outby equipment, may have engine and exhaust surfaces 
above the ignition temperature of coal dust. Accumulations of coal dust 
can also contribute to the propagation and severity of mine fires and 
explosions. Because diesel equipment uses large quantities of diesel 
fuel and hydraulic fluid, once a fire starts it can quickly spread due 
to the close availability of these fuel sources on a diesel machine. A 
large fire can then ensue and spread in the mine. By adding the term 
``diesel-powered'' to Sec. 75.400, MSHA intends that the longstanding 
prohibition against the accumulation of combustible materials will now 
be explicitly applied to diesel-powered equipment.
Sections 75.1710 and 75.1710-1--Cabs and Canopies.
    The final rule amends Sec. 75.1710 to require diesel-powered face 
equipment and shuttle cars to be equipped with substantially 
constructed cabs or canopies to protect miners operating such equipment 
from roof falls and rib and face rolls. The final rule also applies the 
installation requirements for cabs and canopies in Sec. 75.1710-1 to 
diesel-powered equipment.
    Cabs and canopies provide very effective protection to equipment 
operators from the hazards of roof and rib falls and in collisions with 
the mine roof and ribs. Since 1972, approximately 250 miner fatalities 
have been prevented by cabs and canopies installed on electric 
equipment. Some mine operators have recognized the clear safety 
benefits of cabs and canopies and have installed these devices on the 
diesel-powered self-propelled face equipment in their mines. By 
specifically extending the existing requirements in these sections to 
diesel-powered self-propelled face equipment, including shuttle cars, 
the operators of all such equipment will be afforded the same 
protection that is currently provided for operators of electric 
equipment.
    Several standards identified in the proposal as possible subjects 
for revision have not been amended in this final rule. Section 75.400-
2, which requires the establishment of a cleanup program for the 
removal of accumulations prohibited under Sec. 75.400, has not been 
specifically amended to include the term ``diesel-powered equipment.'' 
Existing Sec. 75.400-2 does not make reference to a particular type of 
equipment, either diesel- or electric-powered. The standard simply 
requires that a program be established for the cleanup and removal of 
combustible materials. Therefore, Sec. 75.400-2 already applies to 
diesel-powered equipment and amending the standard is unnecessary.
    MSHA also solicited comments in the proposed rule on whether the 
requirements of Secs. 75.523, 75.523-1 and 75.523-2 should be applied 
to diesel-powered equipment. These standards protect equipment 
operators from pinning and crushing injuries by requiring self-
propelled electric face equipment to be equipped with panic bars, which 
quickly deenergize the tramming motors in the event of an emergency. 
The existing standards do not require panic bars if the equipment is 
provided with a substantially constructed cab or canopy in accordance 
with Sec. 75.1710-1, or if other devices approved by MSHA are installed 
to quickly deenergize the tramming motor in the event of an emergency.
    Because Secs. 75.523, 75.523-1, and 75.523-2 make specific 
reference to the interrelationship among electric motors, electrical 
control components, cabs, emergency parking brakes, and panic bars, 
these standards cannot be readily adapted to diesel-powered equipment. 
An MSHA study of diesel-powered face equipment accidents occurring from 
1984 to 1995 found that this type of equipment is manufactured with a 
substantially constructed operator's compartment which provides the 
same protection as a cab. The study also found no pinning or crushing 
accidents of the type that would have been prevented by a panic bar on 
diesel equipment. Since this type of diesel equipment will be evaluated 
under part 36, the approval process can ensure that the protection 
features provided on diesel equipment will provide at least the same 
protection as that provided by a panic bar on electrical equipment. The 
final rule, therefore, does not amend Sec. 75.523 to require panic bars 
or the equivalent on diesel-powered equipment.
    The proposed rule also solicited comment on the applicability of 
existing Sec. 75.1107-1, which requires fire suppression devices on 
certain attended and unattended underground electric equipment, to 
diesel-powered equipment. The fire hazards presented by diesel-powered 
equipment are different from those on electric-powered equipment, due 
to the close proximity of large quantities of hydraulic oils and fuels 
to the heated diesel engine exhaust. Because effective fire suppression 
systems are essential for the safe operation of diesel-powered 
equipment, specific requirements for fire suppression systems on 
diesel-powered equipment are addressed in the final rule at 
Sec. 75.1911.
Derivation Table
    The following table lists final standard section numbers and 
corresponding section numbers of existing standards from which they are 
derived.

------------------------------------------------------------------------
               New sections                       Existing sections     
------------------------------------------------------------------------
Part 7--Subpart E.........................  New, Parts 7, 32, 36        
7.81......................................  New                         
7.82......................................  New, 36.2, 7.2              
7.83......................................  New, 36.6, 7.3              
7.84......................................  New, 32.4(f), 36.26(b),     
                                             36.44, 75.322              
7.85 through 7.87.........................  New                         
7.88......................................  New, 75.322                 
7.89......................................  New                         
7.90......................................  New, 36.11                  
7.91 and 7.92.............................  New                         
Part 7--Subpart F.........................  New, Parts 7, 18, 36        
7.95......................................  New                         
7.96......................................  New, 36.2, 7.2              
7.97......................................  New, 36.6, 7.3              
7.98......................................  New, Part 36--Subpart B     
7.99......................................  New                         
7.100 and 7.101...........................  New, 36.46                  
7.102 and 7.103...........................  New, 36.47                  
7.104.....................................  New, 36.46                  
7.105.....................................  New, 7.6, 36.11             
7.106.....................................  New, 7.8(b)                 
7.107.....................................  New, 7.52                   
7.108 and 7.109...........................  New                         
Part 36...................................  Partly new, Part 31         
36.1......................................  Partly new                  
36.2(e)...................................  Partly new                  
36.2(f)...................................  Partly new, 36.2(h)         
36.6 (b)(2) through (b)(4)................  Partly new                  
36.9(a)...................................  Partly new                  
36.20(b)..................................  Partly new                  
36.20(c)..................................  New                         
36.21.....................................  Partly new                  
36.43(a)..................................  Partly new                  
36.48(b)..................................  Partly new                  
70.1900(a)................................  New, 75.100, 75.362         
70.1900 (a)(1) through (b)(3).............  New                         
70.1900(c)................................  New, 75.322, 75.325(j)      

[[Page 55499]]

                                                                        
70.1900(d)................................  New, 75.363                 
70.1900 (d)(1) through (e)................  New                         
75.325 (f) through (h)....................  New, Part 32                
75.325 (i) and (j)........................  New, Part 32, 75.322        
75.325(k).................................  New, Part 32, 75.371        
75.342 (b)(2) and (c).....................  Partly new                  
75.360(b)(7)..............................  Partly new                  
75.371(r).................................  Partly new                  
75.371 (kk) through (oo)..................  New                         
75.371(pp)................................  New, 75.322                 
75.400....................................  Partly new                  
75.1710 and 75.1710-1.....................  Partly new                  
Part 75--Subpart T........................  New, Part 32                
75.1900...................................  New, 75.301                 
75.1901(a)................................  New, 36.2(i)                
75.1901(b)................................  New                         
75.1901(c)................................  New, 40 CFR 79              
75.1902...................................  New                         
75.1903(a)(1).............................  New, 75.301, 75.340         
75.1903 (a)(2) and (a)(3).................  New                         
75.1903(a)(4).............................  New, 75.333(e), 75.340      
75.1903 (a)(5) through (a)(7).............  New                         
75.1903(b)(1).............................  New, 75.1100-2(f)           
75.1903 (b)(2) through (d)(6).............  New                         
75.1904...................................  New                         
75.1905...................................  New                         
75.1906 (a) through (f)...................  New                         
75.1906(g)................................  New, 75.1107-3 through      
                                             75.1107-6, 75.1107-8       
                                             through 75.1107-16         
75.1906 (h) and (i).......................  New                         
75.1906(j)................................  New, 75.1000-3              
75.1906 (k) and (l).......................  New                         
75.1907...................................  New                         
75.1908...................................  New                         
75.1909 (a)(1) through (a)(3)(i)..........  New                         
75.1909 (a)(3)(ii)........................  New, 36.27(a)(1)            
75.1909 (a)(3)(iii) through (a)(3)(ix)....  New                         
75.1909 (a)(3)(x).........................  New, 36.27(c)               
75.1909 (a)(3)(xi) through (b)(3).........  New                         
75.1909(b)(4).............................  New, 36.28                  
75.1909(b)(5).............................  New, 36.33(b)               
75.1909 (b)(6) through (b)(8).............  New, 36.29                  
75.1909(c)................................  New, 75.523-3, 75.1404,     
                                             75.1404-1                  
75.1909(c)(1).............................  New, 75.523-3(b)(2)         
75.1909(c)(2).............................  New, 75.523-3(b)(3)         
75.1909(c)(3).............................  New, 75.523-3(b)(4)         
75.1909(c)(4).............................  New, 75.523-3(b)(5)         
75.1909(c)(5).............................  New, 75.523-3(c)            
75.1909(c)(6).............................  New                         
75.1909(d)................................  New, 75.523-3(d)            
75.1909(e)................................  New, 75.523-3(e)            
75.1909(f)................................  New, 36.29                  
75.1909 (g) through (j)...................  New                         
75.1910(a)................................  New, 75.518, 75.518-1       
75.1910 (b) through (e)...................  New                         
75.1910(f)................................  New, 75.513, 75.513-1       
75.1910 (g) and (h).......................  New, 75.515                 
75.1910(i)................................  New, 75.514                 
75.1910(j)................................  New                         
75.1910(k)................................  New, 7.44(a)(1)             
75.1910(l)................................  New, 7.44 (d), (e), and (m) 
75.1910(m)................................  New, 7.44(f)                
75.1910(n)................................  New, 7.44(h)                
75.1910(o)................................  New, 7.44(g)                
75.1911 (a) through (k)...................  New                         
75.1911(l)................................  New, 75.380(f), 75.1107-3   
                                             through 75.1107-16         
75.1912(a)(1).............................  New, 75.1107-13             
75.1912 (a)(2) through (b)................  New                         
75.1912(c)................................  New, 75.1101-23             
75.1912(d)................................  New, 75.1107-4              
75.1912 (e) through (g)...................  New                         
75.1912(h)................................  New, 75.1107-16             
75.1912(i)................................  New                         
75.1912(j)................................  New, 75.1101-23             
75.1913...................................  New                         
75.1914...................................  New                         
75.1915...................................  New                         
75.1916(a)................................  New, 75.380(d), 75.1403     
75.1916 (b) through (e)...................  New                         
------------------------------------------------------------------------

Distribution Table

    The following table lists section numbers of existing standards 
which contain provisions that were used in the development of the 
listed final standards.

------------------------------------------------------------------------
             Existing sections                      New sections        
------------------------------------------------------------------------
7.2.......................................  7.82, 7.96                  
7.3.......................................  7.83, 7.97                  
7.6.......................................  7.105                       
7.8(b)....................................  7.106                       
7.44(a)(1)................................  75.1910(k)                  
7.44 (d) and (e)..........................  75.1910(l)                  
7.44(f)...................................  75.1910(m)                  
7.44(g)...................................  75.1910(o)                  
7.44(h)...................................  75.1910(n)                  
7.44(m)...................................  75.1910(l)                  
7.44(a)(1)................................  75.1910(k)                  
7.52......................................  7.107                       
Part 31...................................  Part 36                     
Part 32...................................  Part 7--Subpart E, 75.325   
                                             (f) through (k), and Part  
                                             75--Subpart T              
32.4(f)...................................  7.84                        
Part 36--Subpart B........................  7.98                        
36.2......................................  7.82, 7.96                  
36.2(h)...................................  36.2(f)                     
36.2(i)...................................  75.1901(a)                  
36.6......................................  7.83, 7.97                  
36.11.....................................  7.90, 7.105                 
36.26(b)..................................  7.84                        
36.27(a)(1)...............................  75.1909(a)(3)(ii)           
36.27(c)..................................  75.1909(a)(3)(x)            
36.28.....................................  75.1909(b)(4)               
36.29.....................................  75.1909 (b)(6) through      
                                             (b)(8) and (f)             
36.33(b)..................................  75.1909(b)(5)               
36.44.....................................  7.84                        
36.46.....................................  7.100, 7.101, 7.104         
36.47.....................................  7.102, 7.103                
75.100....................................  70.1900(a)                  
75.301....................................  75.1900, 75.1903(a)(1)      
75.322....................................  7.84, 7.88, 70.1900(c),     
                                             75.325 (i) and (j),        
                                             75.371(pp)                 
75.325 (g) and (i)........................  75.371(r)                   
75.325(j).................................  70.1900(c)                  
75.333(e).................................  75.1903(a)(4)               
75.340....................................  75.1903 (a)(1) and (a)(4)   
75.362....................................  70.1900(a)                  
75.363....................................  70.1900(d)                  
75.371....................................  75.325(k)                   
75.380(d).................................  75.1916(a)                  
75.380(f).................................  75.1911(l)                  
75.513 and 75.513-1.......................  75.1910(f)                  
75.514....................................  75.1910(i)                  
75.515....................................  75.1910 (g) and (h)         
75.518 and 75.518-1.......................  75.1910(a)                  
75.523-3..................................  75.1909(c)                  
75.523-3(b)(2)............................  75.1909(c)(1)               
75.523-3(b)(3)............................  75.1909(c)(2)               
75.523-3(b)(4)............................  75.1909(c)(3)               
75.523-3(b)(5)............................  75.1909(c)(4)               
75.523-3(c)...............................  75.1909(c)(5)               
75.523-3(d)...............................  75.1909(d)                  
75.523-3(e)...............................  75.1909(e)                  
75.1000-3.................................  75.1906(j)                  
75.1100-2(f)..............................  75.1903(b)(1)               
75.1101-23................................  75.1912 (c) and (j)         
75.1107-3 through 75.1107-16..............  75.1911(l)                  
75.1107-3 through 75.1107-6 and 75.1107-8   75.1906(g)                  
 through 75.1107-16.                                                    
75.1107-4.................................  75.1912(d)                  
75.1107-13................................  75.1912(a)(1)               
75.1107-16................................  75.1912(h)                  
75.1403...................................  75.1916(a)                  
75.1404 and 75.1404-1.....................  75.1909(c)                  
40 CFR 79.................................  75.1901(c)                  
------------------------------------------------------------------------

III. Paperwork Reduction Act

    The information collection requirements contained in this rule have 
been submitted to the Office of Management and Budget (OMB) for review 
under the Paperwork Reduction Act of 1995 (44 U.S.C. 3501-3520), as 
implemented by OMB in regulations at 5 CFR 1320. No person may be 
required to respond to, or may be subjected to a penalty for failure to 
comply with, these information collection requirements until they have 
been approved by OMB and MSHA has displayed the assigned OMB control 
number. The OMB control number, when assigned, will be announced by 
separate notice in the Federal Register.

[[Page 55500]]

    The final rule addresses comments submitted to OMB and MSHA on the 
collection of information requirements in the proposed rule in the 
section-by-section discussions. In revising the requirements from those 
that appeared in the proposed rule, MSHA has evaluated the necessity 
and usefulness of the collection of information; reevaluated MSHA's 
estimate of the information collection burden, including the validity 
of the underlying methodology and assumptions; and minimized the 
information collection burden on respondents to the extent possible. 
This final rule also provides for the use of electronic storage and 
maintenance of records.
    Tables 1 through 4 show the distribution of information collection 
burden hours imposed by the requirements of the final rule. Tables 1 
and 2 pertain to manufacturers, Table 3 pertains to small mine 
operators, and Table 4 pertains to large mine operators.

                                             Table 1.--Estimated Annual New Burden Related to Manufacturers    
                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                 Operating            
 
                                                                                                       Number of     Capital        and      
          
                          Detail                              Number of     Hours per     Number of    responses     
costs     maintenance  Total hours
                                                             respondents    response      responses       per       annualized 
   costs                
                                                                                                       respondent   (rounded)   
(rounded)              
--------------------------------------------------------------------------------------------------------------------------------------------------------
                     Part 7--Subpart E                                                                                                            
     
                                                                                                                                                        
New Eng. (Perm.) \1\......................................           1.5       43                1.5            1           $0       
   $0           65
New Eng. (Perm.) \2\......................................           1.5        0.5              1.5            1            0        
  75            1
New Eng. (Nonperm.) \3\...................................           2.5       34                2.5            1            0     
      0           85
New Eng. (Nonperm.) \4\...................................           2.5        0.5              2.5            1            0     
    100            1
Existing Eng. (Nonperm.) \5\..............................          16          5               16              1          425   
        0           80
New Eng. (Nonperm.) \6\...................................           1         34.5              1              1            0      
 2,600           35
Existing Eng. (Nonperm.) \7\..............................           1         34.5              1              1          200   
        0           35
7.90......................................................         148          0.1667         148              1            0         
450           24
                                                                                                                                                        
                     Part 7--Subpart F                                                                                                            
     
                                                                                                                                                        
New Pow. Pack. (Perm.) \8\................................           1.5       43                1.5            1            0    
       0           65
Existing Pow. Pack. (Perm.) \9\...........................          33         12               33              1       
2,100            0          396
7.105.....................................................          20          0.1667          20              1            0           75 
          3
                                                          
---------------------------------------------------------------------------------------------
    Total Increases.......................................  ............  ............  ............  ...........        2,725       
3,300         790 
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ New diesel-powered engine models used in permissible equipment will require a maximum
fuel:air ratio test and a gaseous ventilation rate test
under 
  part 7, subpart E, instead of under existing part 36. Burden hours are shifted from existing part
36 to part 7, subpart E. The annual estimated       
  application costs of $4,850 are currently being incurred by manufacturers under part 36. Under
the final rule, such costs will continue to be incurred
  under part 7, subpart E, instead of under part 36. There are no new compliance costs.                   
                                             
\2\ New diesel-powered engine models used in permissible equipment that would have received
part 36 approval will require a particulate index
test.     
\3\ New diesel-powered engine models used in nonpermissible equipment that would have
received part 32 approval will require a maximum fuel
air ratio   
  test and a gaseous ventilation rate test under part 7, subpart E, instead of under part 32. As a
result of this rule, part 32 is deleted and burden   
  hours related to the tests on such engine models are shifted from deleted part 32 to part 7,
subpart E. The annual estimated application costs of     
  $6,375 are currently being incurred by manufacturers under part 32. Under the final rule, such
costs will continue to be incurred under part 7,       
  subpart E, instead of under part 32. There are no new compliance costs.                                        
                                      
\4\ New diesel-powered engine models used in nonpermissible equipment that would have
received part 32 approval will require a particulate
index test.  
\5\ Existing diesel-powered engine models used in nonpermissible equipment that have part 32
approval will require a one time particulate index
test.   
\6\ New diesel-powered engine models used in nonpermissible equipment that would not have
received part 32 approval will require a maximum
fuel air     
  ratio test, a gaseous ventilation rate test, and a particulate index test.                                              
                             
\7\ Existing diesel-powered engine models used in nonpermissible equipment that do not have
part 32 approval will require a one time maximum
fuel air   
  ratio test, a gaseous ventilation rate test, and a particulate index test.                                              
                             
\8\ New diesel-power package models used in permissible equipment will require approval under
part 7, subpart F, instead of under part 36. Burden hours 
  related to such approvals are shifted from part 36 to part 7, subpart F. The annual estimated
application costs of $4,850 are currently being incurred
  by manufacturers under part 36. Under the final rule, such costs will continue to be incurred
under part 7, subpart F, instead of under part 36. There
  are no new compliance costs.                                                                                                            
             
\9\ Diesel-power package models used in permissible equipment and previously approved under
part 36 could be reapproved and used to comply with the     
  requirement for a diesel power package pursuant to part 7, subpart F.                                             
                                   


                                       Table 2.--Estimated Annual Decrease in Burden Related to
Manufacturers \1\                                       
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                       Number of                 Operation   
          
                                                              Number of     Hours per     Number of    responses    
Capital        and                 
                          Detail                             respondents    response      responses       per         costs    
maintenance  Total hours
                                                                                                       respondent   annualized     costs   
            
--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Part 36                                                                                                                       
                                                                                                                                                        
New Eng. (Perm.) \2\......................................          1.5           43            1.5             1           $0       
   $0           65
New Pow. Pack. (Perm.) \3\................................                                                                                
             
                                                                    1.5           43            1.5             1            0            0         
 65
                          Part 32                                                                                                                       
                                                                                                                                                        
New Eng. (Nonperm.) \4\...................................          2.95          34.5          2.95            1            0  
         0          102
                                                          
---------------------------------------------------------------------------------------------
    Total Decreases.......................................  ............  ............  ............  ...........  ...........  ...........       
 232 
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Burden hours in this chart were developed and approved under the Paperwork Reduction Act
of 1980 (PRA 80). PRA 80 did not require costs to be       
  reported with burden hours. Thus no compliance costs are noted in this table.                               
                                         
\2\ New diesel-powered engine models used in permissible equipment will be approved under
part 7, subpart E, instead of part 36.                        
\3\ Diesel-power package models used in permissible equipment will be approved under part 7,
subpart F, instead of part 36.                             

[[Page 55501]]

                                                                                                                                                        
\4\ New diesel-powered engine models used in nonpermissible equipment will be approved under
part 7, subpart E, instead of part 32.                    



                    Table 3.-- Estimated Annual New Burden for Small Underground Coal Operators
That Use Diesel-Powered Equipment \1\                   
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                 Operation            
 
                                                                                                       Number of     Capital        and      
          
                          Detail                              Number of      Hours per    Number of    responses     
costs     maintenance  Total hours
                                                             respondents     response     responses       per       annualized 
   costs                
                                                                 \2\                                   respondent   (rounded)   
(rounded)              
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sec.  75.363.............................................             10         0.10            100           10       $2,100      
$3,800           10
Sec.  75.370.............................................             15         0.1667           15            1            0         
100            3
Sec.  75.1901(a).........................................              8         0.05            160           20            0         
100            8
Sec.  75.1904(b)(4)(i)...................................             15         0.0333           20            1         
<25            0            1
Sec.  75.1911 (i)&(j) \3\................................             15         0.3333          212           14          
 0        1,835           71
Sec.  75.1911 (i)&(j) \4\................................             15         1.0833           11           <1       
    0          915           12
Sec.  75.1912 (h)&(i) \5\................................             15         0.5833           20            1           
0          300           12
Sec.  75.1912 (h)&(i) \6\................................             15         1.0833            2           <1       
    0          100            2
Sec.  75.1914 (f)(1)&(h).................................             15     \7\ 1.1857          500           33       
    0       15,400          593
Sec.  75.1914 (f)(2)&(h).................................             15         0.0833          500           33        
   0        1,100           42
Sec.  75.1914(g)&(h) \8\.................................             15         2                30            2         
150            0           60
Sec.  75.1914 (g)&(h) \9\................................              1         2                 1            1            0  
        50            2
Sec.  75.1914 (g)(5)&(h).................................             15         0.25          1,480           98       
3,150       16,650          370
Sec.  75.1915(a).........................................             15         5                30            2          400           
0          150
Sec.  75.1915 (b)(5)&(c) \8\.............................             15        10                15            1         
400            0          150
Sec.  75.1915 (b)(5)&(c) \9\.............................              1         3                 1            1            0 
        125            3
                                                         
----------------------------------------------------------------------------------------------
    Total................................................  ..............  ............  ...........  ...........        6,225       40,475     
  1,489
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Small mines are those that employ 19 or fewer people.                                                                
                              
\2\ Respondents are the number of small mines.                                                                                 
                        
\3\ Section 75.1911(j) requires a record of Sec.  75.1911(i) weekly exams which find defects.        
                                                  
\4\ Section 75.1911(j) requires a record of Sec.  75.1911(i) manufacturer recommended exams
which find defects.                                         
\5\ Section 75.1912(i) requires a record of Sec.  75.1912(h) weekly exams which find defects.       
                                                   
\6\ Section 75.1912(i) requires a record of Sec.  75.1912(h) manufacturer recommended exams
which find defects.                                         
\7\ Represents a weighted average of hours based upon different exam hours for different types of
equipment.                                            
\8\ Reflects burden hours that will occur in the first year of implementation of the provision.         
                                               
\9\ Reflects burden hours that will occur annually, after the first year of implementation of the
provision.                                            


                     Table 4.--Estimated Annual New Burden for Large Underground Coal Operators
That Use Diesel-Powered Equipment
<SUP>1                     
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                 Operating            
 
                                                                                                       Number of     Capital        and      
          
                           Detail                              Number of     Hours per    Number of    responses     
costs     maintenance  Total hours
                                                               respondent    responses    responses       per       annualized 
   costs                
                                                                   <SUP>2                                   respondent  
(rounded)    (rounded)              
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sec.  75.363................................................          100        0.1834        1,000           10      $20,950   
  $40,825          184
Sec.  75.370................................................          158        0.3333          158            1            0       
1,975           52
Sec.  75.1901(a)............................................           79        0.05          1,975           25            0       
1,000           99
Sec.  75.1904(b)(4)(i)......................................          158        0.0333          494            3          250   
        0           16
Sec.  75.1911 (i) & (j) <SUP>3...................................          158        0.3333       14,810 
         94            0      128,340        4,936
Sec.  75.1911 (i) & (j) <SUP>4...................................          158        1.0833          592   
        4            0       51,335          641
Sec.  75.1912 (h) & (i) <SUP>5...................................          158        0.5833          100  
        <1            0        1,525           58
Sec.  75.1912 (h) & (i) <SUP>6...................................          158        1.0833            4    
      <1            0          350            5
Sec.  75.1914 (f)(1) & (h)..................................          158      <SUP>7 0.6234      
35,975          227            0      583,150       22,428
Sec.  75.1914 (f)(2) & (h)..................................          158        0.0833       35,975          227    
       0       77,925        2,997
Sec.  75.1914 (g) & (h) <SUP>8...................................          158        2               711     
      4        3,725            0        1,422
Sec.  75.1914 (g) & (h) <SUP>9...................................            5        2              22.5       
    4            0        1,700           45
Sec.  75.1914 (g)(5) & (h)..................................          158        0.25         52,350          331      
33,100      460,225       13,088
Sec.  75.1915(a)............................................          158        5             1,264            8            0     
236,000        6,320
Sec.  75.1915 (b)(5) & (c) <SUP>8................................          158       16               158   
        1        6,600            0        2,528
Sec.  75.1915 (b)(5) & (c) <SUP>9................................            5       16                 5       
    1            0        3,000           80
                                                            
-------------------------------------------------------------------------------------------
    Total...................................................  ...........  ............  ...........  ...........       64,625    1,587,350  
   54,899 
--------------------------------------------------------------------------------------------------------------------------------------------------------
<SUP>1 Large mines are those that employ 20 or more people.                                              
                                                   
<SUP>2 Respondents are the number of large mines.                                                              
                                             
<SUP>3 Section 75.1911(j) requires a record of Sec.  75.1911(i) weekly exams which find
defects.                                                             
<SUP>4 Section 75.1911(j) requires a record of Sec.  75.1911(i) manufacturer
recommended exams which find defects.                                           
<SUP>5 Section 75.1912(i) requires a record of Sec.  75. 1912(h) weekly exams which
find defects.                                                            
<SUP>6 Section 75.1912(i) requires a record of Sec.  75. 1912(h) manufacturer
recommended exams which find defects.                                          
<SUP>7 Represents a weighted average of hours based upon different exam hours for
different types of equipment.                                              
<SUP>8 Reflects burden hours that will occur in the first year of implementation of the
provision.                                                           
<SUP>9 Reflects burden hours that will occur annually, after the first year of
implementation of the provision.                                              


[[Page 55502]]

IV. Executive Order 12866 and Regulatory Flexibility Analysis

    Under E.O. 12866 [58 FR 51735, October 4, 1993] the Agency must 
determine whether the regulatory action is ``significant'' and subject 
to OMB review.
    E.O. 12866 defines ``significant regulatory action'' as one that is 
likely to result in a rule that may: (1) Have an annual effect on the 
economy of $100 million or more or adversely affect in a material way 
the economy, a sector of the economy, productivity, competition, jobs, 
the environment, public health or safety, or state, local, or tribal 
governments or communities; (2) create a serious inconsistency or 
otherwise interfere with an action taken or planned by another agency; 
(3) materially alter the budgetary impact of entitlements, grants, user 
fees, or loan programs or the right and obligations of recipients 
thereof; or (4) raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    OMB determined that this rule for diesel-powered equipment in 
underground coal mines is a ``significant regulatory action'' because 
MSHA's diesel particulate rulemaking for all mines has been designated 
``significant'' by the Agency. Although the diesel particulate 
rulemaking is separate and distinct from this final rule, OMB concluded 
that there is a sufficient enough relationship with this final rule to 
warrant its designation as significant. As such, MSHA has submitted 
this final rule to OMB for review.
    As required by E.O. 12866, the Agency determined costs and benefits 
associated with this final rule and has prepared a Final Regulatory 
Impact Analysis (RIA) and a Final Regulatory Flexibility Analysis 
(RFA). The RFA assesses benefits and costs of, and potentially 
effective and reasonably feasible alternatives to, the planned 
regulatory action. The RIA and RFA are available electronically and on 
request from MSHA through the address listed in the contact section at 
the beginning of this document. It is summarized below.

Benefits

    The final rule establishes comprehensive and integrated 
requirements governing diesel-powered equipment used in underground 
coal mines. Compliance with the rule will minimize fire, explosion, 
fuel handling, and fuel storage hazards. The health hazards of diesel 
engine exhaust are addressed by design, performance, and maintenance 
standards for diesel engines. Other safety hazards associated with the 
use of diesel-powered equipment in underground coal mines are also 
addressed.
    The final rule includes tests and specifications for MSHA approval 
of diesel engines. Clean operating engines will reduce miners' exposure 
to harmful emissions in the confined underground mine environment. The 
final rule sets test procedures and limits on the concentrations of 
carbon monoxide and oxides of nitrogen, and establishes the quantity of 
ventilating air necessary to dilute these exhaust contaminants to safe 
levels. The rule also contains tests and specifications for approval of 
diesel engine components, to ensure that diesel engines are fire and 
explosion-proof.
    The final rule also requires diesel-powered equipment to be 
equipped with certain safety features. These safety features will 
result in reduced fire hazards and lower the risk of accidents 
involving diesel-powered equipment. For example, the final rule 
requires diesel-powered equipment to have basic safety features, such 
as brakes and lights; fire protection features, including fuel, 
hydraulic, and electrical system protections; and properly designed, 
installed, and maintained fire suppression systems. In addition, the 
rule extends to diesel-powered equipment safety measures that already 
apply to electric-powered equipment that are proven to protect miners 
from cave-ins, such as cabs and canopies, and from explosions, such as 
methane monitors.
    The final rule provides for a systematic approach to the clean and 
safe operation of diesel-powered equipment. To accomplish this, the 
final rule sets standards for ventilation of diesel-powered equipment, 
and for routine sampling of toxic exhaust gases in the workplace, and 
requires the use of low sulfur diesel fuel to minimize emissions. It 
also requires that maintenance be performed by trained personnel to 
keep diesel equipment in proper operating condition.
    To ensure that the hazards associated with diesel fuel usage in the 
underground mine environment are properly controlled, the final rule 
includes requirements for the underground storage, transportation, and 
dispensing of diesel fuel. Design, tank capacity, and dispensing 
requirements are set for diesel fuel storage, as well as safety 
precautions and construction requirements for underground storage 
facilities and areas, including automatic fire suppression systems. 
These provisions will reduce the risk of fires involving diesel fuel.
    The final rule also extends several longstanding safety 
requirements for electric equipment to diesel-powered equipment. The 
final rule requires certain diesel equipment to be installed with 
methane monitors, providing miners with critical protection against 
methane explosions. The final rule also requires cabs and canopies to 
be installed on certain diesel-powered equipment, protecting miners 
from the dangers of roof and rib falls in the underground mine 
environment.

Cost of Compliance

    The compliance costs associated with the standards directly impact 
two industry groups: manufacturers of diesel-powered mining equipment 
and operators of underground coal mines. Part 7, subparts E and F 
relate to manufacturer costs and parts 70 and 75 relate to operator 
costs. The total compliance costs of the rule are estimated to be about 
$10.35 million per year, of which mine operators will incur about $10.3 
million per year and manufacturers will incur about $50,000 per year.
    The per-year cost of $10.3 million for mine operators consists of 
$4.9 million of annualized cost plus $5.4 million of annual costs. Of 
the $10.3 million, large mine operators will incur about $10.1 million, 
which consists of $4.8 million of annualized costs and $5.3 million of 
annual costs. Of the $10.3 million, small mine operators will incur 
about $210,800, which consists of $92,300 of annualized costs and 
$118,500 of annual costs. The per-year compliance costs for large and 
small mine operators is shown by section in Table 5.
    Manufacturers will incur costs of approximately $50,450 per year. 
The $50,450 consists of $15,900 of annualized costs and $34,550 of 
annual costs. The per-year compliance costs for manufacturers is shown 
by section in Table 6.

[[Page 55503]]



                                          Table 5.--Underground Coal Mine Compliance Costs for Diesel
Equipment                                         
                                                                   [Dollars  x  1,000]                                                            
     
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Large and small mines                    Large mines                       
Small mines          
                                              
---------------------------------------------------------------------------------------------------------
                   Standard                                                                                             (G) total                 
     
                                                 (A) total       (B)        (C)      (D) total       (E)        (F)       [Col.       
(H)        (I)   
                                                 [col. B+C]  annualized    annual    [col. E+F]  annualized    annual  
   H+I]    annualized    annual 
--------------------------------------------------------------------------------------------------------------------------------------------------------
70.1900.......................................      ($59.7)       $80.9   ($140.6)      ($77.7)       $75.8   ($153.5)    
 $18.0        $5.1      $12.9
75.325........................................       589.0          0       589.0        589.0          0       589.0         0      
    0          0  
75.1902.......................................        39.7         39.7       0           37.6         37.6       0           2.1      
  2.1        0  
75.1903.......................................        68.5         51.5      17.0         58.2         44.7      13.5        10.3 
       6.8        3.5
75.1904.......................................        32.7         32.7       0           31.2         31.2       0           1.5      
  1.5        0  
75.1905.......................................         2.4          2.4       0            2.3          2.3       0           0.1        
0.1        0  
75.1906.......................................       251.8        173.5      78.3        244.7        168.8      75.9        
7.1         4.7        2.4
75.1907.......................................     1,610.3      1,596.6      13.7      1,589.6      1,576.4      13.2       
20.7        20.2        0.5
75.1909.......................................     3,028.0      2,532.9     495.1      2,971.2      2,487.6     483.6      
 56.8        45.3       11.5
75.1910.......................................       117.4        117.4       0          116.1        116.1       0           1.3  
      1.3        0  
75.1911.......................................     1,221.3          0     1,221.3      1,203.2          0     1,203.2       
18.1         0         18.1
75.1912.......................................        20.0          0        20.0         16.5          0        16.5         3.5      
  0          3.5
75.1913.......................................         9.5          9.5       0            9.4          9.4       0           0.1        
0.1        0  
75.1914.......................................     2,769.3         40.1   2,729.2      2,700.0         36.8   2,663.2       
69.3         3.3       66.0
75.1915.......................................       573.9        155.4     418.5        572.3        153.9     418.4        
1.6         1.5        0.1
75.1916.......................................         8.7          8.7       0            8.4          8.4       0           0.3        
0.3        0  
                                              
---------------------------------------------------------------------------------------------------------
      Total...................................    10,282.8      4,841.3   5,441.5     10,072.0      4,749.0   5,323.0    
  210.8        92.3      118.5
--------------------------------------------------------------------------------------------------------------------------------------------------------


 Table 6.--Estimated Manufacturers Compliance Costs Associated With the 
   Regulations for Diesel-Powered Equipment in Underground Coal Mines   
------------------------------------------------------------------------
                                            Manufacturers costs         
                                  --------------------------------------
             Standard               (A) total       (B)                 
                                    [col. B+C]   annualized   (c) annual
------------------------------------------------------------------------
Part 7--Subpart E................      $42,650      $12,200      $30,450
Part 7--Subpart F................        7,800        3,700        4,100
                                  --------------------------------------
      Total Part 7...............       50,450       15,900       34,550
------------------------------------------------------------------------

Regulatory Flexibility Certification

    The Regulatory Flexibility Act requires that agencies developing 
regulatory standards evaluate and, where possible, include compliance 
alternatives that minimize any impact that would adversely affect small 
businesses. The use of diesel-powered equipment presents similar health 
and safety hazards in both large and small mining operations, and small 
mines will benefit from the requirements in the final rule. MSHA, 
therefore, has not exempted small mines from any provision of the final 
rule.
    Regulatory relief is not warranted because the final rule will not 
impose a substantial cost increase for small mines. MSHA has determined 
that these provisions will not have a significantly adverse impact upon 
a substantial number of small entities.

Small Business Regulatory Enforcement Fairness Act

    MSHA has determined that this final rule is not a ``major rule'' 
requiring prior approval by the Congress and the President under the 
Small Business Regulatory Enforcement Act of 1996 (5 U.S.C. Sec. 801 et 
seq.) (SBREFA), because it is not likely to result in: (1) an annual 
effect on the economy of $100 million or more; (2) a major increase in 
costs or prices for consumers, individual industries, federal, state, 
or local government agencies, or geographic regions; or (3) significant 
adverse effects on competition, employment, investment, productivity, 
innovation, or on the ability of United States-based enterprises to 
compete with foreign enterprises in domestic and export markets.
    The Agency will send copies of the final rule, preamble, and 
regulatory flexibility analysis to the President of the Senate, the 
Speaker of the House, and the General Counsel of the General Accounting 
Office.

V. Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995, Pub.L. 104-4, 
requires each federal agency to assess the effects of federal 
regulatory actions on state, local, and tribal governments and the 
private sector, other than to the extent such actions merely 
incorporate requirements specifically set forth in a statute. For 
purposes of the Unfunded Mandates Reform Act of 1995, as well as E.O. 
12875, this rule does not include any federal mandate that may result 
in increased expenditures by either State, local, and tribal 
governments, or increased expenditures by the private sector of more 
than $100 million on the private sector.

VI. Electronic Availability of Rulemaking Documents

    Electronic copies of the preamble and final rule, and the 
Regulatory Impact Analysis and Regulatory Flexibility Analysis are 
available on the Internet at the U.S. Department of Labor, Mine Safety 
and Health Administration's World Wide Web home page at http://
www.msha.gov. Instructions for accessing regulatory documents and 
information are as follows:
    From MSHA's home page select the menu item entitled ``Statutory and 
Regulatory Information.'' This will direct the search to the Statutory 
and Regulatory menu page. Then select the menu item entitled ``Federal 
Register Documents.'' This will direct the search

[[Page 55504]]

to the menu page for Federal Register Documents. The type of documents 
listed are proposed rules, final rules, meetings (Advisory Committees), 
Information Collection Requests, petitions for modifications, proposed 
policies, and miscellaneous notices. Select the menu item desired. To 
return to MSHA's home page, use the icon at the bottom of the page or 
the ``Back Button'' provided by your browser.

List of Subjects

30 CFR Part 7

    Diesel-powered equipment, Mine safety and health, Reporting and 
recordkeeping requirements.

30 CFR Parts 31 and 32

    Reporting and recordkeeping requirements, Research, Underground 
coal mines.

30 CFR Part 36

    Mine safety and health.

30 CFR Parts 70 and 75

    Diesel-powered equipment, Incorporations by reference, Mine safety 
and health, Underground coal mines, Reporting and recordkeeping 
requirements.

    Dated: October 15, 1996.
J. Davitt McAteer,
Assistant Secretary for Mine Safety and Health.

    Accordingly, chapter I of title 30, Code of Federal Regulations is 
amended as follows:

PART 7--TESTING BY APPLICANT OR THIRD PARTY

    1. The authority citation for part 7 continues to read as follows:

    Authority: 30 U.S.C. 957.

    2. New subparts E and F are added to part 7 to read as follows:

Subpart E--Diesel Engines Intended for Use in Underground Coal Mines

Sec.
7.81  Purpose and effective date.
7.82  Definitions.
7.83  Application requirements.
7.84  Technical requirements.
7.85  Critical characteristics.
7.86  Test equipment and specifications.
7.87  Test to determine the maximum fuel-air ratio.
7.88  Test to determine the gaseous ventilation rate.
7.89  Test to determine the particulate index.
7.90  Approval marking.
7.91  Post-approval product audit.
7.92  New technology.

Subpart E--Diesel Engines Intended for Use in Underground Coal 
Mines


Sec. 7.81  Purpose and effective date.

    Subpart A general provisions of this part apply to this subpart E. 
Subpart E establishes the specific engine performance and exhaust 
emission requirements for MSHA approval of diesel engines for use in 
areas of underground coal mines where permissible electric equipment is 
required and areas where non-permissible electric equipment is allowed. 
It is effective November 25, 1996.


Sec. 7.82  Definitions.

    In addition to subpart A definitions of this part, the following 
definitions apply in this subpart.
    Brake Power. The observed power measured at the crankshaft or its 
equivalent when the engine is equipped only with standard auxiliaries 
necessary for its operation on the test bed.
    Category A engines. Diesel engines intended for use in areas of 
underground coal mines where permissible electric equipment is 
required.
    Category B engines. Diesel engines intended for use in areas of 
underground coal mines where nonpermissible electric equipment is 
allowed.
    Corrosion-resistant material. Material that has at least the 
corrosion-resistant properties of type 304 stainless steel.
    Diesel engine. Any compression ignition internal combustion engine 
using the basic diesel cycle where combustion results from the spraying 
of fuel into air heated by compression.
    Exhaust emission. Any substance emitted to the atmosphere from the 
exhaust port of the combustion chamber of a diesel engine.
    Intermediate speed. Maximum torque speed if it occurs between 60 
percent and 75 percent of rated speed. If the maximum torque speed is 
less than 60 percent of rated speed, then the intermediate speed shall 
be 60 percent of the rated speed. If the maximum torque speed is 
greater than 75 percent of the rated speed, then the intermediate speed 
shall be 75 percent of rated speed.
    Low idle speed. The minimum no load speed as specified by the 
engine manufacturer.
    Maximum torque speed. The speed at which an engine develops maximum 
torque.
    Operational range. All speed and load (including percent loads) 
combinations from the rated speed to the minimum permitted engine speed 
at full load as specified by the engine manufacturer.
    Particulates. Any material collected on a specified filter medium 
after diluting exhaust gases with clean, filtered air at a temperature 
of less than or equal to 125 deg. F (52 deg. C), as measured at a point 
immediately upstream of the primary filter. This is primarily carbon, 
condensed hydrocarbons, sulfates, and associated water.
    Percent load. The fraction of the maximum available torque at an 
engine speed.
    Rated horsepower. The nominal brake power output of a diesel engine 
as specified by the engine manufacturer with a specified production 
tolerance. For laboratory test purposes, the fuel pump calibration for 
the rated horsepower must be set between the nominal and the maximum 
fuel tolerance specification.
    Rated speed. Speed at which the rated power is delivered, as 
specified by the engine manufacturer.
    Steady-state condition. Diesel engine operating condition which is 
at a constant speed and load and at stabilized temperatures and 
pressures.
    Total oxides of nitrogen. The sum total of the measured parts per 
millions (ppm) of nitric oxide (NO) plus the measured ppm of nitrogen 
dioxide (NO<INF>2).


Sec. 7.83  Application requirements.

    (a) An application for approval of a diesel engine shall contain 
sufficient information to document compliance with the technical 
requirements of this subpart and specify whether the application is for 
a category A engine or category B engine.
    (b) The application shall include the following engine 
specifications--
    (1) Model number;
    (2) Number of cylinders, cylinder bore diameter, piston stroke, 
engine displacement;
    (3) Maximum recommended air inlet restriction and exhaust 
backpressure;
    (4) Rated speed(s), rated horsepower(s) at rated speed(s), maximum 
torque speed, maximum rated torque, high idle, minimum permitted engine 
speed at full load, low idle;
    (5) Fuel consumption at rated horsepower(s) and at the maximum 
rated torque;
    (6) Fuel injection timing; and
    (7) Performance specifications of turbocharger, if applicable.
    (c) The application shall include dimensional drawings (including 
tolerances) of the following components specifying all details 
affecting the technical requirements of this subpart. Composite 
drawings specifying the required construction details may be submitted 
instead of individual drawings of the following components--

[[Page 55505]]

    (1) Cylinder head;
    (2) Piston;
    (3) Inlet valve;
    (4) Exhaust valve;
    (5) Cam shaft--profile;
    (6) Fuel cam shaft, if applicable;
    (7) Injector body;
    (8) Injector nozzle;
    (9) Injection fuel pump;
    (10) Governor;
    (11) Turbocharger, if applicable;
    (12) Aftercooler, if applicable;
    (13) Valve guide;
    (14) Cylinder head gasket; and
    (15) Precombustion chamber, if applicable.
    (d) The application shall include a drawing showing the general 
arrangement of the engine.
    (e) All drawings shall be titled, dated, numbered, and include the 
latest revision number.
    (f) When all necessary testing has been completed, the following 
information shall be submitted:
    (1) The gaseous ventilation rate for the rated speed and 
horsepower.
    (2) The particulate index for the rated speed and horsepower.
    (3) A fuel deration chart for altitudes for each rated speed and 
horsepower.


Sec. 7.84  Technical requirements.

    (a) Fuel injection adjustment. The fuel injection system of the 
engine shall be constructed so that the quantity of fuel injected can 
be controlled at a desired maximum value. This adjustment shall be 
changeable only after breaking a seal or by altering the design.
    (b) Maximum fuel-air ratio. At the maximum fuel-air ratio 
determined by Sec. 7.87 of this part, the concentrations (by volume, 
dry basis) of carbon monoxide (CO) and oxides of nitrogen (NO<INF>X) in 
the undiluted exhaust gas shall not exceed the following:
    (1) There shall be no more than 0.30 percent CO and no more than 
0.20 percent NO<INF>X for category A engines.
    (2) There shall be no more than 0.25 percent CO and no more than 
0.20 percent NO<INF>X for category B engines.
    (c) Gaseous emissions ventilation rate. Ventilation rates necessary 
to dilute gaseous exhaust emissions to the following values shall be 
determined under Sec. 7.88 of this part:

Carbon dioxide.........................  -5000 ppm                      
Carbon monoxide........................  -50 ppm                        
Nitric oxide...........................  -25 ppm                        
Nitrogen dioxide.......................  -5 ppm                         
                                                                        

A gaseous ventilation rate shall be determined for each requested speed 
and horsepower rating as described in Sec. 7.88(b) of this part.
    (d) Fuel deration. The fuel rates specified in the fuel deration 
chart shall be based on the tests conducted under paragraphs (b) and 
(c) of this section and shall ensure that the maximum fuel:air (f/a) 
ratio determined under paragraph (b) of this section is not exceeded at 
the altitudes specified in the fuel deration chart.
    (e) Particulate index. For each rated speed and horsepower 
requested, the particulate index necessary to dilute the exhaust 
particulate emissions to 1 mg/m<SUP>3 shall be determined under 
Sec. 7.89 of this part.


Sec. 7.85  Critical characteristics.

    The following critical characteristics shall be inspected or tested 
on each diesel engine to which an approval marking is affixed--
    (a) Fuel rate is set properly; and
    (b) Fuel injection pump adjustment is sealed, if applicable.


Sec. 7.86  Test equipment and specifications.

    (a) Dynamometer test cell shall be used in determining the maximum 
f/a ratio, gaseous ventilation rates, and the particulate index.
    (1) The following testing devices shall be provided:
    (i) An apparatus for measuring torque that provides an accuracy of 
<plus-minus>2.0 percent based on the engine's maximum value;
    (ii) An apparatus for measuring revolutions per minute (rpm) that 
provides an accuracy of <plus-minus>2.0 percent based on the engine's 
maximum value;
    (iii) An apparatus for measuring temperature that provides an 
accuracy of <plus-minus>4 deg. F (2 deg. C) of the absolute value 
except for the exhaust gas temperature device that provides an accuracy 
of <plus-minus>27 deg. F (15 deg. C);
    (iv) An apparatus for measuring intake and exhaust restriction 
pressures that provides an accuracy of <plus-minus>5 percent of 
maximum;
    (v) An apparatus for measuring atmospheric pressure that provides 
an accuracy of <plus-minus>0.5 percent of reading;
    (vi) An apparatus for measuring fuel flow that provides an accuracy 
of <plus-minus>2 percent based on the engine's maximum value;
    (vii) An apparatus for measuring the inlet air flow rate of the 
diesel engine that provides an accuracy of <plus-minus>2 percent based 
on the engine's maximum value; and
    (viii) For testing category A engines, an apparatus for metering in 
1.0 <plus-minus>0.1 percent, by volume, of methane (CH<INF>4) into the 
intake air system shall be provided.
    (2) The test fuel specified in Table E-1 shall be a low volatile 
hydrocarbon fuel commercially designated as ``Type 2-D'' grade diesel 
fuel. The fuel may contain nonmetallic additives as follows: Cetane 
improver, metal deactivator, antioxidant, dehazer, antirust, pour 
depressant, dye, dispersant, and biocide.

               Table E-1.--Diesel Test Fuel Specifications              
------------------------------------------------------------------------
              Item                     ASTM              Type 2-D       
------------------------------------------------------------------------
Cetane number..................  D613             40-48.                
Cetane index...................  D976             40-48.                
Distillation range:                                                     
    IBP  deg.F.................  D86              340-400.              
        ( deg.C)...............  ...............  (171.1-204.4).        
    10 pct. point,  deg.F......  D86              400-460.              
        ( deg.C)...............  ...............  (204.4-237.8).        
    50 pct. point,  deg.F......  D86              470.540.              
        ( deg.C)...............  ...............  (243.3-282.2).        
    90 pct. point,  deg.F......  D86              560-630.              
        ( deg.C)...............  ...............  (293.3-332.2).        
    EP,  deg.F.................  D86              610-690.              
        ( deg.C)...............  ...............  (321.1-365.6).        
Gravity,  deg.API..............  D287             32-37.                
Total sulfur, pct..............  D2622            0.03-0.05.            
Hydrocarbon composition:                                                
    Aromatics, pct.............  D1319            27 minimum.           
    Paraffins, naphthenes,       D1319            Remainder.            
     olefins.                                                           

[[Page 55506]]

                                                                        
Flashpoint, minimum,  deg.F....  93               130.                  
    ( deg.C)...................  ...............  (54.4).               
Viscosity, centistokes.........  445              2.0-3.2.              
------------------------------------------------------------------------

    (3) The test fuel temperature at the inlet to the diesel engine's 
fuel injection pump shall be controlled to the engine manufacturer's 
specification.
    (4) The engine coolant temperature (if applicable) shall be 
maintained at normal operating temperatures as specified by the engine 
manufacturer.
    (5) The charge air temperature and cooler pressure drop (if 
applicable) shall be set to within <plus-minus>7 deg. F(4 deg. C) and 
<plus-minus>0.59 inches Hg (2kPa) respectively, of the manufacturer's 
specification.
    (b) Gaseous emission sampling system shall be used in determining 
the gaseous ventilation rates.
    (1) The schematic of the gaseous sampling system shown in Figure E-
1 shall be used for testing category A engines. Various configurations 
of Figure E-1 may produce equivalent results. The components in Figure 
E-1 are designated as follows--
    (i) Filters--F1, F2, F3, and F4;
    (ii) Flowmeters--FL1, FL2, FL3, FL4, FL5, FL6, and FL7;
    (iii) Upstream Gauges--G1, G2, and G5;
    (iv) Downstream Gauges--G3, G4, and G6;
    (v) Pressure Gauges--P1, P2, P3, P4, P5, and P6;
    (vi) Regulators--R1, R2, R3, R4, R5, R6, and R7;
    (vii) Selector Valves--V1, V2, V3, V4, V6, V7, V8, V15, and V19;
    (viii) Heated Selector Valves--V5, V13, V16, and V17;
    (ix) Flow Control Valves--V9, V10, V11 and V12;
    (x) Heated Flow Control Valves--V14 and V18;
    (xi) Pump--Sample Transfer Pump;
    (xii) Temperature Sensor--(T1);
    (xiii) Dryer--D1 and D2; and
    (xiv) Water traps--WT1 and WT2.
    (A) Water removal from the sample shall be done by condensation.
    (B) The sample gas temperature or dew point shall be monitored 
either within the water trap or downstream of the water trap and shall 
not exceed 45 deg. F (7 deg. C).
    (C) Chemical dryers are not permitted.

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[[Page 55508]]

    (2) The schematic of the gaseous sampling system shown in Figure E-
2 shall be used for testing category B engines. Various configurations 
of Figure E-2 may produce equivalent results. The components are 
designated as follows--
    (i) Filters--F1, F2, F3, and F4;
    (ii) Flowmeters--FL1, FL2, FL3, and FL4;
    (iii) Upstream Gauges--G1, and G2;
    (iv) Downstream Gauges--G3, and G4;
    (v) Pressure Gauges--P1, P2, P3, and P4;
    (vi) Regulators--R1, R2, R3, and R4;
    (vii) Selector Valves--V1, V2, V3, V4, V6, and V7;
    (viii) Heated Selector Valves--V5, V8, and V12;
    (ix) Flow Control Valves--V9, V10, V11;
    (x) Heated Flow Control Valves--V13;
    (xi) Pump--Sample Transfer Pump;
    (xii) Temperature Sensor--(T1); and
    (xiii) Water traps--WT1 and WT2.
    (A) Water removal from the sample shall be done by condensation.
    (B) The sample gas temperature or dew point shall be monitored 
either within the water trap or downstream of the water trap and shall 
not exceed 45  deg.F (7  deg.C).
    (C) Chemical dryers are not permitted.
    (3) All components or parts of components that are in contact with 
the sample gas or corrosive calibration gases shall be corrosion-
resistant material.

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[[Page 55510]]

    (4) All analyzers shall obtain the sample to be analyzed from the 
same sample probe.
    (5) CO and CO<INF>2 measurements shall be made on a dry basis.
    (6) Calibration or span gases for the NO<INF>X measurement system 
shall pass through the NO<INF>2 to NO converter.
    (7) A stainless steel sample probe shall be straight, closed-end, 
multi-holed, and shall be placed inside the exhaust pipe.
    (i) The probe length shall be at least 80 percent of the diameter 
of the exhaust pipe.
    (ii) The inside diameter of the sample probe shall not be greater 
than the inside diameter of the sample line.
    (iii) The heated sample line shall have a 0.197 inch (5 mm) minimum 
and a 0.53 inch (13.5 mm) maximum inside diameter.
    (iv) The wall thickness of the probe shall not be greater than 
0.040 inch (1 mm).
    (v) There shall be a minimum of 3 holes in 3 different radial 
planes sized to sample approximately the same flow.
    (8) The sample probe shall be located in the exhaust pipe at a 
minimum distance of 1.6 feet (0.5 meters) or 3 times the diameter of 
the exhaust pipe, whichever is the larger, from the exhaust manifold 
outlet flange or the outlet of the turbocharger. The exhaust gas 
temperature at the sample probe shall be a minimum of 158 deg. F 
(70 deg. C).
    (9) The maximum allowable leakage rate on the vacuum side of the 
analyzer pump shall be 0.5 percent of the in-use flow rate for the 
portion of the system being checked.
    (10) General analyzer specifications.
    (i) The total measurement error, including the cross sensitivity to 
other gases, (paragraphs (b)(11)(ii), (b)(12)(iii), (b)(13)(iii), and 
(b)(13)(iv) of this section), shall not exceed <plus-minus>5 percent of 
the reading or <plus-minus>3.5 percent of full scale, whichever is 
smaller. For concentrations of less than 100 ppm the measurement error 
shall not exceed <plus-minus>4 ppm.
    (ii) The repeatability, defined as 2.5 times the standard deviation 
of 10 repetitive responses to a given calibration or span gas, must be 
no greater than <plus-minus>1 percent of full scale concentration for 
each range used above 155 parts per million (ppm) or parts per million 
equivalent carbon (ppmC) or <plus-minus>2 percent of each range used 
below 155 ppm (or ppmC).
    (iii) The analyzer peak to peak response to zero and calibration or 
span gases over any 10 second period shall not exceed 2 percent of full 
scale on all ranges used.
    (iv) The analyzer zero drift during a 1-hour period shall be less 
than 2 percent of full scale on the lowest range used. The zero-
response is the mean response, including noise, to a zero gas during a 
30-second time interval.
    (v) The analyzer span drift during a 1-hour period shall be less 
than 2 percent of full scale on the lowest range used. The analyzer 
span is defined as the difference between the span response and the 
zero response. The span response is the mean response, including noise, 
to a span gas during a 30-second time interval.
    (11) CO and CO<INF>2 analyzer specifications.
    (i) Measurements shall be made with nondispersive infrared (NDIR) 
analyzers.
    (ii) For the CO analyzer, the water and CO<INF>2 interference shall 
be less than 1 percent of full scale for ranges equal to or greater 
than 300 ppm (3 ppm for ranges below 300 ppm) when a CO<INF>2 span gas 
concentration of 80 percent to 100 percent of full scale of the maximum 
operating range used during testing is bubbled through water at room 
temperature.
    (12) For NO<INF>X analysis using a chemiluminescence (CL) analyzer 
the following parameters shall apply:
    (i) From the sample point to the NO<INF>2 to NO converter, the 
NO<INF>X sample shall be maintained between 131 deg. F (55 deg. C) and 
392 deg. F (200 deg. C).
    (ii) The NO<INF>2 to NO converter efficiency shall be at least 90 
percent.
    (iii) The quench interference from CO<INF>2 and water vapor must be 
less than 3.0 percent.
    (13) For NO<INF>X analysis using an NDIR analyzer system the 
following parameters shall apply:
    (i) The system shall include a NO<INF>2 to NO converter, a water 
trap, and a NDIR analyzer.
    (ii) From the sample point to the NO<INF>2 to NO converter, the 
NO<INF>X sample shall be maintained between 131 deg. F (55 deg. C) and 
392 deg. F (200 deg. C).
    (iii) The minimum water rejection ratio (maximum water 
interference) for the NO<INF>X NDIR analyzer shall be 5,000:1.
    (iv) The minimum CO<INF>2 rejection ratio (maximum CO<INF>2 
interference) for the NO<INF>X NDIR analyzer shall be 30,000:1.
    (14) When CH<INF>4 is measured using a heated flame ionization 
detector (HFID) the following shall apply:
    (i) The analyzer shall be equipped with a constant temperature oven 
that houses the detector and sample-handling components.
    (ii) The detector, oven, and sample-handling components shall be 
suitable for continuous operation at temperatures of 374 deg. F 
(190 deg. C) <plus-minus> 18 deg. F (10 deg. C).
    (iii) The analyzer fuel shall contain 40 <plus-minus> 2 percent 
hydrogen. The balance shall be helium. The mixture shall contain 
<ls-thn-eq> 1 part per million equivalent carbon (ppmC), and 
<ls-thn-eq> 400 ppm CO.
    (iv) The burner air shall contain < 2 ppmC hydrocarbon.
    (v) The percent of oxygen interference shall be less than 5 
percent.
    (15) An NDIR analyzer for measuring CH<INF>4 may be used in place 
of the HFID specified in paragraph (b)(14) of this section and shall 
conform to the requirements of paragraph (b)(10) of this section. 
Methane measurements shall be made on a dry basis.
    (16) Calibration gas values shall be traceable to the National 
Institute for Standards and Testing (NIST), ``Standard Reference 
Materials'' (SRM's). The analytical accuracy of the calibration gas 
values shall be within 2.0 percent of NIST gas standards.
    (17) Span gas values shall be traceable to NIST SRM's. The 
analytical accuracy of the span gas values shall be within 2.0 percent 
of NIST gas standards.
    (18) Calibration or span gases for the CO and CO<INF>2 analyzers 
shall have purified nitrogen as a diluent. Calibration or span gases 
for the CH<INF>4 analyzer shall be CH<INF>4 with purified synthetic air 
or purified nitrogen as diluent.
    (19) Calibration or span gases for the NO<INF>X analyzer shall be 
NO with a maximum NO<INF>2 concentration of 5 percent of the NO 
content. Purified nitrogen shall be the diluent.
    (20) Zero-grade gases for the CO, CO<INF>2, CH<INF>4 , and NO<INF>X 
analyzers shall be either purified synthetic air or purified nitrogen.
    (21) The allowable zero-grade gas (purified synthetic air or 
purified nitrogen) impurity concentrations shall not exceed <ls-thn-eq> 
1ppm C, <ls-thn-eq> 1 ppm CO, <ls-thn-eq> 400 ppm CO<INF>2, and 
<ls-thn-eq> 0.1 ppm NO.
    (22) The calibration and span gases may also be obtained by means 
of a gas divider. The accuracy of the mixing device must be such that 
the concentration of the diluted calibration gases are within 2 
percent.
    (c) Particulate sampling system shall be used in determining the 
particulate index. A schematic of a full flow (single dilution) 
particulate sampling system for testing under this subpart is shown in 
Figures E-3 and E-4.
    (1) The dilution system shall meet the following parameters:
    (i) Either a positive displacement pump (PDP) or a critical flow 
venturi (CFV) shall be used as the pump/mass measurement device shown 
in Figure E-3.

[[Page 55511]]

    (ii) The total volume of the mixture of exhaust and dilution air 
shall be measured.
    (iii) All parts of the system from the exhaust pipe up to the 
filter holder, which are in contact with raw and diluted exhaust gas, 
shall be designed to minimize deposition or alteration of the 
particulate.
    (iv) All parts shall be made of electrically conductive materials 
that do not react with exhaust gas components.
    (v) All parts shall be electrically grounded to prevent 
electrostatic effects.
    (vi) Systems other than full flow systems may also be used provided 
they yield equivalent results where:
    (A) A seven sample pair (or larger) correlation study between the 
system under consideration and a full flow dilution system shall be run 
concurrently.
    (B) Correlation testing is to be performed at the same laboratory, 
test cell, and on the same engine.
    (C) The equivalency criterion is defined as a <plus-minus> 5 
percent agreement of the sample pair averages.
    (2) The mass of particulate in the exhaust shall be collected by 
filtration. The exhaust temperature immediately before the primary 
particulate filter shall not exceed 125 deg. F (52.0 deg. C).
    (3) Exhaust system backpressure shall not be artificially lowered 
by the PDP, CFV systems or dilution air inlet system. Static exhaust 
backpressure measured with the PDP or CFV system operating shall remain 
within <plus-minus> 0.44 inches Hg (1.5 kPa) of the static pressure 
measured without being connected to the PDP or CFV at identical engine 
speed and load.
    (4) The gas mixture temperature shall be measured at a point 
immediately ahead of the pump or mass measurement device.
    (i) Using PDP, the gas mixture temperature shall be maintained 
within <plus-minus> 10 deg. F (6.0 deg. C) of the average operating 
temperature observed during the test, when no flow compensation is 
used.
    (ii) Flow compensation can be used provided that the temperature at 
the inlet to the PDP does not exceed 122 deg. F (50 deg. C).
    (iii) Using CFV, the gas mixture temperature shall be maintained 
within <plus-minus> 20 deg. F (11 deg. C) of the average operating 
temperature observed during the test, when no flow compensation is 
used.
    (5) The heat exchanger shall be of sufficient capacity to maintain 
the temperature within the limits required above and is optional if 
electronic flow compensation is used.
    (6) When the temperature at the inlet of either the PDP or CFV 
exceeds the limits stated in either paragraphs (c)(4)(i) or (c)(4)(iii) 
of this section, an electronic flow compensation system shall be 
required for continuous measurement of the flow rate and control of the 
proportional sampling in the particulate sampling system.
    (7) The flow capacity of the system shall be large enough to 
eliminate water condensation.

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