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MSHA Federal Register Document
Rules and Regulations

Volume 61, Number 18, Page 2543


[Page 9763]]
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Part III

Department of Labor

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Mine Safety and Health Administration
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30 CFR Part 75

Safety Standards for Underground Coal Mine Ventilation; Final Rule

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Department of Labor

Mine Safety and Health Administration

30 CFR Part 75

RIN 1219-AA11


Safety Standards for Underground Coal Mine Ventilation

AGENCY: Mine Safety and Health Administration, (MSHA) Labor.

ACTION: Final rule.

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SUMMARY: This final rule revises the Mine Safety and Health 
Administration's (MSHA's) existing safety standards for ventilation of 
underground coal mines. After publication of the existing standards, 
the U.S. Court of Appeals in the D.C. Circuit stayed the application of 
one standard and MSHA stayed two standards. The rule revises these 
stayed provisions, revises or clarifies other provisions in the rule 
and includes some new provisions. The provisions of the final rule are 
expected to decrease the potential for fatalities, particularly 
accidents which can result in multiple deaths, and to reduce the risk 
of injuries and illnesses in underground coal mines. For the 
convenience of the reader, MSHA has published the full text of the 
ventilation standards for underground coal mines in this document.

EFFECTIVE DATE: The final rule is effective June 10, 1996.

FOR FURTHER INFORMATION CONTACT: Patricia W. Silvey, Director, Office 
of Standards, Regulations and Variances, MSHA, phone 703/ 235-1910; fax 
703/235-5551.

SUPPLEMENTARY INFORMATION:

I. Background

    The mining of coal underground has historically been recognized as 
one of the more hazardous occupations in the world. It is a universally 
recognized principle of underground coal mine safety that there must be 
proper ventilation of the mine. Indeed, no aspect of safety in 
underground coal mining is more fundamental than proper ventilation. A 
basic tenet of mining safety states that ventilation must be 
sufficient: (1) To dilute, render harmless and carry away the hazardous 
components of mine air, such as potentially explosive methane; and (2) 
to provide necessary levels of oxygen to the miners' working 
environment. Ventilation safety programs are designed around this 
philosophy. The history of mining is replete with tragic incidents 
where one aspect or another of a necessary ventilation safety 
protection was either not in place or not followed, with disastrous 
results. Examples include the explosion at the Monogah mine in 1907 in 
which 362 miners perished, the worst mining disaster in the history of 
the United States. Other more recent examples include the Farmington 
disaster in 1968 in which 78 miners died, the Scotia mine in 1976 where 
26 died, Grundy No. 17 in 1981 where 13 died, Wilberg in 1984 where 27 
died, Pyro in 1989 with 10 deaths and Southmountain in 1992 where 8 
miners died. In 1969 and again in 1977, Congress recognized the hazards 
of improper ventilation and established a role for the government in 
addressing ventilation hazards. MSHA, with the cooperation of labor and 
industry, has met with a large measure of success in reducing the 
accidents, injuries and fatalities that have resulted from poor 
ventilation practices. For example, explosions and fires in a 29 year 
period from 1940 to 1968 resulted in the deaths of 491 miners. Since 
the passage of the Federal Coal Mine Health and Safety Act of 1969, 178 
explosion and fire related deaths have occurred. While MSHA recognizes 
that this number is still unacceptable, the significant reduction in 
loss of life cannot be ignored. To a great extent, the framework for 
this success has been the implementation of effective ventilation 
standards.
    Preventing recurrence of disasters like those of the past remains 
the top priority of MSHA. MSHA believes that a serious commitment by 
management, labor, and government is necessary to develop effective, 
yet reasonable and practical regulations that protect the safety and 
health of our nation's miners. MSHA anticipates that this rulemaking, 
which revises portions of the comprehensive ventilation rule published 
in 1992 (57 FR 20868, May 15, 1992) and adds new provisions, will bring 
the coal mining industry closer to that objective.
    The comprehensive 1992 ventilation rulemaking was closely followed 
by interested industry and labor groups, who frequently expressed 
divergent views on approaches to resolving ventilation issues. Certain 
commenters exercised their right to challenge the rule and the U.S. 
Court of Appeals for the D.C. Circuit Court stayed one provision 
relating to oxygen and carbon dioxide in the bleeder entries. MSHA held 
a series of informational meetings around the country during which it 
explained the application of the rule. In so doing, MSHA listened to 
many questions about the implementation of the rule. MSHA was sensitive 
to the views expressed at these meetings and gave serious consideration 
to these issues. Some of these comments became the basis for portions 
of this rulemaking. Internal discussions of MSHA's experience with the 
implementation of the rule led MSHA to include still other issues in 
this rulemaking. In fact, MSHA stayed the application of two additional 
provisions in response to potential problems pointed out by interested 
parties. These stayed provisions relate to actions following the 
stoppage of the main mine fan with persons underground and to a 
potential fire hazard from the enclosure of compressors in a 
noncombustible structure. MSHA addresses these issues in the 
rulemaking. Once MSHA decided that it was going to proceed with a 
rulemaking to address these issues, it added other provisions to the 
package to allow all parties an opportunity to comment where they 
expressed the view that they had insufficient opportunity to comment on 
the existing rule (The comprehensive rule that was published in the 
Federal Register on May 15, 1992). The rule MSHA proposed also included 
issues raised by parties in litigation challenging the existing rule. 
MSHA anticipates that the final rule should resolve matters included in 
the challenge raised by the litigation of the existing rule. Finally, 
in an effort to address confusion that seemed to exist with certain 
provisions of the existing ventilation rule promulgated in May of 1992, 
MSHA either proposed clarifications to the existing rule or discussed 
the affected provisions in the preambles to the proposed and final 
rules in an effort to clarify them.
    The issues in the rulemaking are complex and highly technical. 
Comments to the proposal (published on May 19, 1994, 59 FR 26536) and 
comments following the public hearings (held in September and October 
1994, in Price, Utah, Logan, West Virginia, and Washington, 
Pennsylvania) were extensive. One party alone submitted over two 
thousand pages of written comments and over 275 exhibits. Not only were 
the safety issues involved complex, but in many cases, MSHA's task was 
made more difficult by hearing diametrically opposed viewpoints.

Major Improvements in the Final Rule

    The final rule provides a number of significant improvements to the 
existing ventilation regulations. For example, the final rule provides 
for the electronic storage of records. A major portion of the mining 
industry has this capability at the present time through computer 
technology at the mine site. Electronic 

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record retention can reduce the cost of storage and maintenance of 
records and provide for ease in access and transfer of information 
without reducing the protection afforded miners. Additionally, having 
records electronically stored can facilitate trend analysis, allowing 
for earlier detection and correction of potential hazards.
    The final rule also requires pressure recorders or an option of the 
use of a fan monitoring system on main mine fans at all mines. This 
represents a major step toward monitoring the mine fans controlling the 
ventilation at the mines and helps assure that the miners have 
uncontaminated air at all times. The final rule also provides for 
methane testing at the face during mining operations. This technology 
is especially useful for taking methane tests during extended cut 
mining operations. The methane testing evaluates air flow to the face 
to determine that methane is sufficiently diluted, rendered harmless, 
and carried away so as to reduce or eliminate the hazards associated 
with methane liberated during mining operations.
    Other improvements in the rule include revisions to the three 
stayed provisions in the existing rule. Air quality levels for oxygen 
and carbon dioxide in bleeders are established to protect mine 
examiners who are required to travel to determine if the bleeders are 
functioning properly. A second stayed provision is revised to limit the 
use of transportation equipment during the withdrawal of miners after 
an unintentional fan stoppage. This revision to the existing rule 
reduces the likelihood of an ignition from methane that can accumulate 
during the fan stoppage. The third stayed provision is revised to allow 
the option of attending rather than housing compressors in a 
noncombustible enclosure. The hazards associated with the operation of 
compressors in underground mines were demonstrated at the Wilberg mine 
disaster, where 27 people lost their lives as a result of a compressor 
fire.
    This final rule provides for an alert and alarm device to be 
located outside of noncombustible structures housing electrical 
installations. The alert and alarm assures that miners are made aware 
of a problem in time to extinguish a fire or safely evacuate an area or 
the mine as necessary for safety. Another change to the existing rule 
involves miners or their representatives in the mine ventilation plan 
approval process before the plan is submitted for approval. This 
provides for the opportunity for input from those having first hand 
knowledge in the particular mining conditions and practices that impact 
the plan approval.
    Other safety enhancements from the existing rule include: requiring 
the use of extendable probes to conduct methane tests at deep cuts; 
requiring on-shift examinations on other than coal producing shifts; 
and accepting a performance test to determine minimum dimensions at 
certain locations in escapeways.
    Finally, the final rule clarifies existing regulations that were 
considered vague by some parties or were misunderstood. For example, 
the final rule provides that certified pumpers can conduct their own 
examination rather than requiring the examination to be conducted 
during the preshift segment of the mining operation.
    To serve the interests of the mining community, MSHA has 
republished the full text of subpart D of 30 CFR part 75 as it will 
read upon promulgation of this rule.

II. Discussion of the Final Rule

A. General Discussion

    In developing the final rule, MSHA has made every effort to address 
the comments received during the rulemaking, and to develop practical 
requirements for real safety problems. Both the costs and the benefits 
of each standard were also considered. In addition, each standard, as 
well as revisions and deletions, was carefully considered against the 
statutory requirement that nothing in the final rule shall reduce the 
protection afforded miners by an existing mandatory health or safety 
standard. Where appropriate, MSHA has provided for a phase in period to 
allow mine operators time to effectively plan and implement the 
necessary changes.
    MSHA carefully analyzed the comments received and responded in many 
instances by revising the proposed requirements. For example, unlike 
the proposal, the final rule does not require the second level 
countersigning of records; allows the use of nonpermissible equipment 
when conducting an examination upon restart of a fan following 
unintentional fan stoppages, and requires pressure recording devices or 
an option of the use of a fan monitoring system to be used on all main 
mine fans.
    Several commenters strongly urged MSHA to proceed in this 
rulemaking on the issue of using air coursed through the belt entries 
("belt air") to ventilate the working face. MSHA has completed its 
consideration of the Report of the Secretary's Advisory Committee 
Report on Belt Air and has placed the issue of using belt air to 
ventilate the working face on the rulemaking agenda for development of 
a proposed rule. Thus, "belt air" is not addressed in this 
rulemaking.
    MSHA has also received comments and recommendations on a number of 
other issues that are outside the scope of this rulemaking. For 
example, much of the extensive testimony directed toward the use of 
atmospheric monitoring systems was beyond the issues dealt with in this 
rulemaking. Also, recommendations for the use of transparent or 
translucent material for check curtains exceed the scope of this 
rulemaking. The final rule, therefore, does not include these 
recommendations.
    Commenters to the proposal frequently included a discussion of 
various accident reports, most written by MSHA. In addition, there were 
discussions of other documents related to specific incidents or mines, 
such as MSHA Internal Review Reports or specific mine plans. In some 
cases, the documents were submitted for inclusion in the record. In 
other cases, the documents were merely referenced.
    MSHA is independently aware of the extensive history of ventilation 
related explosions, and has considered this information. Where 
appropriate, this information is discussed in the section-by-section 
analysis in the preamble of this rule. MSHA is aware that accidents can 
result from or be contributed to by the violation of one or more of the 
existing standards. In that context, MSHA has found that the solution 
is not necessarily to promulgate another standard. (The offender may be 
as likely to ignore it as well.) Instead, for demonstrated 
noncompliance with existing standards, the solution is often found in 
increased emphasis, training, or enforcement, rather than in the 
promulgation of additional rules.
    Several sections of the final rule deal with requirements for 
sections and areas where mechanized mining equipment is being installed 
or removed. These provisions, which were included in the existing 
standard published in May 1992, were reproposed without change for the 
purpose of receiving additional comments from all interested parties. 
One commenter cited the William Station mine explosion as evidence of 
the need for these requirements. Other commenters reiterated an earlier 
objection that the standards were procedurally flawed. MSHA does not 
agree that these provisions are procedurally flawed and notes that each 
of these standards was reproposed and not simply restated as part of 
this rulemaking. Comments relative to the 

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technical merits of an individual standard are addressed in the 
section-by-section portion of this preamble.

Recordkeeping Requirements in the Final Rule

    The final rule revises the recordkeeping requirements for several 
standards. The standards affected are Sec. 75.310, Installation of main 
mine fans; Sec. 75.312, Main mine fan examinations and records; 
Sec. 75.342, Methane monitors; Sec. 75.360, Preshift examination; 
Sec. 75.362, On-shift examination; Sec. 75.363, Hazardous conditions; 
posting, correcting and recording; Sec. 75.364, Weekly examinations; 
and Sec. 75.370, Mine ventilation plan; contents.
    Generally, the final rule requires examiners to record the results 
of methane tests as a percent of methane detected; records must be made 
in a book that is secure and not susceptible to alteration, or 
electronically in such a manner as to be secure and not susceptible to 
alteration; and records must be countersigned by the mine foreman by 
the end of the mine foreman's next regularly scheduled working shift. 
These rules are intended to assure that examination results are 
maintained and made available, and that the appropriate level of mine 
management is made aware of conditions or problems requiring attention. 
The revisions also help assure the integrity of records and enable mine 
management to review the quality of the examinations. MSHA intends the 
term "secure and not susceptible to alteration" when applied to 
electronic storage to mean that the stored record cannot be modified. 
One example of acceptable storage would be a "write once, read many" 
drive.
    Numerous comments were received both supporting and opposing the 
proposed recordkeeping requirements. MSHA reviewed and fully considered 
each of these comments. The proposal would have required that records 
be kept in either state-approved books or in bound books with 
sequential machine-numbered pages. Commenters argued that under the 
existing rule records may be falsified or altered. Commenters also 
stated that accident investigations have demonstrated the need for 
improved records. Other commenters asserted that the proposed 
requirement for bound books with sequential machine-numbered pages adds 
an economic burden for the majority of compliant operators and another 
way should be found, "to foil the very few who are recalcitrant." 
Other commenters stated that since all records currently include dates 
and times, machine-numbered pages are unnecessary.
    Some record books that are currently in use and acceptable under 
the existing standards are vulnerable to misuse or manipulation. For 
example, under the existing rule, records could be kept in a spiral 
notebook or even a loose leaf binder. The final rule addresses this 
issue by requiring that records be made in books that are secure and 
not susceptible to alteration. Examples of books that are considered by 
MSHA to be secure and not susceptible to alteration include, but are 
not limited to, record books that are currently approved by state mine 
safety agencies, and permanently bound books. Examples of books that 
would not be considered books that are secure and not susceptible to 
alteration include loose leaf binders and spiral note books.
    Several commenters advocated the use of computers for the storage 
and retrieval of records. In support of this approach, the commenters 
cited computer records as being highly accurate, requiring less storage 
space and facilitating data retrieval. Other commenters expressed 
concern for the security of records stored electronically, and offered 
examples of breaches of security in record systems at banks and 
national security installations as evidence to support this concern.
    Electronic storage of information and assessing it through 
computers is more and more a common business practice generally and in 
the mining industry. Recognizing this trend, the final rule permits the 
use of electronically stored records provided they are secure and not 
susceptible to alteration, are able to capture the information and 
signatures required, and are accessible to the representative of the 
miners and the representatives of the Secretary. Based on the 
rulemaking record, MSHA believes that electronic records meeting these 
criteria are practical and as reliable as traditional records.
    In the preamble to the proposal, MSHA expressed its intent to 
require a hard copy printout of the information stored electronically 
to be available within 1 hour of a request, and to require backing up 
of the information within 24 hours. Commenters objected to making the 
records available within 1 hour as being too stringent and 
unnecessarily requiring a person to be on duty at all times. MSHA 
agrees that the requirement would be overly burdensome and has not 
included it in the final rule. Similarly, MSHA has not included a 
specific requirement for backing up the computer data. The final rule 
requires that the records be secure. This encompasses backing up the 
data as appropriate to the conditions and electronic storage system 
used at the mine. Upon reconsideration, MSHA has concluded that an 
additional specific requirement would be an unnecessary burden and has 
not included it in the rule.
    A variety of comments were received regarding the countersigning of 
certain records by the mine foreman, and the time frame permitted for 
countersigning. The final rule adopts the proposal that the mine 
foreman must countersign the record by the end of the mine foreman's 
next regularly scheduled working shift. The mine foreman is the person 
most responsible for the day-to-day operation of the mine. It is 
essential for the health and safety of the miners that the mine foreman 
be fully aware of the information contained in examination reports so 
as to be able to allocate resources to correct safety problems as they 
develop. Allowing until the end of the mine foreman's next regularly 
scheduled working shift to countersign the reports assures that the 
mine foreman is aware of the results of the examination in sufficient 
time to initiate corrective actions. In response to commenters, the 
final rule allows a mine official equivalent to a mine foreman to 
countersign the records.
    Some commenters suggested that the time for countersigning is 
unnecessarily long, and that the final rule should restore a previous 
requirement that countersigning be completed "promptly." The term 
"promptly" involves a level of ambiguity that is eliminated by 
specifying the time for countersigning records. The record does not 
show that the time set by the final rule would expose miners to safety 
or health risks. Also, hazardous conditions are required to be 
corrected immediately.
    Commenters suggested that the term "mine foreman" be replaced by 
a "certified person responsible for ventilation of the mine or his 
designee." Another commenter suggested that the record could be 
countersigned by the mine foreman or any other mine official 
responsible for the day-to-day operation of the mine. Commenters stated 
that some operations no longer use the terms "mine foreman", "mine 
manager," or "superintendent." To provide for alternative management 
titles, the final rule incorporates the phrase "or equivalent mine 
official."
    Numerous comments were received regarding the requirement of the 
proposal for second level countersigning by the mine superintendent, 
mine manager, or other mine official to whom the mine foreman is 
directly accountable within 2 scheduled 

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production days thereafter. Commenters objecting to the proposal stated 
that higher level management should be able to delegate responsibility, 
noting that often this level of official has more than one mine to 
oversee and may not necessarily be available within the proposed two 
days. One commenter suggested allowing three days for second level 
countersigning in order to recognize that such an official often has 
numerous obligations and to allow for normal absences. Other commenters 
simply recommended that the second level countersigning be deleted.
    Another commenter stated that some states hold the mine foreman 
legally responsible, that the mine foreman should correct hazardous 
conditions immediately and withdraw miners as appropriate, and that the 
second level countersigning would add no measure of safety. One 
commenter noted that in many cases the mine manager or superintendent 
is not a certified individual and long periods may elapse during which 
this person does not go underground. In these instances, the person 
countersigning would have little or no understanding or first hand 
knowledge of the conditions in the mine. Commenters stated that 
countersigning by the mine foreman is adequate notification to the 
operator of any deficiency and that the mine foreman has the necessary 
resources and responsibility to correct any situation noted in the 
records.
    Other commenters supported the proposal noting that second level 
countersigning would provide an additional level of accountability. 
These commenters also suggested that in the event of a major accident, 
the second level countersigning requirement would be important in fully 
assessing the contributing causes.
    MSHA has determined that countersigning by the mine foreman or 
equivalent mine official, as specified in the final rule, provides the 
means necessary to detect and correct developing hazards in a mine. 
Countersigning by the mine foreman assures the necessary notification 
to an official with the knowledge of the day-to-day operation of the 
mine having the authority to maintain the mine in a safe operating 
condition. Agency experience has demonstrated that higher level mine 
officials commonly lack hands-on involvement or in-depth knowledge of 
the specific conditions underground or how the highly detailed 
ventilation rules impact upon those conditions. Therefore, 
countersigning by a mine official at a higher level does not assure any 
additional level of safety and imposes an unnecessary burden.

B. Section-by-Section Discussion

    The following section-by-section portion of the preamble discusses 
each provision affected. The text of the final rule is included at the 
end of the document.

Section 75.301 Definitions

    The final rule revises the definition of return air to permit 
operators to designate certain air courses as return air courses for 
the purpose of ventilating structures, areas or installations that are 
required to be ventilated to return air courses and for ventilating 
seals when the air in the air course will not be used to ventilate 
working places. Thus, an operator wishing to split air off of an intake 
for the purpose of ventilating shops, electrical installations, or for 
other purposes, could designate the air course into which the split is 
directed as a return provided the air in the air course would not be 
used to ventilate working places or other locations, structures, 
installations or areas required to be ventilated with intake air. 
Commenters generally agreed with the change. However, one commenter 
expressed the concern that air currents ventilating electrical 
installations could be coursed to the conveyor belt entry before being 
coursed to a redesignated return air course, and thus not vented 
directly to a return. The commenter expressed the opinion that because 
the air is not vented directly to a return under this scenario, the 
rule would not permit this practice. MSHA does not agree with the 
commenter's interpretation and the final rule, consistent with 
Sec. 75.340, permits this practice.
    MSHA does not anticipate that operators will need to redesignate 
air courses on a routine basis. When questions arise as to the need to 
redesignate an intake as a return, the operator should contact the 
local MSHA office. In order that all interested persons are made aware 
when an air course is redesignated, the final rule requires in 
Sec. 75.372, Mine ventilation map, that such redesignated air courses 
be shown on the mine's ventilation map.

Section 75.310 Installation of Main Mine Fans

    The main mine fans serve a vital role in providing ventilation to 
prevent methane accumulations and possible explosions as well as 
providing miners with a healthful working environment. Section 75.310 
is primarily directed at protecting the main mine fans from fires and 
damage in the event of an underground explosion so that necessary 
ventilation can be maintained. Monitoring of the fans to assure that 
they are operating properly is an element of this protection. The final 
rule for Sec. 75.310 revises paragraphs (a) and (c) of the existing 
rule. The revisions address: (1) automatic signals for fan stoppage, 
(2) pressure recording devices, and (3) main mine fan monitoring 
systems.
    Paragraph (a)(3) of Sec. 75.310, like the proposal, requires each 
main mine fan to be equipped with an automatic device that gives a 
signal at the mine when the fan either slows or stops. The existing 
rule does not specify where the signal is to be given. Commenters 
supported the proposal stating that a signal alarming at a location 
away from the mine site would rely on overland communication lines to 
transmit the signal, with the person receiving the signal then 
notifying the mine. These overland communication lines are subject to 
weather and other potential sources of damage, which could result in a 
disruption of the communication. Other commenters objected to the 
proposal, however, stating that the ability of a mine operator to 
consolidate monitoring of several mines at one single location is a 
very efficient and cost-effective practice and should not be 
arbitrarily prohibited. Further, they stated that there would be 
absolutely no delay in contacting the miners from this central location 
should a fan malfunction occur. For clarity and for increased safety, 
the final rule requires that the signal be given at the mine. MSHA 
believes that in the case of a fan stoppage, this will assure more 
timely notice to miners, and hence, a more effective safety response. 
The requirement that the signal be given at a surface location at the 
mine does not preclude the signal from also being given elsewhere, such 
as at a central office, as long as it is given at the mine.
    Paragraph (a)(3) of Sec. 75.310 requires that a responsible person, 
designated by the operator, shall always be at a surface location at 
the mine where the signal can be seen or heard while anyone is 
underground. In addition, the responsible person must be provided with 
two-way communication with working sections and with other established 
locations where persons are normally assigned to work. Commenters 
supported the proposal stating that the changes provide clarification 
and specificity. Other commenters agreed with the proposed concept of 
two-way communication but felt that the wording, "established 
locations where persons are normally assigned to work" is ambiguous 
and subject to misinterpretation. Some commenters 

[[Page 9768]]
objected to the proposed requirement stating that (1) it is redundant 
of Sec. 75.1600 Communications; (2) properly the subject of a separate 
rulemaking under Sec. 75.1600 or; (3) it is vague, ambiguous, or 
subjective. Section 75.1600 only requires two-way communication between 
the surface and working sections and does not identify that this 
communication must be provided to a location where a person can see or 
hear the fan alarm signal. Commenters suggested that the requirement be 
revised to more specifically quantify locations where persons are 
normally assigned to work. MSHA recognizes that, as proposed, the 
standard might result in misinterpretation and the final rule has been 
reworded to read, "* * * two-way communication with working sections 
and work stations where person(s) are routinely assigned to work for 
the majority of a shift."
    Some, but not all, outby areas where two-way communication would be 
required by the final rule include; shops, attended belt transfer 
points, attended rail car loading points, and attended underground coal 
storage bins and hoppers. It is not intended that this communications 
capability be provided in areas where secondary roof support is being 
installed or where rock dust is being applied, or at unattended 
underground pumps, or in areas such as return air courses, bleeder 
entries and conveyor belt haulageways other than at belt transfer 
points. The requirement that two-way communication be provided to work 
stations where persons are routinely assigned to work for the majority 
of a shift is intended to help assure that these persons receive prompt 
notification of fan stoppages. Because these work stations are off the 
working section, a lack of communication capabilities could result in 
delays in notification and therefore delays in egress from the mine.
    Paragraph (a)(4) of the existing rule requires that main mine fans 
be equipped with a pressure recording device or with a main mine fan 
monitoring system but exempts from this requirement mines permitted to 
shut down main mine fans under Sec. 75.311.
    The final rule eliminates this exemption and requires that all main 
mine fans be equipped with a pressure recording device or a main mine 
fan monitoring device. For mines not currently required to have such a 
device, MSHA has provided for a 1 year phase in period to allow mine 
operators time to effectively plan and implement the necessary changes. 
One commenter suggested that all main mine fans at all mines be 
required to operate continually and further suggested that all main 
mine fans be equipped with pressure recording devices and main mine fan 
monitoring systems. In support of this suggestion, the commenter stated 
that continuous fan pressure recording devices would have a positive 
impact on safety at these operations. Such devices will provide 
necessary information to operators and miners at operations affected by 
this change. MSHA has not included one commenter's suggestion that main 
mine fan monitoring systems be required for all main mine fans. While 
MSHA supports and encourages the use of this advanced technology the 
Agency does not believe that it is appropriate to mandate it for all 
mines because daily fan examinations coupled with pressure recording 
devices have proved to be adequate over the years. Also, MSHA does not 
adopt a suggestion that main mine fans at all mines be required to 
operate continuously.
    Paragraph (a)(4) of the final rule requires that when a pressure 
monitoring device is used in lieu of a pressure recording device, it 
must produce a continuous graph or chart of the fan pressure. A hard 
copy of the continuous graph or chart must be printed at regular 
intervals of not more than 7 days. This provision permits the use of 
relatively recent advances in technology for monitoring main mine fan 
pressure provided a continuous record of the fan pressure is provided. 
In the proposal, MSHA specifically solicited comments as to an 
appropriate polling frequency that would provide a record that is 
substantially continuous. In response to this request, one commenter 
proposed that a polling frequency of two seconds is necessary to take 
full advantage of available technology. This commenter stated that 
continuously means constant or unbroken and that a continuous record 
should require a polling frequency of not greater than 2 seconds. 
Another commenter, an instrument manufacturer, suggested that a one 
minute sampling interval is definitely feasible. Main mine fan 
monitoring, when used, is often part of a more comprehensive mine-wide 
atmospheric monitoring system (AMS), and to require that the fan be 
polled every two seconds could delay the polling of other important 
sensors. Additionally, because these pressure monitoring devices are 
intended to be used in lieu of the traditional circular pressure 
recorder they must provide a substantially equivalent record. 
Experience by MSHA engineers following mine explosions and during more 
routine ventilation survey work has shown that the accuracy to which a 
7-day, circular recording chart of the type normally used can be read 
is on the order of several minutes. MSHA would expect that the polling 
frequency for a pressure recording device used in lieu of a pressure 
recorder would be no more than one (1) minute.
    MSHA received a number of comments in response to the proposed 
requirement in paragraph (a)(4) that when a pressure recording device 
other than a circular pressure recorder is used, a hard copy of the 
continuous graph or chart be generated at not more than 7-day 
intervals. Comments ranged from requiring daily printouts to not 
requiring any printout except when requested by an Authorized 
Representative of the Secretary. In response to these comments, the 
final rule retains the requirement for a hard copy of the continuous 
graph or chart be generated at not more than 7-day intervals. In light 
of MSHA's stated position to permit records of examinations to be 
stored electronically, the final rule permits the record of main mine 
fan pressure to be stored electronically provided the record is secure 
and not susceptible to alteration.
    Paragraph (c) of Sec. 75.310 specifies requirements for main mine 
fan monitoring systems if used under Sec. 75.312. Commenters suggested 
that the requirements were repetitive, confusing, and would discourage 
mine operators from using monitoring systems which could provide more 
protection. MSHA believes that the requirements in paragraph (c) are 
necessary to effectively monitor a fan, particularly when these systems 
are used in lieu of daily fan examinations.
    Paragraph (c)(3) of Sec. 75.310 of the proposal would have required 
that main mine fan monitoring systems provide, on demand, a printout of 
the monitored parameters, including the mine ventilating pressure. 
Several commenters objected to the requirement that a printout be 
provided "on demand." As interpreted by these commenters, this 
standard would require that the operator provide a printout at any time 
it is requested. As explained in the preamble to the proposal, "* * * 
the monitoring system would be required to have the capability of 
providing (emphasis added), on demand, a printout of the information 
being monitored. This capability is intended to facilitate the review 
of the information by mine management required in Sec. 75.312(b)." The 
commenters misinterpreted the purpose for the standard. MSHA 
recognizes, 

[[Page 9769]]
however, the merits of being able to obtain a printout within a 
reasonable period of time. Therefore, the final rule requires that a 
main mine fan monitoring system used to satisfy the requirements of 
Sec. 75.312 provide a printout of the monitored parameters, including 
the mine ventilating pressure, within a reasonable period, not to 
exceed the end of the next scheduled shift during which miners are 
underground.
    Paragraph (c)(5) of Sec. 75.310 requires that two-way communication 
be provided between a surface location at the mine where the signals 
from the fan monitoring system can be seen or heard and working 
sections and other established locations where persons are normally 
assigned to work for the majority of the shift. Except for minor 
editorial changes, this requirement is the same as the proposal. 
Comments on this proposal were the same as comments on proposed 
paragraph (a)(3). Several commenters supported the proposal stating 
that the changes provide clarification and specificity. Other 
commenters agreed with the proposed concept of two-way communication 
but felt that the wording, "established locations where persons are 
normally assigned to work" is ambiguous and subject to 
misinterpretation. Some commenters objected to the proposed requirement 
stating that (1) it is redundant of Sec. 75.1600 Communications; (2) 
properly the subject of a separate rulemaking under Sec. 75.1600 or; 
(3) it is vague, ambiguous, or subjective. Section 75.1600 only 
requires two-way communication between the surface and working sections 
and does not identify that this communication must be provided to a 
location where a person can see or hear the fan alarm signal. 
Commenters suggested that the requirement be revised to more 
specifically quantify locations where persons are normally assigned to 
work. MSHA recognizes that, as proposed, the standard might result in 
misinterpretation and the final rule has reworded the proposal to read, 
"* * * two-way communication with working sections and work stations 
where person(s) are routinely assigned to work for the majority of a 
shift."
    Some, but not all, outby areas where two-way communication would be 
required by the final rule include; shops, attended belt transfer 
points, attended rail car loading points, and attended underground coal 
storage bins and hoppers. It is not intended that this communications 
capability be provided in areas where secondary roof support is being 
installed or where rock dust is being applied, or at unattended 
underground pumps, or in areas such as return air courses, bleeder 
entries and conveyor belt haulageways other than at belt transfer 
points. The requirement that two-way communication be provided to work 
stations where persons are routinely assigned to work for the majority 
of a shift is intended to help assure that these persons receive prompt 
notification of fan stoppages or other problems with the fan that might 
require withdrawal of miners. Because these work stations are off the 
working section, a lack of communication capabilities could result in 
delays in notification and therefore delays in egress from the mine.

Section 75.311 Main Mine Fan Operation

    The main mine fan provides the pressure that causes air to move 
through the mine to dilute and carry away explosive and toxic gases, 
dusts and fumes. As such it is the most important part of the 
ventilation system. Section 75.311 requires fans to be continuously 
operated to provide constant ventilation to underground areas and 
specifies precautions for planned fan stoppages. It also addresses the 
repair of main mine fans, monitoring of fan signal devices on the 
surface, and protection against fires around fans and intake air 
openings.
    The final rule revises paragraph (d) of Sec. 75.311, which 
addresses the notification of mine officials of any unusual variance in 
mine ventilation pressure and requires the prompt repair of electrical 
or mechanical deficiencies. The final rule requires immediate 
notification and the prompt institution of corrective action or 
repairs.
    Commenters suggested deletion of the word "unusual" maintaining 
that this term makes the requirement vague and subject to different 
interpretations. These commenters suggested substituting the phrase, 
"that could materially affect the safety and health of persons in the 
mine" to describe the type of pressure variance that would require 
action. In making this recommendation, the commenters cited similar 
language in existing Sec. 75.324(a)(1) that, according to the 
commenters, is understood throughout the coal mining community. Section 
75.324(a)(1) concerns alterations of the main ventilation air current 
or any split of the main air current. The final rule does not adopt 
this recommendation. Minor fluctuations in fan operating pressure are 
normal; however, unusual changes can be indications of changes in fan 
operation or changes underground, such as roof falls or loss of 
ventilation controls, that require prompt attention and corrective 
action. In addition, MSHA has 25 years of experience with the phrase 
"unusual variances in mine ventilation pressure" and is unaware of 
significant difficulties with this terminology.
    Commenters questioned what constitutes an "electrical or 
mechanical deficiency" for the purposes of Sec. 75.311. The purpose of 
the standard is to assure that a problem with main mine fans is 
corrected promptly and that the proper persons are notified that the 
problem exists. The types of electrical or mechanical deficiencies 
requiring action under paragraph (d) are those that can interfere with 
mine ventilation. In addition, MSHA has 25 years of experience with the 
phrase "electrical and mechanical deficiencies" and is, again, 
unaware of any significant difficulties with the use of this 
terminology during this time frame.
    Commenters also addressed the proposal that the "mine 
superintendent, assistant mine superintendent, or mine foreman be 
notified immediately when an unusual variance in mine ventilation 
pressure is observed, or when an electrical or mechanical deficiency in 
a main mine fan is detected. The final rule does not retain the mine 
superintendent or the assistant mine superintendent as mine officials 
to be notified. Commenters stated that this provision provides a 
measure of safety to the miners by requiring that specific mine 
managers be notified of possible main mine fan problems, while the 
existing standard specifies that such a situation must be investigated. 
Other commenters, however, suggested that the persons identified for 
notification under the proposal may not be the most qualified to handle 
the problem. They also indicated that the notification requirement 
could unnecessarily delay appropriate action by other responsible 
persons. The commenters further stated that the mine superintendent or 
assistant mine superintendent may not be at the mine and that a 
certified person would be in charge who should be permitted to take the 
appropriate action. The proposed requirement that certain mine managers 
be notified immediately was not intended to require that these 
individuals personally take the necessary actions to respond to the 
problem with the main mine fan. Neither was it intended that they be 
notified of such a problem, to the exclusion of all others. The 
objective of the rule is to assure that the appropriate actions are 
taken as soon as possible. Additionally, notification of specified mine 
officials is intended to assure that those persons who are responsible 
for the mine are aware of the problem. The 

[[Page 9770]]
final rule, therefore, retains the requirement that certain mine 
managers be notified of any unusual variance in the mine ventilation 
pressure or if an electrical or mechanical deficiency of a main mine 
fan is detected.
    The final rule does, however, delete reference to notification of 
the mine superintendent or assistant mine superintendent. As discussed 
in relation to the countersigning of records, the mine superintendent 
is quite often not a certified person and is only periodically present 
at the mine. In addition, consistent with other sections of the final 
rule and recognizing that the term mine foreman is not used at some 
mines, the final rule requires that if an unusual variance in the mine 
ventilation pressure is observed, or if an electrical or mechanical 
deficiency of a main mine fan is detected, the mine foreman or 
equivalent mine official, or in the absence of the mine foreman or deficiency
of a main mine fan is detected, the mine foreman or 
equivalent mine official, or in the absence of the mine foreman or 
equivalent mine official, a designated certified person acting for the 
mine foreman or equivalent mine official shall be notified immediately. 
As with the proposal, the final rule requires that appropriate action 
or repairs shall be instituted promptly. It is not intended that the 
appropriate action or repairs be delayed until the mine foreman or 
equivalent mine official is notified.
    During a series of informational meetings held by MSHA following 
publication of the existing rule, questions arose concerning the 
operation of back-up fans. For informational purposes, the preamble to 
the proposal included a detailed discussion of questions about the 
operation of back-up fans under the ventilation regulations and 
solicited comments. MSHA did not propose any rule changes, nor does the 
final rule contain specific provisions for back-up fans. When a back-up 
fan operates in place of the main mine fan, the back-up fan is 
considered to be a main mine fan and all subpart D requirements for 
main mine fans are applicable.

Section 75.312 Main Mine Fan Examinations and Records

    Proper operation of main mine fans is critical to mine ventilation 
and the prevention of methane accumulations and possibly methane 
explosions. Recognizing the importance of the main mine fan, 
Sec. 75.312 requires that each main mine fan be examined at least once 
each day that the fan operates unless the fan is continuously monitored 
with a main mine fan monitoring system. Through daily examinations or 
continuous monitoring of critical parameters, the operator can 
determine if problems with the fan are developing and correct these 
problems before ventilation is affected.
    The final rule removes existing paragraph (g)(2), revises existing 
paragraphs (a), (b)(1), (c), (d), (g)(1) and (h), redesignates existing 
paragraph (f) as (f)(1), and adds new paragraphs (f)(2) and (g)(2). 
Paragraph (a) of the final rule, like the existing rule, requires daily 
examination of main mine fans unless a fan monitoring system is used. 
In addition, paragraph (a) specifies that an examination of the main 
mine fan is not required on days when no person goes underground. An 
examination of the fan, however, is required prior to anyone entering 
the mine. The purpose of this examination, as stated in paragraph (a), 
is to assure the electrical and mechanical reliability of the fan.
    When a fan monitoring system is used, the final rule requires a 
daily review of the data from the monitoring system to be made, except 
on days when no person goes underground. A review of the data from the 
monitoring system must be completed, however, prior to anyone entering 
the mine.
    Fan examinations or review of fan monitoring system data are 
required to be performed by a trained person designated by the 
operator.
    Commenters questioned the use of the term "assure" in paragraph 
(a) when referring to the electrical and mechanical reliability of main 
mine fans. MSHA uses the term "assure" in this context as defined in 
Webster's Third New International Dictionary, Unabridged, 1993 edition, 
to mean, "to make safe, to give confidence to." The sense of this 
definition is consistent with the intended purpose of the examination. 
The term does not mean to "guarantee" safety, as suggested by one 
commenter.
    Commenters suggested that the final rule require the examination of 
main mine fans for proper operation be conducted by an individual 
trained as part of the mine operator's training plan required by MSHA's 
comprehensive training regulation in part 48 of 30 CFR. Other 
commenters understood the proposal to require training of fan examiners 
under part 48, and objected to such a requirement. These commenters 
suggested that the person conducting the fan examination be one who has 
received training through experience or has been trained by an 
experienced person, or by the fan manufacturer. The final rule does not 
require fan examiners to be trained as part of the operator's part 48 
training plan. Instead, the final rule specifies that fan examiners 
must be trained sufficiently to have the skill and knowledge to 
ascertain whether the fan is in proper working order, mechanically and 
electrically.
    Paragraph (a) requires a daily physical examination of the main 
mine fan, unless a fan monitoring system is used. If a fan monitoring 
system is used, paragraph (b) requires a weekly physical examination of 
the main mine fan, a weekly test of the monitoring system, and a daily 
review of the main mine fan monitoring data. Commenters suggested that 
even if a main mine fan is equipped with a monitoring system, the fan 
should still be subject to daily physical examinations because a fan 
monitoring system is not capable of disclosing all conditions that a 
physical inspection could disclose. The final rule does not adopt this 
suggestion. A weekly physical examination of the fan and a test of the 
monitoring system coupled with a daily review of the monitoring data 
provides reasonable assurance that a mine fan is operating reliably. 
Commenters suggested that the proposed requirement of paragraph (b)(1) 
requiring a daily review of main mine fan monitoring system data is 
unnecessary and redundant. These commenters suggested that the system 
need only be capable of producing a printout because the systems would 
automatically alarm anytime an electrical or mechanical deficiency 
exists. Requiring a daily review of the monitoring system data, 
according to these commenters, could discourage the use of improved 
technology. Other commenters noted that operators currently using fan 
monitoring systems conduct a daily review of the data at the present 
time and that the requirements to review the data would provide an 
additional measure of safety for the miners. MSHA believes that a daily 
review of data from fan monitoring systems is needed to assure that 
mine management is made aware of any operational changes or trends in 
monitored parameters. Main mine fans provide the source for mine 
ventilation and, therefore, are critical to miners' safety. As 
discussed earlier, these daily reviews of data are designed to 
complement the physical examinations of the fan.
    The final rule adopts the requirements of proposed paragraphs 
(b)(1)(ii) (A) and (B) and requires that when a fan monitoring system 
is used as provided under paragraph (a), a trained person designated by 
the operator must test the system for proper operation at least every 7 
days. Commenters objected that it is redundant because a fan monitoring 
system is capable of monitoring itself and can automatically provide a 
warning when a fan malfunction occurs. These commenters also stated 
that if the 

[[Page 9771]]
system is continuously operated, the system is self-tested for proper 
operation several times a minute and that the 7-day test is 
unnecessary. The commenters suggested that the 7-day test only be 
conducted if the fan monitoring system is not continuously operated. 
For continuously operating fans an examination of the fan should more 
appropriately be conducted monthly, according to these commenters. 
Requiring more frequent checks the commenters maintain would discourage 
the use of fan monitoring systems.
    The final rule does not adopt these suggestions. While MSHA 
encourages the use of fan monitoring systems, excessive reliance on the 
self-monitoring features of these systems is incompatible with the 
importance of reliable operation of main mine fans. MSHA does not 
anticipate that the final rules for examination requirements will 
discourage the use of fan monitoring systems. Main mine fans without a 
monitoring system are required to be examined daily, while fans with 
monitoring systems are required to be examined every seven days.
    Paragraphs (c) and (d) of Sec. 75.312 of the final rule continue in 
effect the requirements that tests of the automatic fan signal device 
and automatic closing doors, when these doors are required, be 
conducted at intervals not to exceed 31 days. The specified means of 
testing these devices and doors is by stopping the fan. The proposal 
would have permitted an alternative test not involving stopping the fan 
if the alternative method provided the same level of assurance that the 
signal device or door would function as intended during fan stoppages. 
Two commenters favored the proposal and suggested that there is no need 
to approve alternate means of testing fan signal devices in the mine 
ventilation plan. These commenters expressed the opinion that each 
authorized representative should be capable of ascertaining the 
validity of the alternative method. The commenters did not make a 
similar suggestion relative to the alternative means provision proposed 
in paragraph (d) for automatic closing doors. Another commenter opposed 
the use of alternative tests stating that it would be premature to 
adopt a provision for an alternative test to stopping the fan when such 
a test has not as yet been developed. MSHA has reconsidered the 
proposal and the final rule continues to require that the tests of fan 
signal devices and automatic closing doors be conducted by stopping the 
fan. Should an operator develop an alternative method that provides the 
same level of protection as stopping the fan, the petition for 
modification process is available for an operator to obtain approval.
    Paragraphs (c) and (d) permit underground power to remain energized 
during fan signal and automatic closing door testing, notwithstanding 
the requirements of Sec. 75.311. If the fan is not restarted within 15 
minutes, the final rule requires that underground power be deenergized 
and no one is permitted to enter any underground portion of the mine 
until the fan is restarted and an examination is conducted. 
Additionally, paragraphs (c) and (d) require that only persons 
necessary to evaluate the effect of the fan stoppage or restart, or to 
perform maintenance or repair work that cannot otherwise be done while 
the fan is operating, are permitted underground.
    Some commenters objected to limiting the persons who can be 
underground during fan signal and closing door tests. Other commenters 
objected to anyone being permitted underground during the stoppage of a 
fan to conduct the required tests. These commenters expressed the 
opinion that all necessary work can be performed with the fan operating 
and therefore, when a fan is shut down to test the fan signal device or 
the automatic closing doors no one should be underground.
    Some work, such as working immediately inby a blowing fan, could 
place workers at risk by exposing them to extreme temperatures, effects 
of the high velocity air stream, or excessive noise levels when the fan 
is operating. In addition, repair work within a shaft can more safely 
be done when a fan is stopped. The rule, therefore, retains the 
exception that permits persons underground during intentional fan 
stoppages to evaluate the effect of the fan stoppage or restart, or to 
perform maintenance or repair work that cannot otherwise be done while 
the fan is operating.
    Paragraphs (c) and (d) of the final rule are reworded to clarify 
that during the required tests, power circuits may remain energized 
only if no person is underground. Therefore, if an operator elects to 
evaluate the effect of the fan stoppage or restart, or to perform 
maintenance or repair work that cannot otherwise be done while the fan 
is operating, simultaneous with the tests required, power circuits must 
be deenergized in accordance with Sec. 75.311(b)(3). Additionally, in 
accordance with Sec. 75.311(b)(2), all mechanized equipment must be 
shut off.
    Paragraph (f)(1) of the final rule retains the longstanding 
requirement that the person performing main mine fan examinations 
certify by initials and date at the fan or another location specified 
by the operator that the examinations were made. Each certification is 
required to identify the main mine fan that was examined. When daily 
fan examinations are conducted, daily certification is required. When a 
main mine fan monitoring system is used and fan examinations are 
conducted at 7 day intervals, certification is required each time the 
fan is examined.
    One commenter offered suggested wording that would eliminate the 
option of certifying that the examination was completed at a location 
other than the fan being examined. This suggestion has not been adopted 
and the final rule retains the flexibility for certifications to be 
made away from the fan.
    Paragraph (f)(2) of the final rule requires that when a main mine 
fan monitoring system is used, a daily printout of the system's data 
must be certified to indicate that the daily review was completed. 
While some commenters generally agreed with this requirement other 
commenters suggested that an alternative should be provided for systems 
which are continuously operated and supervised. In such cases, the 
commenters suggested that immediate notification of the mine foreman 
when a deficiency arises would be appropriate, together with 
maintaining the internal records of data gathered by the systems for 
one year.
    The suggested alternative is not included in the final rule. MSHA 
believes that documentation that monitoring system data is being 
reviewed is necessary to provide reasonable assurance that mine 
management is aware, on a timely basis, of the operating condition of 
the fan being monitored. However, to reduce the burden of this 
requirement, the final rule in paragraph (f)(2) does permit the 
electronic certification of the review of the data generated by a fan 
monitoring system. As with electronically kept records, the rule would 
require that the electronic certification include handwritten initials 
and dates. A discussion of comments concerning the use of computers to 
maintain records can be found in the General Discussion of this 
preamble.
    Paragraph (g)(1) of Sec. 75.312 requires that by the end of the 
shift on which the examination is made, persons making main mine fan 
examinations must record all uncorrected defects found during the 
examination that may affect the operation of the fan. The rule also 
specifies that records be maintained in a book that is secure and not 
susceptible 

[[Page 9772]]
to alteration, or electronically in such a manner as to be secure and 
not susceptible to alteration. The proposal would have required all 
defects found during the main mine fan examination that may affect the 
operation of the fan to be recorded whether corrected or uncorrected.
    Some commenters objected to recording defects that "may" affect 
the operation of the main mine fan, and suggested only defects that do 
affect the operation of the main mine fan and that are not corrected by 
the end of the shift, need to be recorded.
    Some commenters asserted that a record of "all" defects should be 
required in order to identify recurring problems that may lead to 
bigger problems. These commenters interpreted the proposal to require 
such a record. The final rule is intended to address problems found 
during fan examinations that may indicate more serious defects and 
ultimately lead to a fan failure and that cannot be corrected by the 
end of the shift. The objective is to record defects of a nature and 
seriousness that could result in a fan failure, but not to record 
defects that are so minor that it would be unreasonable to expect fan 
failure to result. Another commenter stated that recording all defects 
that may affect fan operation would result in excessive paperwork of 
little value. This commenter also suggested that if mine ventilation 
does become ineffective, the workers are to be withdrawn from the mine. 
MSHA is sensitive to concerns about recordkeeping. Therefore, the final 
rule requires that all uncorrected defects which are found during the 
examination that may affect fan operation be recorded. In this manner, 
miners on the oncoming shift are aware of problems with the fan that 
potentially could impact underground ventilation.
    Commenters supported the use of electronic media as a substitute 
for specific types of record books. Commenters pointed out that almost 
all such systems incorporate recordkeeping functions and that 
significant variances from the norm are easily noted. They concluded 
that the computer monitoring systems provide superior protection for 
the miners. The final rule permits, in paragraph (g)(1), the use of 
electronically stored records for main mine fan examinations provided 
the records are secure, are able to capture the information and 
signatures required, and are accessible to the representative of the 
miners and the representatives of the Secretary.
    As with other records required by this rule, paragraphs (g)(2) and 
(g)(3) require that records required by Sec. 75.312 must be made in 
books that are secure and not susceptible to alteration, or 
electronically in such a manner as to be secure and not susceptible to 
alteration. A detailed discussion of record books and the use of 
computers to maintain records can be found in the General Discussion of 
this preamble.
    Paragraph (g)(2) of the existing rule requires that at mines 
permitted to shut down main mine fans under Sec. 75.311, if a pressure 
recording device is not used, a record shall be made, in a book 
maintained for that purpose, of the time and fan pressure immediately 
before the fan is stopped, and after the fan is restarted and the fan 
pressure stabilizes. The final rule does not retain this requirement in 
light of the new requirement of Sec. 75.310(a)(4) that all main mine 
fans be provided with a pressure recording device or an option of the 
use of a fan monitoring system. This new requirement eliminates the 
need for an additional record of the time and fan pressure made 
immediately before the fan is stopped and after the fan is restarted 
and the fan pressure stabilizes. This information is obtained from the 
pressure recording chart, which records the pressure continuously and 
automatically, thus maintaining the protection afforded the miners.
    Paragraph (h) of the final rule requires that the records required 
by Sec. 75.312 be maintained at a surface location at the mine for one 
year and be made available for inspection by authorized representatives 
of the Secretary and the representative of miners. Comments were 
generally favorable on this proposal. A discussion of comments 
concerning the use of computers to maintain records can be found in the 
General Discussion of this preamble.
    As with the other provisions of the final rule allowing electronic 
certification or recordkeeping, sufficient protections have been 
included so that there is no reduction in protection from the existing 
standards.

Section 75.313 Main Mine Fan Stoppage With Persons Underground

    Section 75.313 was stayed by MSHA as explained in the introductory 
section of this preamble. Generally, this standard is concerned with 
protecting miners from the danger introduced when the main mine fan 
stops, such as when there is a loss of power. Under these 
circumstances, mine ventilation is interrupted, permitting gases such 
as methane to accumulate. These conditions can lead to an explosion 
ignited by electric circuits or the operation of equipment.
    Paragraph (a)(3) of the final rule requires that if a main mine fan 
stops, everyone shall be withdrawn from the working sections and from 
areas where mechanized mining equipment is being installed or removed. 
The language of the final rule is identical to the wording of stayed 
Sec. 75.313 (a)(3). An in-depth discussion of provisions concerning the 
installation and removal of mechanized mining equipment is presented in 
the General Discussion section of this preamble.
    The final rule revises paragraphs (c)(2), (c)(3), (d)(1)(i) and, 
(d)(1)(ii) of the stayed standard. Paragraphs (c)(2) and (c)(3) require 
that when a main mine fan stops with persons underground, the 
underground electric power circuits shall be deenergized and mechanized 
equipment shall be shut off. These rules further recognize an exception 
to facilitate miners' evacuation from the mine. The exception 
temporarily permits some circuits to remain energized and some 
mechanized equipment to not be shut off, provided these circuits and 
mechanized equipment are necessary to withdraw persons from the mine 
and are located in areas where methane is not likely to migrate to or 
accumulate. These circuits must be deenergized and the mechanized 
equipment must be shut off as persons are withdrawn. The final rule 
differs from the stayed standard by limiting the exception permitting 
the use of these circuits or equipment to areas where methane is not 
likely to migrate to or accumulate.
    Paragraph (d)(1)(i) requires that when a fan stoppage lasts for 
more than 15 minutes a preshift-type examination must be conducted 
before persons other than designated examiners, are permitted to enter 
any underground area of the mine. Examiners are permitted to re-enter 
the underground area of the mine from which miners have been withdrawn 
only after the fan has operated for at least 15 minutes unless a longer 
period of time is specified in the mine ventilation plan. Paragraph 
(d)(1)(ii) requires that when a fan stoppage lasts for more than 15 
minutes, underground power circuits are not to be energized and 
nonpermissible mechanized equipment is not to be started until a 
preshift-type examination is conducted, except that designated 
certified examiners may use nonpermissible transportation equipment in 
intake airways to facilitate the conduct of the required examination.
    Some commenters suggested that actions following fan stoppages are 
best handled on a mine-by-mine basis through a plan approval process. 
Along 

[[Page 9773]]
these lines, commenters suggested that the fan stoppage plan approval 
process previously used by MSHA should be used with only minor 
modification to assure that plans do not become standardized, that is, 
model the rule on a past standard with criteria for approval of fan 
stoppage plans. Other commenters, while supporting the concept of fan 
stoppage plans, proposed to tie the submission and approval of such 
plans to total mine ventilation surveys and computer simulations 
conducted by the operator every three months. According to one 
commenter the data provided by these surveys would be used to determine 
the adequacy of a fan stoppage plan.
    The final rule does not adopt the suggestions of the commenters for 
mine fan stoppage plans. One objective in this rulemaking is to reduce 
the need for paperwork, such as plans, where reasonable, uniform 
requirements can be developed. The final rule establishes the general 
requirement that after a fan stoppage lasting more than 15 minutes, 
mine power and equipment is to be shut down. However, experience shows 
that using transportation equipment to facilitate mine evacuation is 
often necessary, provided this is done where gas is not likely to 
accumulate, and circuits are deenergized on the way out of the mine.
    Some commenters suggested that the requirements in paragraphs 
(c)(2) and (c)(3) limiting the use of transportation equipment to areas 
and haulageways ``where methane is not likely to migrate to or 
accumulate'' are inconsistent with certain state laws. As support for 
this assertion, the commenters gave the example of the state of 
Illinois' requirements for evacuating mines following an interruption 
in ventilation, which does not expressly recognize limited use of power 
and equipment to facilitate evacuation. State mine safety laws, 
including Illinois', are similar to the final rule provisions for 
evacuation after a mine fan stoppage. As a general rule, state mine 
safety regulations that are more stringent than MSHA standards are not 
considered to be in conflict with federal regulations, and the more 
stringent safety requirement applies. In this case, if the Illinois 
regulation would not permit temporary use of power and equipment to 
facilitate evacuation, then the state law would not be inconsistent 
with MSHA.
    Several commenters objected to the wording, "where methane is not 
likely to migrate to or accumulate," in paragraphs (c)(2) and (c)(3), 
as being vague. Other commenters stated that the rule's requirement was 
simply good practice that would be heeded by prudent mine managers. 
MSHA agrees that the terms and objectives of the final rule are 
understood in the mining community, and believes that the determination 
of whether methane may migrate from adjacent areas and enter travelways 
and haulageways used by miners during withdrawal should be made on a 
mine-by-mine basis. Therefore, the final rule retains the exception 
that power circuits may remain energized and mechanized equipment may 
be operated only if located in areas where methane is not likely to 
migrate to or accumulate.
    Some commenters stated that history does not support the need for 
the requirements of paragraphs (c)(2) and (c)(3). Mine fan stoppages 
unquestionably result in the existence of unventilated areas and may 
result in highly hazardous methane accumulations. Although there have 
been a limited number of ignitions/explosions directly attributable to 
the operation of transportation equipment during a fan stoppage, the 
true measure of the potential hazard addressed by this standard can be 
seen in the ignitions and explosions that were the result of the 
operation of transportation equipment in unventilated areas. Examples 
of such types of accidents include: The 1972 Itmann No. 3 explosion, in 
which 5 miners died; the 1976 Scotia Mine explosion, in which 15 miners 
died; the 1982 Virginia Pocahontas No. 6 Mine explosion in which 1 
miner was injured; the 1983 McClure No. 1 Mine explosion, in which 7 
miners died; the 1983 Homer City Mine explosion in which a mine 
examiner was killed; the 1983 Greenwich Collieries No. 1 Mine explosion 
in which 3 miners were killed and 4 miners were injured and; the 1993 
explosion at the Buck Mountain No. 2 Mine in which 3 miners were 
injured. Given this history of explosions, it would not be prudent to 
permit electric circuits to remain energized and mechanized equipment 
to be operated in areas or haulageways where methane is likely to 
migrate to or accumulate during a fan stoppage.
    One commenter stated that the in-mine test necessary to determine 
the likelihood of methane migration could only be done with the fan 
stopped. The commenter questioned whether miners would be permitted 
underground during the tests. To the extent the tests require the main 
mine fan to be turned off, persons would be allowed underground to 
evaluate the effect of the fan stoppage or restart.
    Paragraphs (d)(1)(i) and (ii) address safety precautions for 
reentering the mine after ventilation is restored. Key objectives of 
these standards are the protection of the examiners and the safety of 
miners returning to work.
    As proposed, paragraph (d)(1)(i) would have required that when a 
fan stoppage lasts for more than 15 minutes a preshift- type 
examination be conducted covering the requirements of Sec. 75.360(b) 
through (e) before persons, other than designated examiners, enter any 
underground area of the mine. Commenters suggested that to provide the 
level of protection desired, a complete preshift examination, including 
the certification and recordkeeping requirements of Sec. 75.360(f) 
through (g), should be required. Commenters pointed to the need for 
miners reentering evacuated areas to be able to determine if the area 
had been examined and urged that the final rule require the examiner to 
certify by initial, date and time the areas examined.
    MSHA agrees that clear notice to miners about which areas have been 
examined is necessary and consistent with the objectives of the rule. 
The final rule, therefore, adopts the proposal. A record of the 
hazardous conditions found by examiners is required under Sec. 75.363 
of the final rule. This record serves the purpose of providing mine 
management with the information necessary relative to the existence and 
correction of hazardous conditions in the mine. The final rule 
incorporates these requirements by specifying that the scope of the 
examination be conducted as described in Sec. 75.360(b) through (e).
    Under paragraph (d)(1)(i) no one other than designated certified 
examiners would re-enter any underground area of the mine until the 
entire examination is completed. Commenters suggested that paragraph 
(d)(1)(i) be revised to permit partial examinations following fan 
stoppages and restarts under certain conditions. Under this suggested 
approach, the examination would focus on the effectiveness of the 
mine's ventilation system and methane accumulations in travelways, work 
places or other areas where miners will work following the interruption 
of ventilation. One commenter further suggested that an exception to 
this examination be provided for noncoal producing shifts, where 
persons are to work in the shaft, slope, drift, or on the immediate 
shaft or slope bottom area. The commenter suggested the examination 
following a fan stoppage could be limited to this area.
    The final rule does not adopt this approach. Limiting the scope of 
examinations following an interruption in mine ventilation to general 

[[Page 9774]]
ventilation effectiveness and methane accumulation would not focus on 
likely areas of concern. For example, no examination for hazards would 
be required, and no air measurements to determine if the air is moving 
in its proper direction and at its normal volume would be required. As 
to the area of the mine required to be examined, only those places 
where miners will return to work and the route of travel used to reach 
these places must be examined. Thus, the final rule is sufficiently 
flexible to meet the commenter's concerns about non- coal producing 
shifts.
    A question arose during public meetings as to the meaning of the 
term on-coming shift in Sec. 75.360 when applied to Sec. 75.313. For 
the purposes of Sec. 75.313(d)(1)(i) and (ii) the term "persons on the 
on-coming shift" is interpreted as meaning persons on the shift on 
which the fan is restarted. If a fan outage extends from one shift into 
another, a preshift examination as required by Sec. 75.360 must be 
completed before any person, except certified examiners designated to 
conduct the examination, enters the mine.
    Commenters also suggested that the final rule specify a minimum 
time for the fan to run before examiners re-enter the mine so that 
examiners are not unduly exposed to danger. Several commenters observed 
that this is a general practice in the industry.
    MSHA agrees that an important measure of safety is gained by 
allowing the mine fan to run sufficiently long to begin reventilating 
the mine before anyone enters. The final rule, therefore, provides 
designated certified examiners shall enter the underground area of the 
mine from which miners have been withdrawn only after the fan has 
operated for at least 15 minutes unless a longer period of time is 
specified in the approved mine ventilation plan. The 15 minute 
provision will permit re- ventilation of entries in which examiners 
will travel to take place and the examiners will then be traveling into 
the mine in fresh air.
    Proposed paragraph (d)(1)(ii) would have required that when a fan 
stoppage lasts more than 15 minutes underground power circuits are not 
to be energized and nonpermissible equipment is not to be started until 
a preshift-type examination is completed. Commenters objected to the 
proposal for various reasons. One commenter suggested that before power 
is permitted to be energized a complete ventilation survey should be 
required. Other commenters focused on the practical considerations 
involved in conducting examinations and urged that use of 
nonpermissible equipment for the transportation of examiners be 
permitted.
    As revised, paragraph (d)(1)(i) requires that the main fan when 
restarted run for at least 15 minutes so that restoration of mine 
ventilation is underway before anyone enters the mine. Once this is 
accomplished, electrical circuits in shafts and slopes can be energized 
safely as these areas are the first places to be reventilated by fresh 
air. Accordingly, the final rule permits these circuits to be re-
energized after the mine fan has run for at least 15 minutes.
    The final rule also permits examiners to use nonpermissible 
equipment for transportation during the examination. The proposal would 
have prohibited this practice. Some commenters supported the proposed 
prohibition citing two mining accidents involving nonpermissible 
equipment in unventilated areas. Other commenters objected to the 
proposal not to allow the use of nonpermissible equipment to facilitate 
examinations following the restart of a main mine fan. These commenters 
stated that travelways and equipment roadways can be examined and 
tested for the presence of methane, the results of the examination 
called out, and typical nonpermissible transportation equipment placed 
into operation to expedite the examination of the mine.
    After considering all of the comments, MSHA has revised the 
proposal and the final rule permits the use of nonpermissible 
transportation equipment, in intake airways, to facilitate making the 
examinations after an interruption in mine ventilation. Using 
nonpermissible equipment in this fashion has been a demonstrably
 safe practice for many years in the industry. In  addition, the 
requirement of running the fan for 15 minutes before 
reentering the mine, together with keeping the transportation equipment 
in the intake airways where the main ventilating current travels first, 
provides the desired level of safety.
    Under proposed paragraph (d)(2), if ventilation was restored to the 
mine before miners reached the surface, all miners would have been 
required to continue traveling to the surface. As proposed, designated 
certified examiners would have been permitted to remain underground for 
the purpose of beginning the required examination. The final rule does 
not adopt the proposal and retains the language of the existing 
standard.
    While supporting the requirement that miners continue to the 
surface after a fan is restarted, some commenters objected to 
permitting certified persons to remain underground. These commenters 
also took the position that once a fan has been off for more than 15 
minutes, all efforts to restart the fan should be suspended, unless it 
is known that it is safe to restart the fan. Other commenters expressed 
significantly different views on both issues. A number of commenters 
supported restarting the fan as soon as possible because the longer it 
is off, the greater the potential hazard. MSHA concurs with this 
reasoning and the final rule adopts this approach.
    On the issue of requiring the evacuation to continue once it has 
begun until the fan is restarted, even when ventilation is restored, a 
number of commenters objected that such a requirement would result in 
unnecessary delays and may result in additional safety risks. One 
commenter stated that the proposal would not allow for the variables 
that exist from mine to mine. Several commenters suggested that if the 
operator has reason to believe that the time frame of the fan stoppage 
would be less than the travel time or equivalent, the dangers of 
traveling outby into possible pockets of dangerous gas buildup (or 
other travel hazards) far outweigh the dangers of staying on the 
section in intake air back from the face. This would also allow the 
miners to remain on the section and proceed to the working places after 
the fan has restarted and the working places have been examined by a 
certified person.
    MSHA disagrees with this position. In some mines, the time to 
travel from the outside to the working sections can approach 1 hour. 
Following the approach suggested, miners would remain on the section in 
an unventilated mine for up to 1 hour. If at the end of this time 
ventilation is still not restored, it is unclear whether the miners 
then proceed to the surface, traveling through the same area the 
commenter suggested might be hazardous some 45 minutes before.
    The commenters stated further that, Forcing miners to walk out of 
the mine could take hours and unnecessarily delay the restoration of 
ventilation and resumption of operations." While there may be 
instances where the time required to withdraw miners is increased, the 
requirements in paragraphs (c)(2) and (c)(3) have no impact on the 
restoration of ventilation. In fact, MSHA's position is that 
ventilation should be restored as soon as possible following a fan 
stoppage.
    Lastly, a number of commenters suggested that when ventilation is 
restored during evacuation, miners should be permitted to remain where 

[[Page 9775]]
they are and return to working areas after an examination of inby areas 
is completed. These commenters stated that no additional measure of 
safety is gained by requiring miners to continue to the surface if 
ventilation has been restored and the area in which the miners are 
located is free of hazards. MSHA agrees and has retained the language 
of the existing rule. By retaining the existing language, the general 
practice of miners stopping their evacuation and waiting for examiners 
to complete their work will continue. Under this approach, miners 
remain in a safe location while ventilation of the mine is restored. 
They do not return to any area of the mine until it has been determined 
to be safe. The final rule does not prevent mine operators from having 
miners continue to the surface if they so choose. Regardless of whether 
miners remain where they are or continue to the surface, paragraph 
(d)(1)(i) of the final rule requires that the fan operate for at least 
15 minutes before the examination of the areas from which miners have 
withdrawn is examined.

Section 75.320 Air Quality Detectors and Measurement Devices

    Section 75.320 establishes the standards for the devices relied 
upon to test for the presence of methane and other dangerous gases that 
can accumulate in a mine. It generally requires that these devices be 
approved and maintained in permissible and proper operating condition.
    The final rule adds a new paragraph (e). It requires that 
maintenance of instruments required by paragraphs (a) through (d) of 
Sec. 75.320 to detect and measure air quality be done by a trained 
person. The final rule does not include the proposal that before each 
shift care shall be taken to assure the permissible condition of the 
air quality detectors and other measurement devices to be used during 
the shift. MSHA has concluded that this requirement would have been 
redundant with paragraph (a) and is unnecessary. The final rule permits 
an operator to send instruments to a repair facility or to the 
manufacturer for regular servicing. Commenters at the informational 
meetings and in later discussions on the existing rule stated that 
maintenance by trained persons should be specified and that requiring 
only that air quality detectors and other measurement devices be 
maintained in permissible condition would not be sufficient. They 
stated that without a requirement for maintenance to be done by a 
trained person, similar to that which existed in the previous standard, 
a person with less than the necessary understanding of the instrument 
and the permissibility requirements might be assigned the task.
    Several commenters suggested that the requirements of paragraph (e) 
are redundant with general requirements found elsewhere in the 
standards and are unnecessary. Other commenters felt that the current 
performance standard is adequate, but that the meaning of ``assure'' is 
unclear. Still other commenters indicated that the assurance of 
permissibility is properly the responsibility of the user. One 
commenter noted that the instruments are intrinsically safe and that 
the manufacturer's instructions are sufficient. MSHA agrees that the 
general requirement under paragraph (a), together with requiring 
trained persons, is adequate.
    Another commenter suggested that a formal written maintenance 
program be required. Under this suggestion, the program would be 
subject to MSHA approval and would include records of all maintenance 
and calibrations to be made by the end of the shift. This commenter 
also suggested that existing paragraph (a) be revised to provide for 
more frequent calibration by inserting the phrase "* * * or more often 
if necessary * * *." This suggestion has not been adopted since 
compliance with the proper operating and permissibility provisions of 
paragraph (a) would result in more frequent calibration, if necessary. 
MSHA notes that under the previous standard, there was no written 
maintenance program required nor were records required. MSHA believes 
that experience under both the previous and existing standards 
demonstrates that, with the addition of paragraph (e), maintenance and 
calibration is appropriately addressed in the final rule and safety is 
not reduced.
    Several commenters agreed with the proposal for a "trained" 
person to maintain air quality detectors and measurement devices. These 
commenters suggested that the trained person be defined as a person 
designated by the operator who has received training through experience 
in maintenance of the instrument, has been trained by an experienced 
person, or one who has received training by or through the instrument 
manufacturer. MSHA has not adopted this suggestion since the operator 
should have some flexibility as to the mode of training. The 
requirement that the person performing the maintenance must be trained 
is intended to mean that the person be capable of doing the required 
maintenance, not that they receive a specific course of instruction in 
what to do.
    Commenters suggested that maintenance and calibration requirements 
should parallel those proposed under Sec. 75.342 for machine-mounted 
methane monitors. They suggested that, because the detectors and 
monitors perform similar functions, the requirements should be similar. 
The final rule does not adopt this suggestion. The methane monitoring 
instruments under this standard and those governed by Sec. 75.342 are 
subject to different mining conditions. For example, machine-mounted 
monitors must be calibrated and maintained underground, on the 
equipment on which they are installed and on working sections. This 
calibration must also be scheduled within production timetables. 
Handheld detectors and measurement devices, however, are removed from 
the mine and are maintained and calibrated in surface environments. 
Calibration and maintenance of handheld detectors is usually done 
during shifts when the instruments are rotated out of service. Thus 
machine-mounted monitors are calibrated and maintained under more 
strenuous conditions than handheld detectors.
    One commenter suggested that written records of all maintenance and 
calibration should be required. The commenter further suggested that: 
Each operator submit a written maintenance program to MSHA for approval 
and provide a copy to the miner's representative; the written program 
specify training to be provided; records be completed by the person performing
maintenance and be countersigned by the mine foreman within 
24 hours; and that records be maintained for one year and be made 
available to MSHA and the representative of the miners. These 
additional requirements were not included in the proposal and are not 
adopted in the final rule. The requirements contained in the final rule 
adequately address and are appropriately related to the concerns 
relative to maintenance, calibration, permissibility, and the general 
condition of air quality detectors and measurement devices.

Section 75.321 Air Quality

    The primary function of a mine ventilation system is twofold, to 
remove hazardous gases such as methane, and to provide miners with an 
respirable environment in areas where they are required to work or 
travel. As discussed in the introductory section of this preamble, 
Sec. 75.321 of the existing standard was stayed by the United States 
Court of Appeals for the District of Columbia Circuit as it pertains to 
bleeder entries. The final rule, in  [[Page 9776]]
Sec. 75.321, addresses acceptable levels of oxygen and carbon dioxide 
in areas of a mine, including areas of a bleeder entry, where persons 
are required to work or travel.
    Paragraph (a)(1) continues a basic air quality requirement that has 
been in place since 1970 that air in areas where persons work or travel 
contain at least 19.5 percent oxygen and not more than 0.5 percent 
carbon dioxide, and the volume and velocity of the air current in these 
areas be sufficient to dilute, render harmless, and carry away 
flammable, explosive, noxious, and harmful gases, dusts, smoke, and 
fumes. Paragraph (a)(2) applies the same requirement for oxygen, 19.5 
percent, for the air in areas of bleeder entries and worked-out areas 
where persons work or travel. The final rule does not require the 
carbon dioxide level of 0.5 percent to be applied to bleeder entries 
and worked-out areas. Rather paragraph (a)(2) requires that the carbon 
dioxide levels in the air in bleeder entries and worked-out areas where 
persons work or travel not exceed 0.5 percent time-weighted average 
(TWA) and 3.0 percent short-term exposure limit (STEL).
    MSHA interpreted former Sec. 75.301 to require at least 19.5 
percent oxygen and no greater than 0.5 percent carbon dioxide in 
bleeder systems where persons work or travel. It was MSHA's intent that 
existing Sec. 75.321 would necessitate compliance with these levels 
where persons would be exposed in bleeder entries and in worked-out 
areas. However, the application of this provision to bleeders and 
worked-out areas was stayed by the United States Court of Appeals 
pending the outcome of litigation addressing the promulgation of the 
existing rule. MSHA continues to believe that providing necessary air 
quality is essential to protect miners and examiners whenever they work 
or travel in bleeder entries and worked-out areas. Therefore, the final 
rule includes a new provision specifying that the air in bleeder 
entries and worked-out areas where persons work or travel contain at 
least 19.5 percent oxygen, and that carbon dioxide not exceed 0.5 
percent TWA and 3.0 percent STEL. A TWA is the time-weighted average 
concentration for a normal 8-hour workday and a 40-hour workweek. A 
STEL is the maximum time-weighted average concentration to which miners 
can be exposed for a continuous period of up to 15 minutes. Commenters 
noted an error in the preamble to the proposal with respect to the time 
an individual can be exposed to concentrations between the TWA and the 
STEL. MSHA intends to apply TWA and STEL levels in a manner consistent 
with the Air Quality rulemaking. The levels for carbon dioxide in the 
final rule for areas where persons work or travel in bleeder entries 
and worked-out areas are identical to the levels contained in MSHA's 
proposed Air Quality standards for coal and metal and nonmetal mines 
and the 1992 Threshold Limit Values (TLVs) as specified by the American 
Conference of Governmental Industrial Hygienists (ACGIH).
    Some commenters suggested that other changes be included in the 
final rule. First, they recommended that the permissible minimum oxygen 
level for bleeders and worked-out areas be lowered from 19.5 percent to 
18 percent. Second, they suggested that the requirements that apply to 
bleeders and worked-out areas be expanded to include airways associated 
with bleederless mining areas. The rationale given for this second 
recommendation was that the conditions in these airways are similar to 
bleeders. In light of the ongoing Air Quality rulemaking, MSHA is not 
at this time clarifying existing Air Quality standards except those for 
worked-out areas and bleeder entries.
    Commenters for the most part agreed with the change relative to 
carbon dioxide although one commenter indicated that there was no need 
for any standard. Bleeder entries and worked-out areas are required to 
be traveled or evaluated at least weekly. Generally, this is done by a 
person traveling alone who is often required to be in the bleeder 
entries or worked-out areas for an extended period. The purpose of this 
standard is to protect miners, not to regulate air quality where 
persons are not exposed. Therefore, if examinations are performed 
remotely or if persons making the examination can otherwise remain in 
air that meets the requirements of the standard, oxygen and carbon 
dioxide levels at bleeder connectors and bleeder evaluation points 
would not have to meet the concentrations required by the final rule.
    According to the National Institute for Occupational Safety and 
Health (NIOSH) of the U.S. Department of Health and Human Services 
(NIOSH Respirator Decision Logic, May 1987), 19.5 percent oxygen 
provides an adequate amount of oxygen for most work assignments and 
incorporates a safety factor. Also according to NIOSH, the safety 
factor is needed because oxygen-deficient atmospheres offer little 
warning of danger. In the NIOSH publication, "A Guide to Safety in 
Confined Spaces," (page 4), a chart is presented that indicates that 
19.5 percent oxygen is the minimum level for safe entry into an area, 
and that at a level of 16 percent, judgement and breathing are 
impaired. The American National Standards Institute (ANSI), in ANSI 
Z88.2-1992, "American National Standard for Respiratory Protection" 
recognizes that at 16 percent oxygen there is an impairment in the 
ability to think and pay attention, and a reduction in coordination. 
ANSI recognizes that at 19 percent oxygen there are some adverse 
physiological effects.
    The need for regulating the oxygen level where persons work or 
travel in bleeder entries is illustrated by two mining accidents. One 
of these accidents resulted in the death of a mine examiner and the 
second resulted in the near death of two individuals, one of whom was a 
mine examiner. Mine examiners are, through training and experience, the 
individuals best able to identify the hazards associated with 
irrespirable atmospheres. The first accident occurred at the Arclar 
Mine in Equality, Illinois in 1989. Prior to implementation of the 
existing standard, a mine examiner entered a worked-out area that was 
posted with a danger sign and was asphyxiated. Under the existing 
regulation, ventilation or sealing of this area, rather than posting, 
would be required. Because the area was not sealed, the existing 
regulation would require the area to be examined during the weekly 
examination. The final rule would require that the route of travel for 
the examiner contain at least 19.5 percent oxygen. Had the final rule 
been in place when the examiner entered the worked-out area, the 
accident may have been avoided.
    The second accident, although not in a bleeder entry or worked-out 
area, is illustrative of what can happen when individuals, including 
mine examiners, are subjected to oxygen deficient air. In 1983 at the 
Bird No. 3 Mine in Riverside, Pennsylvania, an assistant mine foreman, 
a certified person, entered the mine for the purpose of conducting an 
examination. After traveling approximately 1100 feet, the examiner 
became dizzy, noticed that his flame safety lamp had extinguished and 
withdrew approximately 200 feet where he sat down and apparently became 
unconscious. A second individual upon entering the area in search of 
the examiner also became dizzy but was able to withdraw to a location 
that was not oxygen deficient. When the mine examiner regained 
consciousness, his cap lamp battery had discharged and he traveled in 
total darkness until he encountered a mine rescue team. Air samples 
collected in the area where the mine examiner first became dizzy 

[[Page 9777]]
indicated an oxygen level of about 16.8 percent, while other samples 
collected nearby indicated oxygen concentrations of nearly 20 percent.
    Because mine examiners are required to work or travel in areas 
where oxygen-deficient air could occur without warning, and they 
normally travel and work alone, there must be a requirement that 
provides them the protection necessary for the performance of their 
duties under these conditions. It is important that the level for 
oxygen be established above that identified as resulting in impaired 
judgement because it is essential that individuals traveling in these 
areas remain highly alert. The hazards that can exist in bleeder 
entries and worked-out areas include elevated methane levels, poor 
footing, loose and unstable roof, and water accumulations. For this 
reason, the final rule adopts a minimum level of oxygen of 19.5 percent 
as recommended by NIOSH.
    MSHA is also concerned with the effects of other gases often found 
in bleeder entries. Section 75.322 of the existing regulation limits 
the concentration of noxious or poisonous gases to the current (1971) 
TLV's as adopted and applied by the ACGIH. Section 75.322 specifically 
excludes carbon dioxide since it is covered by Sec. 75.321. However, so 
the mining public will clearly understand the application of the 
regulation, the final rule establishes a separate standard for carbon 
dioxide levels for areas where persons work or travel in bleeder 
entries and worked-out areas. The levels set by the final rule, 0.5 
percent TWA and 3.0 percent STEL, when considered in conjunction with 
the requirements of Sec. 75.322 and the requirement for oxygen, will 
provide persons working or traveling in these areas with a safe and 
healthful working environment. MSHA recognizes that the effects of 
carbon dioxide are both chronic and acute and, therefore, sets both a 
TWA and a STEL. NIOSH, in recommending a standard for carbon dioxide, 
also recognized this and recommended a similar approach. The NIOSH 
recommendation, made in a Criteria Document published in 1976, proposed 
a TWA concentration of 1.0 percent and a ceiling value of 3.0 percent 
not to exceed 10 minutes. In making this recommendation, NIOSH 
recognized that there are additive stress effects of increased carbon 
dioxide concentrations and exercise. As support for this, the NIOSH 
document cites research that showed that healthy, trained subjects 
exposed to 2.8 to 5.2 percent carbon dioxide at maximum exercise levels 
experienced respiratory difficulty, impaired vision, severe headache, 
and mental confusion; three subjects collapsed.
    During rulemaking on the proposed air quality standard, NIOSH 
recommended a 0.5 percent TWA and a 3.0 percent STEL. NIOSH made a 
similar recommendation to the Occupational Safety and Health 
Administration during that Agency's permissible exposure limit 
rulemaking. Given the work environment in bleeder entries and worked-
out areas, as described earlier, MSHA believes that the regulatory 
approach to bleeders and worked-out areas provided by the final rule is 
necessary and appropriate. In addition to examiners, other miners may 
be required to work in the bleeder entries and worked-out areas, 
performing duties such as installing roof support, pumping water, 
recovering materials or adjusting ventilation. The levels established 
in the final rule would provide these miners with the necessary 
protection.

Section 75.323 Actions for Excessive Methane

    Section 75.323 establishes the actions that must be taken when 
methane reaches certain levels. Methane is the most dangerous gas 
encountered by miners working underground. When the level of methane 
reaches 5.0 percent it is explosive. Section 75.323 generally 
establishes action levels below this lower explosive limit to permit 
appropriate actions to be taken by mine operators in order to prevent 
an explosion.
    The final rule adopts the proposal for Sec. 75.323. In doing so, it 
revises paragraphs (b)(1)(ii), (c)(1), and (d)(2)(i) of the existing 
standard. The rule clarifies that corrective actions at specified 
methane levels must be taken "at once" and provides that actions for 
excessive methane include areas where mechanized mining equipment is 
being installed or removed. MSHA believes that final rule Sec. 75.323 
increases the protection afforded by the existing standard.
    Initially, the need for clarification was raised during 
informational meetings and subsequent discussions after publication of 
the existing rule. As discussed below, the final rule retains the 
language of the proposal which is identical to the wording of the 
previous standard.
    Some commenters indicated that delays in remedial actions to reduce 
methane were being experienced at some mines. These commenters 
attributed delays to the deletion of the phrase "at once" in the 
existing standard. These commenters also suggested that the phrase "at 
once" conveys the proper sense of urgency to correct the condition. 
Other commenters stated that the addition of the phrase "at once" 
does nothing to improve health or safety. MSHA has included the phrase 
in the final rule for clarity.
    Methane poses a significant hazard to miners when it is permitted 
to accumulate without corrective action being taken quickly. MSHA has 
always intended that corrective changes be made at once. The final rule 
revises paragraphs (b)(1)(ii), (c)(1) and (d)(2)(i) to require that 
these changes be made "at once," the phrase used in former 
Secs. 75.308 and 75.309.
    Some commenters stated that the proposal, if literally enforced, 
would necessitate changes to be made before the cause or source of the 
increase in methane can be investigated. Other commenters stated that 
approvals must be obtained for many ventilation changes and that some 
changes require extended periods of time to complete. Operators may 
take those actions necessary to abate imminent dangers or hazardous 
conditions, or to safeguard persons and equipment. A part of this 
action would be a determination of the cause of the problem. MSHA knows 
of no case where an operator has been prohibited from a necessary 
correction for a methane problem pending a plan approval. However, in 
cases where intentional changes are made which could materially affect 
the safety and health of miners, approval is required before resumption 
of normal work if the changes affect the information approved in the 
mine ventilation plan. MSHA recognizes that some ventilation changes 
take time to accomplish and interprets the phrase "at once" as 
meaning that the work of making the necessary change to reduce methane 
levels begins immediately.
    One commenter questioned how the phrase "at once" would apply to 
a methane feeder which is encountered despite an appropriate and well 
thought out ventilation change. MSHA recognizes that methane feeders 
may be encountered unexpectedly. As long as a mine operators takes 
action as required by the standard, they will be in compliance.
    One commenter suggested that some MSHA personnel were improperly 
interpreting methane excursions above 1.0 percent to be violations of 
the standard. The commenter seemed to suggest the regulations should 
provide that the actions specified in Sec. 75.323 for excessive methane 
do not apply to concentrations detected on machine-mounted methane 
monitors. Other commenters indicated that the standard requires 
unnecessary ventilation 

[[Page 9778]]
changes in response to instantaneous increases caused by excessive 
methane liberation. MSHA recognizes that instantaneous methane monitor 
readings for machine mounted monitors may occasionally reach or exceed 
1.0 percent. Usually, these are short-lived and the monitor reading 
quickly falls below 1.0 percent, even before the machine operator can 
react. However, consistent monitor readings of 1.0 percent or more 
indicate a problem and should cause appropriate changes and 
adjustments. Repeated short duration increases above 1.0 per cent 
should also be cause for concern and may necessitate changes or 
adjustments to ventilation.
    With respect to paragraphs (b)(1), (b)(2), and (c)(1) some 
commenters stated that the mere presence of methane does not constitute 
a violation of a mandatory health and safety standard. MSHA agrees. In 
this context, one commenter suggested replacing the word "present" 
with "detected." The commenter continued that an operator cannot 
possibly correct a methane problem until it has been detected, that the 
rule should reflect realistic expectations, and that the current term 
"present" is meaningless. MSHA agrees that a methane problem cannot 
be corrected unless it has been detected and that the mere presence of 
methane does not constitute a violation. Only the failure to properly 
respond once being made aware of the presence of methane in excess of 
allowable levels is a violation. The standard requires that an operator 
properly conduct an examination; and if methane over 1.0 percent or 1.5 
percent is found, as applicable, corrective action must be taken at 
once.
    When 1.0 percent or more methane is present in a working place, an 
intake air course, or an area where mechanized mining equipment is 
being installed or removed, paragraph (b)(1)(i) of the final rule 
requires all electrical, diesel, and battery- powered equipment in the 
affected working place, intake air course, or other area, except for 
intrinsically safe AMS, to be deenergized or shut off. Deenergizing or 
shutting off of this equipment protects miners by preventing this 
equipment from providing ignition sources.
    One commenter suggested that non-intrinsically safe AMS equipment 
should be permitted to run under battery power when 1.0 percent or more 
methane is encountered. The commenter stated that the benefit derived 
through the system's operation outweighs the hazard of the non-
intrinsically safe system. The commenter continued that since the 
batteries will deplete quickly, little hazard would result, or in the 
alternative, each battery outstation could be monitored for methane and 
automatically trip at some set methane level. The final rule does not 
include this suggestion. Where excessive methane concentrations 
necessitate that power be deenergized, information from continued 
operation of the non-intrinsically safe system would not outweigh the 
potential ignition hazard. To permit operation of a non- intrinsically 
safe system in areas known to contain excessive levels of methane would 
be a departure from accepted, effective, and long standing safety 
practice.
    Several commenters objected to the requirement in paragraph 
(b)(1)(iii) that prohibits any work in the affected area until the 
methane is reduced to less than 1.0 percent. Commenters questioned 
whether the standard would prohibit an operator from taking steps to 
reduce the methane. The language must be given a reasonable 
interpretation and should be considered in context of the preceding 
requirement in paragraph (ii) that "changes or adjustments shall be 
made at once * * *."
    These requirements are virtually identical to those found in the 
previous standard which was in effect for over 20 years. MSHA is 
unaware of any instance where an operator was prohibited from 
correcting methane problems by such an application of the standard.
    Some commenters suggested adding a phrase to paragraph (b)(1)(iii) 
to read, "No work other than removal of the accumulation shall be 
permitted * * * " Similarly, MSHA believes that the suggested change 
is unnecessary and has not adopted it. MSHA experience indicates that 
the rule is well understood and has been properly applied.
    Other commenters thought that the standard, as proposed, would 
cause hasty, ill-advised changes to be made and would prohibit an 
investigation into the cause or source of the methane problem which 
could result in phased-in corrections. MSHA agrees that operators 
should seek long term solutions and should fully investigate the cause 
or source of methane accumulations. Investigation and long term 
corrections are not prohibited by the rule. However, the final rule 
does require that certain actions be undertaken at once to correct the 
short term or acute safety hazards resulting from accumulations of 
methane.
    If 1.5 percent or more of methane is present in a working place, an 
intake air course, or an area where mechanized mining equipment is 
being installed or removed, paragraph (b)(2) of the final rule requires 
persons to be withdrawn from the affected area. The presence of methane 
in these areas can pose a significant risk to miners and therefore 
their withdrawal from the affected area is essential to their safety. 
Paragraph (b)(2) also requires that all electric power to equipment in 
affected areas be disconnected at the power source. This prevents 
accidental energization of equipment and removes power from cables and 
circuits which may also be ignition sources. No other work is permitted 
in the affected area until the concentration of methane is less than 
1.0 percent. A conforming change is also made to paragraph (b)(2) by 
adding "mechanized" before mining equipment for consistency with 
other provisions of the rule.
    Comments were received which objected to the (b)(2)(ii) requirement 
that except for intrinsically safe AMS, electrically powered equipment 
in the affected area shall be disconnected at the power source. Some 
commenters suggested that this equipment should be simply 
"deenergized." These commenters stated that there was no need to 
disconnect the power source, that this could require belt drives, 
pumps, etc. to be physically disconnected where permanent connections 
have been made, which could result in a major unnecessary operation. 
MSHA has not adopted this suggested revision. MSHA issues numerous 
citations and orders for damaged power cables, trailing cables, and 
splices where the conductors are badly damaged or exposed. Each of 
these citations and orders represents the presence of a potential 
ignition source. Power cables would remain energized under these 
conditions as would be the case if the commenters' suggestion were 
adopted.
    There are several aspects of Sec. 75.323 which were not proposed 
for revision, but for which comments were received. Comments were 
received relative to the 1.0 percent action level in intake air 
courses. Commenters contended that Congress established an immutable 
methane limitation of 0.25 percent in intakes. Commenters stated that 
because Congress had expressly limited intakes passing openings to 
abandoned areas to 0.25 percent methane, that implicitly, all intakes 
were limited to 0.25 percent methane. However, the commenter then 
suggested adopting an intake action level for methane of 0.5 percent. 
MSHA notes that the methane levels were not proposed for revision and 
are not being revised under the final rule. The commenters, however, 
should refer to a discussion of this issue included in the 

[[Page 9779]]
preamble to the existing rule dated May 15, 1992.
    If 1.5 percent or more methane is present in return air, paragraph 
(d)(2)(i) would require changes or adjustments be made "at once" to 
the ventilation system to reduce the concentration of methane. Because 
of the hazards presented by accumulations of methane, MSHA believes 
that changes or adjustments should be made immediately and be made 
independent of the mine ventilation plan in the interest of safety. 
MSHA recognizes that some changes take time to complete. If operators 
begin "at once" to make the necessary changes and adjustments, they 
will be in compliance with the standard.
    MSHA received comments relative to Sec. 75.323 which, although were 
outside the scope of the rulemaking, demonstrate an incorrect 
understanding of the existing rule. The limitations on methane content 
and the associated actions required when excessive methane is 
encountered are important components of a safety program to protect 
underground miners. Therefore, several of these comments will be 
addressed so that the mining community will better understand these 
standards.
    First, one commenter objected to the existing requirements in 
Sec. 75.323(d). The commenter incorrectly stated that paragraph (d) 
permits normal operations with 1.5 percent methane in working places. 
Methane limits in working places and intake air courses is limited by 
Sec. 75.323(b). Paragraph (b) specifies actions if 1.0 percent methane 
is present, and withdrawal if 1.5 percent is present. Similarly, 
Sec. 75.323(c) limits methane between the last working place on a 
working section and where that split of air meets another split of air 
to 1.0 percent and requires withdrawal at 1.5 percent. Paragraph (d) 
modifies the requirement for that portion of the return split outby the 
section loading point and has no effect on methane either in working 
places or between the last working place and the point in the return 
opposite the loading point.
    One commenter indicated a preference for the language used in a 
previous MSHA regulation, Sec. 75.308-1. The previous standard 
restricted the changes or adjustments to increasing the quantity or 
improving the distribution of air in the affected working place to an 
extent sufficient to reduce and maintain the methane to less than 1.0 
percent. The existing rule establishes a performance standard that 
allows for several methods of compliance. One acceptable method of 
compliance is to limit the rate of production of coal to permit the 
existing ventilation system to maintain the level of methane below 1.0 
percent. In all cases, however, increasing the quantity or distribution 
of air continues to be an accepted means of reducing methane levels. No 
safety benefit would be derived from disallowing reduced coal 
extraction rates as a means of maintaining methane levels under 1.0 
percent.
    The final rule retains the language of proposed 
Secs. 75.323(b)(1)(i), 75.323(b)(1)(iii), and 75.323 (b)(2)(i) and 
(b)(2)(ii) which is identical to the wording of the existing standards. 
An in-depth discussion of the reproposal of provisions concerning the 
installation and removal of mechanized mining equipment is presented in 
the General Discussion section of this preamble.

Section 75.324 Intentional Changes in the Ventilation System

    This section addresses the precautions that must be taken when a 
significant change is made to the ventilation system. MSHA did not 
propose any change to existing Sec. 75.324 and is not making any 
revisions in the final rule.
    Questions had been raised concerning the language, "materially 
affect the safety or health of persons in the mine" that appears in 
the existing standard. The phrase is important in that it identifies 
those ventilation changes that require approval of the MSHA district 
manager under Sec. 75.370(c). MSHA regards it as impractical to follow 
a "cookbook" approach to identifying what will or will not require 
approval. Each particular circumstance is to be reviewed by the 
operator on its own merits. To illustrate the Agency's expectations, 
the following is a list of some examples of what MSHA considers 
intentional changes that would materially affect the safety or health 
of miners. These examples are not meant to include all possibilities, 
but are meant to provide some general guidance: adding a new shaft; 
bringing a new fan on line; changing the direction of air in an air 
course; changing the direction of air in a bleeder system; shutting 
down one fan in a multiple fan system; starting a new operating section 
with ventilating quantities redistributed from other sections of the 
mine; changing entries from intakes to returns and vice versa; and any 
change that affects the information required by Sec. 75.371, Mine 
ventilation plan; contents.
    Comments were specifically solicited on issues raised in the 
preamble discussion to the proposal. In response, written comments were 
received from one commenter. These comments were reinforced by several 
speakers at the public hearings. Other commenters indirectly referred 
to Sec. 75.324 and stated that the phrase, "materially affect the 
safety or health of persons in the mine" is accepted and understood by 
the mining community.
    One commenter suggested that the person designated by the operator 
to supervise ventilation changes should be a certified person that is 
knowledgeable of the mine's ventilation system. The results of changes 
to a complex ventilation system are not always easy to predict, and for 
that reason caution must be used when making significant changes to one 
air split or several air splits. The balance of splits can be affected 
and may result in air reversals, dead air spaces, or insufficient air 
flow in critical areas. For this reason, such changes must be evaluated 
by a certified person examining the affected areas to determine that 
the areas are safe before production is resumed. Therefore, the Agency 
believes that it is to be an unnecessary burden to also have 
ventilation changes supervised by a certified person. Thus, the 
suggestion of the commenter has not been adopted in the final rule.
    This commenter also suggested that the provisions of Sec. 75.324 
should apply to all intentional changes which alter the air current in 
any section or area of the mine by 10 percent or more, or by 9,000 cfm 
or more, whichever is less and that such change be considered to affect 
the entire mine. The commenter recommended the miners' representative 
be afforded the right to accompany the certified person to evaluate the 
effects of the ventilation change and that a preshift examination of 
the mine be conducted to assure that the mine is safe before electric 
power is restored.
    The commenter also suggested that a record be maintained of all 
ventilation changes to include the names of all persons involved with 
the change, the date and time of the change, and results and locations 
of air quality and quantity measurements taken both before and after 
the change. The commenter stated that the record should be made in an 
approved book within 24 hours of the change and that the record should 
be signed and countersigned. Finally, the commenter recommended that 
the mine ventilation map should be updated immediately after the 
ventilation change is made and that within 24 hours of the change, the 
updated map should be made available to the miners' representative and 
a copy sent to the district manager. Section 75.370(c) requires that 
any change to the ventilation system that alters the main 

[[Page 9780]]
air current or any split of the main air current in a manner that could 
materially affect the safety or health of the miners, or any change to 
the information required in Sec. 75.371 shall be provided to and 
approved by the district manager before implementation. The final rule 
requires that this information be provided to the miners' 
representative at least 5 days before submittal to the district manager 
(See Sec. 75.370 for full discussion). MSHA believes that this 
provision provides necessary protection for miners.
    One commenter stated that the standard is reactive and that MSHA 
routinely cites mine operators after a methane explosion or ignition. 
MSHA believes that the standard is designed to assure that operators 
are proactive and develop plans that prevent hazardous conditions. The 
Agency anticipates that with the clarification provided through this 
rulemaking, operators will obtain MSHA approval prior to making 
intentional ventilation changes that materially affect the safety and 
health of miners, thereby preventing potentially hazardous conditions. 
When questions arise as to whether an anticipated change requires prior 
approval, MSHA is available to provide guidance as to whether approval 
is necessary.

Section 75.325 Air Quantity

    The quantity of air in cubic feet per minute (cfm) is an important 
measure of underground coal mine ventilation. It is essential for 
miners' health and safety that each working face be ventilated by a 
sufficient quantity of air to dilute, render harmless, and carry away 
flammable and harmful dusts and gases produced during mining. An 
insufficient quantity of air at a working face could permit methane to 
accumulate and lead to an explosion. Section 75.325 generally 
establishes the quantities of air that must be provided and the 
locations underground where these quantities must be provided.
    Section 75.325(d) requires that areas where mechanized mining 
equipment is being installed or removed be ventilated and that the 
minimum quantity of air and the ventilation controls necessary to 
provide these quantities be specified in the approved mine ventilation 
plan. The final rule adds the word "minimum" to the phrase, 
"quantity of air" that appears in the existing standard and the 
proposal. The existing standard was reproposed without change. An in-
depth discussion of the reproposal of provisions concerning the 
installation and removal of mechanized mining equipment is presented in 
the General Discussion section of this preamble.
    Only a few comments were received that were specific to paragraph 
(d). One commenter discussing Sec. 75.371(r) suggested that the 
quantity of air required by Sec. 75.325(d) to be specified in the plan 
should represent the "minimum" quantity to be provided and that the 
location specified should be identified as typical so as to give the 
mine the flexibility to adapt to conditions. This comment is consistent 
with MSHA's intent for the proposal and helps to clarify it. Therefore, 
the word "minimum" has been inserted into the final rule in both 
Sec. 75.371(r) and paragraph (d) of Sec. 75.325. Obviously, mine 
operators can have air quantities which exceed the minimum specified in 
the mine ventilation plan. MSHA agrees conceptually with a comment that 
the ventilation scheme shown in the plan should be representative of 
the method of ventilation to be used. However, MSHA does not adopt this 
comment because the plan must also be specific enough so that the 
operator, the miners, the representative of miners, and MSHA are 
assured that the areas are being adequately ventilated.
    Other commenters suggested that the total quantity of air to be 
delivered to a longwall needs to be specified in the mine ventilation 
plan. In support of the suggestion the commenter stated that the 
inclusion of the word "total" recognizes that some mines may use belt 
air at the set up or tear down phase while some intake air may be 
diverted to ventilate bleeders, battery chargers or compressors and, 
therefore, the total quantity of air being delivered to the longwall 
face should be the figure with which MSHA is concerned. The commenter 
stated further that the recommendation recognizes that conditions vary 
greatly from mine to mine, coal seam to coal seam, even from one 
longwall panel to the next panel of the same mine. The commenter added 
that while a specified amount of air can be delivered to a recovery 
face, and pressure can be placed on the gob, it is impossible to 
guarantee a specified volume or velocity of air at the recovery point.
    MSHA agrees that the total air quantity provided to a recovery face 
is of importance; however, the distribution of this air is also 
important. The volume of air being delivered to the longwall face 
during equipment removal is important because of the types of 
activities that occur (e.g. cutting and welding and the operation in 
some cases of considerable numbers of diesel powered vehicles) and the 
fact that it is along the face that the majority of miners work and 
where an ignition hazard exists. It is important to know exactly how 
areas where mechanized equipment is being installed or removed will be 
ventilated. Therefore, this suggestion has not been included and the 
rule.
    Commenters were concerned about the ventilation of a longwall face 
prior to the first gob fall. This type of concern should be handled 
through the mine ventilation plan. Paragraph (d) only deals with areas 
were mechanized mining equipment is being installed or removed and not 
where mining is in progress.

Section 75.330 Face Ventilation Control Devices

    The final rule adds a new paragraph (c) adopting the proposal 
language. The new paragraph (c) requires that when line brattice or any 
other face ventilation control device is damaged to an extent that 
ventilation of the working face is inadequate, production activities in 
the working place are required to cease until necessary repairs are 
made and adequate ventilation is restored. MSHA notes that before 
issuing a citation for a violation of this provision, an inspector 
would normally be expected to measure the air quantity to determine 
whether adequate ventilation is being maintained.
    Some commenters considered the proposed regulation redundant since 
operators must already maintain minimum air quantities at the face, 
thereby making repairs necessary to maintain the required quantity. 
Face ventilation controls are a critical feature of reliable 
ventilation. As such, maintaining these controls in good condition and 
making repairs necessary to restore ventilation is sound safety 
practice. To do less invites increased risk of a methane ignition and 
elevated respirable dust. Also on a practical level most miners on a 
working section do not have a means of measuring air quantities. 
However, miners can determine when ventilation controls are damaged 
appreciably and are likely to adversely affect the air quantity.
    One commenter indicated that entire working sections might be shut 
down to repair a ventilation control at any one face with no 
corresponding safety benefit. The final rule provides that "production 
activities in the working place shall cease" until adequate 
ventilation is restored. Unless elevated methane levels or some other 
problem existed, the entire section would not be shut down for repair 
of a ventilation control.
    Some commenters asserted that controls may be slightly damaged 
while still maintaining quantities in excess of 

[[Page 9781]]
the requirements at the face. Similarly, commenters worried that 
numerous citations would be issued based solely on the appearance of 
the controls, even though the minimum required face air quantities are 
exceeded. These commenters stated that the only reliable indicator is 
an air measurement.
    MSHA agrees that the only precise indicator of air quantity is a 
measurement. Accordingly, MSHA anticipates that noncompliance decisions 
will be based on air measurements which show "ventilation of the 
working place is inadequate." However, ventilation controls which are 
in poor condition are likely to cue an inspector to conduct an air 
measurement.
    Other commenters generally expressed the view that the requirements 
of Sec. 75.330, even considering the proposed revision, are inadequate 
to fully address the issue of face ventilation. According to these 
commenters, additional requirements are needed, including: proper 
installation and maintenance criteria for face ventilation control 
devices, requirements for providing devices continuously from the last 
open crosscut to the working face, immediate repair of these devices if 
damaged by a fall or otherwise, providing sufficient space between the 
line curtain and the rib and maintaining the area free of obstructions, 
and minimizing leakage while providing installations which permit 
traffic to pass without adversely affecting ventilation. Further, the 
commenters asserted that only cumulatively can the desired result be 
obtained through these requirements and that additional requirements 
would empower individual miners to take corrective actions when needed.
    Each of these suggestions is a desirable ventilation practice which 
MSHA supports. However, the final rule is not intended to set detailed 
standards for the installation of ventilation control devices. Instead, 
the rule addresses minimum requirements for face air quantities and 
requires the face ventilation system used to deliver these quantities 
to be maintained.
    Some commenters indicated a concern about so-called "deep-cut" 
mining wherein continuous miners, by remote control, develop cuts from 
25 to 60 feet inby permanent roof support. Commenters questioned the 
adequacy of face ventilation where ventilation controls may be 30 to 50 
feet from the face. Specifically, questions were raised about: whether 
adequate ventilation actually reaches the face in "deep cuts" to 
dilute methane; whether more frequent air measurements are needed; 
whether methane checks are representative of face concentrations; 
maximum feasible cut depth and ventilation device distance; respirable 
dust in "deep cuts;" proper maintenance of ventilation control 
devices; how ventilation is maintained after the continuous miner is 
withdrawn from the cut; roof bolter ventilation; and differences 
between scrubber systems and sprayfan systems. Another commenter noted 
that historically most roof fall fatalities have occurred within 25 
feet of the face. This commenter asserted that the deep-cut mining 
system helps to resolve this problem and reduce exposure. The commenter 
continues that to prohibit any variation from the 10 foot line curtain 
distance requirement would adversely affect safety of the miners 
working in the area.
    MSHA agrees that each of these issues is important. The appropriate 
vehicle to address these specific concerns is the mine ventilation plan 
required by existing Sec. 75.370. The mine ventilation plan provides 
the necessary latitude to address the diversity of mining conditions 
found throughout the country. Details of each system must be shown in 
the plan and must be specific to the conditions at each mine where such 
a system is employed. Also, MSHA's review and approval of mine plans 
includes an onsite investigation to evaluate the system and to assess 
the adequacy of the specified plan parameters. In addition, inspectors 
routinely evaluate the suitability of the mine ventilation plan during 
regular mine inspections.
    The commenter's concerns about methane checks in "deep cuts" is 
addressed by the final rule Sec. 75.362(d)(2) which requires that 
methane tests be made "at the face." This new requirement will assure 
that measurements are taken at the location where the hazard is most 
likely to occur. Testimony received at the public rulemaking hearings 
indicated that technology exists in the form of extendable probes that 
can be used to take these measurements, without putting miners at 
additional risk from fall of ground.

Section 75.332 Working Sections and Working Places

    Working sections and working places are the areas of a coal mine 
with the greatest amount of activity and the largest concentration of 
workers. They are the location of the greatest number of potential 
ignition sources. They therefore harbor the greatest risk of accidents 
such as methane ignitions and explosions and equipment fires. Section 
75.332 addresses the ways these areas are ventilated to reduce the 
likelihood of an accident on one section impacting another section, 
with deadly consequences. Generally, Sec. 75.332 provides that each of 
these areas must be ventilated with a separate split of fresh air that 
has not been used to ventilate another working area or an area where 
mining has ceased if this area cannot be examined. When ventilated in 
this manner, the products from a fire on one section will not 
contaminate another section and methane in worked-out areas will not be 
carried to working sections by the ventilating air stream.
    The final rule provides that each working section and each area 
where mechanized mining equipment is being installed or removed, shall 
be ventilated by a separate split of intake air directed by overcasts, 
undercasts or other permanent ventilation controls. The final rule 
adopts the language of proposed Sec. 75.332(a)(1), which is identical 
to existing Sec. 75.332(a)(1). An in-depth discussion of the reproposal 
of provisions concerning the installation and removal of mechanized 
mining equipment is presented in the General Discussion section of this 
preamble.
    Several commenters responded to Sec. 75.332(a)(1). Some commenters 
suggested that the standard be revised to permit the installation of 
mechanized mining equipment in either the return or intake air courses 
of working sections provided the air had not been used to ventilate any 
worked-out areas, areas where pillars have been recovered, or bleeder 
systems. The commenters maintained that prohibiting the installation of 
longwall equipment on the same split of air as a developing unit delays 
the installation of a mining system. The commenters further observed 
that this mining equipment consists mainly of steel conveyor sections 
and roof supports that contain a 95 percent water-based hydraulic fluid 
which does not burn. Therefore, according to these commenters, longwall 
mining equipment can safely be installed on the intake side of an 
active mining unit and, with monitoring, in the return air course of an 
active mining unit.
    The safety benefits of using separate splits of air to provide 
ventilation are well established. A primary benefit of such a provision 
is to protect workers down-wind from being put at risk by events up-
wind from their location. Among the most serious of these risks is 
miners being overcome by the products of combustion or an explosion.
    In Miner's Circular 50, "Explosions and Fires in Bituminous-Coal 
Mines" published by the Bureau of Mines in 

[[Page 9782]]
1954, the authors state that when air travels a long path through a 
mine, it gradually becomes depleted of oxygen and may become so 
contaminated with other gases that it no longer is healthful, or it may 
accumulate enough explosive gas to present an explosion hazard. The 
authors go on to state that when the air is divided into several 
splits, each traveling a short path, better air can be furnished to 
each group of persons in the mine. Further, if a local explosion or 
fire should occur, the poisonous gases evolved may be confined to one 
section and the force of the explosion and the gases may kill all the 
persons in that particular section but may not affect other sections of 
the mine. According to the authors, when a mine is ventilated by a 
continuous current of air, the miners on the return side of an 
explosion or fire probably will be killed or overcome by the poisonous 
gases and that judicious splitting of the air is a safeguard against 
this eventuality.
    Similarly, Stefanko states in the 1973 edition of the Society of 
Mining Engineers (SME) Engineering Handbook that splitting the air is 
recognized as being necessary for safety and presents only minimal 
power cost.
    The commenters implied that because longwall mining equipment is 
largely noncombustible, this danger is minimized for workers down-wind 
on an active mining section. This reasoning overlooks the fact, 
however, that the installation of a longwall is labor-intensive, 
involving cutting and welding in the presence of methane and coal, as 
well as machinery operating under load. These conditions add 
contaminants to the ventilating current, and increase the possibility 
of a fire or explosion. Likewise, a longwall being installed on the 
return side of an active mining section would expose the miners doing 
the installation to the dust and gases, and the results of a fire or 
explosion, from the section. Even with monitoring, miners would be put 
at risk as their opportunities for escape would be limited. For these 
reasons, the final rule does not adopt the commenters'' suggestion.
    One commenter also suggested that "approved ventilation controls" 
be required instead of specifying that overcasts, undercasts or other 
permanent ventilation controls be used to direct intake air. The 
commenter explained that this would allow operators the flexibility of 
submitting plans that allow the use of temporary controls in some 
instances.
    Temporary controls to split air are not as reliable as permanent 
controls. The first explosion at the Scotia Mine in 1976 which killed 
15 miners, was due in part to the improper use of a temporary 
ventilation control where a permanent control (i.e., an overcast) 
should have been used. More recently, the explosion that occurred 
during the set up of a longwall at the Golden Eagle Mine in 1991 which 
injured 11 miners involved the removal of two permanent ventilation 
controls and the replacement of these controls with temporary controls. 
As these and other accidents illustrate, the ventilation controls that 
deliver air to working areas are vitally important to miners'' safety. 
Therefore, the final rule requires that these controls be permanent in 
nature and not temporary.
    Another commenter indicated that the use of temporary controls 
would lower worker exposure to hazards by not requiring repeated 
handling of permanent control materials which can be heavy. Proper 
handling practices and modern materials can reduce the risk of injuries 
associated with handling construction materials. MSHA considers these 
risks lower than the dangers of using temporary controls in lieu of 
permanent controls.

Section 75.333 Ventilation Controls

    The primary means for directing air from the outside, through the 
mine openings, to the working areas and back to the surface is through 
the use of ventilation controls: either permanent controls, such as 
stoppings (walls), overcasts or undercasts (air bridges), and doors, or 
temporary controls, such as line brattice (curtains). Permanent 
ventilation controls are designed for long term use while temporary 
controls are intended for use on a short term basis. In general, 
Sec. 75.333 specifies where each type of control can be used and how 
each permanent control is to be constructed. It is essential that 
ventilation controls be correctly constructed, maintained, and properly 
located to provide ventilation to working sections and other areas 
where it is needed to dilute methane, respirable coal mine dust and 
other contaminants, and provide miners with a safe and healthful work 
environment.
    The final rule revises paragraphs (a), (b)(1), (b)(3), (b)(4) and 
(e)(1) of existing Sec. 75.333, and adds a new paragraph (h). Revisions 
to paragraphs (a) and (e)(1) address the durability of stoppings, while 
the revisions to (b)(1), (b)(3) and (b)(4) address ventilation controls 
required when continuous haulage systems are used. New paragraph (h) 
requires all permanent ventilation controls, including seals, to be 
maintained to serve the purpose for which they were built.
    The use of continuous haulage systems, particularly in low seam 
coal mines, is becoming more common. The final rule specifically 
addresses continuous haulage systems in paragraphs (b)(1), (b)(3) and 
(b)(4) of the rule and clarifies where temporary controls are an 
acceptable means of ventilation control when these systems are used. 
Continuous haulage systems utilize mobile bridge conveyors or similar 
mechanisms to transport coal directly from a continuous mining machine 
to a low profile belt. As the continuous mining machine moves from 
place to place, the continuous haulage system slides back and forth 
along a low profile conveyor belt using a "dolly" or other travel 
mechanism. The low profile conveyor belt then transports the coal to 
the section conveyor belt.
    The existing rule permits the use of temporary ventilation controls 
in lieu of permanent ventilation controls to separate continuous face 
haulage systems from return, intake, and primary escapeway entries in 
rooms developed 600 feet or less from the centerline of the entry from 
which the rooms were developed. This practice is consistent with 
longstanding MSHA policy, which recognizes that these rooms are used 
for a short duration and the minimum air quantity must be maintained 
regardless of the controls used.
    Existing paragraph (b)(1) allows temporary controls to separate 
intake and return air courses in rooms driven 600 feet or less from the 
centerline of the entry from which the room was developed. The final 
rule adds to existing paragraph (b)(1) the proposed language clarifying 
that the use of temporary controls in these rooms is also acceptable 
when continuous haulage systems are used. This change responds to 
commenters who point out that the rooms in which the continuous haulage 
systems are installed are continuously attended by the operators of the 
system and an immediate response to any safety related problem with the 
system or the ventilation controls would be expected. Commenters also 
noted that two or three rooms are often concurrently developed using a 
continuous haulage system and the life of the actively developing rooms 
is often less than three days. As a result of this short life, mining 
in these rooms is often completed before construction of permanent 
controls is finished. Also, access to the continuous haulage system is 
required through crosscuts for maintenance and operation of the system.
    Under paragraphs (b)(3) and (b)(4) the proposal would have required 
belt and 

[[Page 9783]]
intake separation to the outby travel point of the dolly and belt and 
primary escapeway separation to the inby most travel point. Commenters 
indicated confusion because of the distinction between intake and 
primary escapeway separation and believed that conflicts would exist. 
Commenters also suggested that the language proposed to address the use 
of temporary ventilation controls for continuous haulage systems was 
confusing and contradictory. The final rule revises the requirements of 
proposed paragraphs (b)(3) and (b)(4) to respond to these comments.
    Paragraph (b)(3) of the final rule retains the requirement that 
permanent controls be provided to separate belt conveyor haulageways 
from intake air courses when the air in the intake air course is used 
to provide air to active working places. The final rule also retains 
the proposed provision that when continuous haulage systems are used in 
rooms less than 600 feet from the centerline of the entry from which 
the rooms were developed, temporary stoppings or other temporary 
ventilation controls may be built and maintained to provide the 
required separation.
    Commenters stated that new technology may result in continuous 
haulage systems with the outby point of travel of the dolly extending 
considerably beyond the 600 feet distance. The commenters noted that 
such an extended length of temporary controls could result in 
unanticipated adverse consequences for the ventilation system, and 
suggested that a maximum distance of 300 feet outby the inby point of 
travel of the dolly be established for the use of temporary ventilation 
controls. MSHA agrees that extensive use of temporary ventilation 
controls can create problems, including excessive leakage and the 
possible short circuiting of air. The final rule, therefore, limits the 
distance that temporary controls may be used to separate continuous 
haulage systems from intake air courses, including the primary 
escapeway. The final rule permits temporary controls to be used from 
the point of deepest penetration of the conveyor belt entry to the most 
outby point of travel of the dolly or 600 feet, whichever distance is 
the less. As a result, 600 feet is the maximum linear distance of entry 
in which temporary controls may be used for separation of air courses. 
The 600 feet would be measured as a straight-line distance from the 
point of deepest penetration in the conveyor belt haulage entry. This 
approach comports with the 600 foot limit for the use of temporary 
stoppings in rooms and allows a reasonable use of temporary ventilation 
controls with continuous haulage systems, while preserving the 
integrity of the ventilation system. At present, MSHA would expect that 
the most outby point of travel of the dolly would govern since MSHA is 
not aware of any continuous haulage systems which travel more than 600 
feet outby the point of deepest penetration.
    Paragraph (b)(4) of the final rule continues to require permanent 
stoppings or other permanent ventilation control devices to separate 
the primary escapeway from the belt and trolley haulage entries, as 
required by Sec. 75.380(g). Commenters suggested that for the purposes 
of Sec. 75.380(g), the definition of loading point in proposed 
paragraph (b)(4) be revised to be the outby point of travel of the 
dolly as opposed to the inby point of travel. The final rule adopts 
this suggestion and requires separation by permanent stoppings to be 
maintained to the outby point of travel of the dolly or 600 feet from 
the point of deepest penetration, whichever distance is less, to 
separate the haulage entry from the primary escapeway. The provisions 
of Sec. 75.380(g) continue to allow the district manager to require a 
greater or lesser distance for this separation.
    In response to questions about acceptable construction methods and 
materials for permanent ventilation controls (excluding seals) MSHA 
proposed eliminating the definition of "durable" in paragraph (a) and 
to modify paragraph (e)(1). The proposal would have required these 
controls to be constructed in a manner and of materials that result in 
a construction that has been tested and shown to have a minimum 
strength of 39 pounds per square foot as tested under ASTM E72-80 
Section 12--Transverse Load-Specimen Vertical, load only (ASTM E72-80). 
The 8-inch hollow-core concrete block stopping with mortared joints, to 
which all other constructions were tied under the definition of durable 
in the existing standard, has been tested and shown to have a minimum 
strength of 39 pounds per square foot.
    MSHA received numerous comments questioning the validity of the 
ASTM E72-80 test for determining acceptability of underground 
ventilation controls. Commenters questioned the appropriateness of a 
strength requirement of 39 pounds per square foot and the relevance of 
this value to the in-mine conditions. After review, MSHA continues to 
believe that use of the ASTM E72-80 test to determine that the relative 
strength of a ventilation control construction is appropriate and the 
final rule retains this standard. However, MSHA sees merit in some of 
the suggestions made by commenters. Commenters suggested that some 
constructions can not be tested according to the ASTM test, some 
constructions that are widely used in coal mines do not meet the 39 
pound per square foot threshold, and the ASTM test can only be run at a 
limited number of locations nationwide.
    After reviewing all of the comments received and based on 
experience with various construction methods and materials used for 
permanent ventilation controls since the inception of the Mine Act, the 
final rule recognizes traditionally accepted construction methods for 
permanent ventilation controls, and retains the ASTM test for new 
materials and methods. Controls made with new materials or methods must 
be comparable in strength to controls made with traditionally accepted 
materials or methods.
    Since the inception of the Mine Act, a number of traditionally 
accepted construction methods have performed adequately and have served 
their intended function of separating air courses. These traditionally 
accepted construction methods are: 8-inch and 6-inch concrete blocks 
(both hollow-core and solid) with mortared joints; 8-inch and 6-inch 
concrete blocks dry-stacked and coated on both sides with a strength 
enhancing sealant suitable for dry-stacked stoppings; 8-inch and 6-inch 
concrete blocks dry-stacked and coated on the high pressure side with a 
strength enhancing sealant suitable for dry-stacked stoppings; steel 
stoppings (minimum 20-gauge) with seams sealed using manufacturer's 
recommended tape and with the tape and perimeter of the metal stopping 
coated with a suitable mine sealant; and lightweight incombustible 
cementatious masonry blocks coated on the joints and perimeter with a 
strength enhancing sealant suitable for dry-stacked stoppings. In 
addition, 4-inch concrete blocks may be used in the above applications 
in seam heights less than 48 inches. Tongue and groove 4-inch concrete 
blocks coated on both sides with a strength enhancing sealant suitable 
for dry-stacked stoppings may be used in coal seams of any height. The 
sealants referred to in this paragraph would be applied in the 
thickness recommended by the manufacturer. MSHA maintains a list of 
sealants which may be used for the above applications. This list is 
available at each MSHA District Office. The final rule would continue 
to permit these traditionally accepted construction 

[[Page 9784]]
methods to be acceptable for the construction of ventilation controls.
    For new construction methods or materials other than those used for 
the traditionally accepted constructions identified above, the final 
rule requires that the strength be equal to or greater than the 
traditionally accepted in-mine controls. Tests may be performed under 
ASTM E72-80 Section 12--Transverse Load-Specimen Vertical, load only, 
or the operator may conduct comparative in-mine tests. In-mine tests 
must be designed to demonstrate the comparative strength of the 
proposed construction and a traditionally accepted in-mine control.
    As with the existing rule, the final rule would require, in 
paragraph (e)(1)(ii), that all overcasts, undercasts, shaft partitions, 
permanent stoppings, and regulators, installed after November 15, 1992, 
be constructed of noncombustible material. Also, like the existing 
standard, the final rule lists materials that would be suitable for 
these controls. The final rule would also continue to prohibit 
ventilation controls installed after November 15, 1992, from being 
constructed of aluminum.
    Paragraph (h) of the proposal would have required that all 
permanent ventilation controls, including seals, be maintained to serve 
the purpose for which they were built. The final rule retains proposed 
paragraph (h) with one revision. One commenter stated that the 
paragraph should require all ventilation controls, including temporary 
controls, to be maintained to serve the purpose for which they were 
built. Given the importance of temporary controls devices in providing 
for adequate ventilation, the final rule requires all ventilation 
controls, both permanent and temporary, including all doors and seals, 
to be maintained to serve the purpose for which they were built. This 
standard applies to all ventilation controls, regardless of the 
construction date.
    Relative to seal maintenance, MSHA does not intend that the 
maintenance requirement be applied to seals located within another 
sealed area. Additionally, the rule does not apply to seals which have 
become consumed within a gob area which is ventilated and evaluated in 
a manner approved in the mine ventilation plan.
    One commenter raised several questions concerning what MSHA would 
consider to be an acceptable temporary stopping. MSHA has not defined 
the term "temporary ventilation control" in the rule. The commenter 
stated that, in the preamble to the proposal, MSHA refers to "properly 
constructed" temporary stoppings but does not include a standard for 
construction or installation and maintenance of temporary stoppings. 
The commenter adds that temporary ventilation controls are a source of 
potential leakage and are often susceptible to damage from roof and rib 
falls and from mobile equipment. The commenter also refers to several 
accidents where failure to maintain permanent or temporary ventilation 
controls was a critical factor in the accident.
    MSHA agrees that to properly direct the flow of air and provide for 
adequate face ventilation, temporary controls, as well as all permanent 
ventilation controls, must be installed and maintained in an adequate 
manner to control leakage. MSHA has accepted as temporary controls, 
check curtains or other flame- resistant material approved by MSHA that 
are constructed and installed in such a manner to minimize leakage. As 
required by paragraph (h) of this section of the final rule, these 
controls must be maintained to serve the purpose for which they were 
built.

Section 75.334 Worked-Out Areas and Areas Where Pillars Are Being Recovered

    Worked-out areas, areas where coal extraction has been completed, 
can pose deadly hazards to miners, including an explosive methane 
accumulation, irrespirable atmosphere, and the possibility of fire from 
spontaneous combustion. Section 75.334 establishes the requirements for 
ventilation of these areas to mitigate these hazards. In general, 
Sec. 75.334 requires that following mining, these areas are to be 
sealed or ventilated. Section 75.334 also specifies the requirements 
for evaluating the effectiveness of the ventilation of worked-out areas 
so operators can determine that the ventilation system is functioning 
as intended.
    The final rule revises paragraph (e) of the existing Sec. 75.334. 
Existing paragraph (e) requires that each mining system be designed so 
that worked-out areas can be sealed. The final rule adds to paragraph 
(e) the proposed requirement that the location and sequence of 
construction of proposed seals be specified in the approved mine 
ventilation plan. Improper location and sequencing of seal construction 
can have a dangerous effect on mine air quality and ventilation. As the 
proper location and sequence of construction of seals is a mine-by-mine 
determination, the mine ventilation plan provides the most workable 
mechanism by which to assure proper air quality and ventilation of the 
mine.
    Several commenters objected to including seal construction sequence 
as part of the information to be submitted for approval in the mine 
ventilation plan. Their rationale was that mining conditions change and 
could result in a change in the sequence of seal construction. The 
construction might then be delayed while approval for the change is 
obtained. These commenters suggested that in some cases, delays in seal 
construction could result in a hazard to miners. Other commenters 
stated that the sequence of construction of seals is more appropriately 
and more easily shown on the mine ventilation map required by 
Sec. 75.372. Another commenter stated that the sequence of construction 
should be subject to approval because the placement of seals if 
improperly installed can cause adverse effects on the ventilation 
system and gob gases. MSHA is sensitive to the concern that a delay in 
approval could result in a hazard to miners and, as explained in the 
preamble discussion of Sec. 75.370, if a delay in seal construction 
would result in a hazard to miners the review and approval of the plan 
can be expedited.
    MSHA agrees with the commenter that the location and sequence of 
seal construction may be more easily, that is, more clearly shown on 
the mine map required by Sec. 75.372 than in the written text of the 
plan submitted under Sec. 75.371. The existing standard permits 
appropriate information required under Sec. 75.371 to be shown on the 
map required by Sec. 75.372. The effect is that the information both 
appears on the ventilation map and in the ventilation plan and is 
subject to approval. The discussion of Sec. 75.371(bb) further 
addresses this point.
    Spontaneous combustion is the process through which coal or other 
materials self heat by the absorption of oxygen. Paragraph (f) of 
Sec. 75.334 addresses mines with a demonstrated history of spontaneous 
combustion and those located in coal seams determined to be susceptible 
to spontaneous combustion. Paragraph (f) requires that the approved 
mine ventilation plan for these mines specify the measures that will be 
used to detect methane, carbon monoxide, and oxygen concentrations 
during and after pillar recovery, and in worked-out areas where no 
pillars have been recovered; the actions that will be taken to protect 
miners from the hazards of spontaneous combustion; and, if a bleeder 
system will not be used, the methods that will be used to control 
spontaneous combustion, accumulations of methane-air mixtures, and 
other gases, dusts, and fumes in the worked-out area. 

[[Page 9785]]

    Through meetings with various segments of the mining community, 
MSHA became aware of a concern that paragraph (f) of existing 
Sec. 75.334 may have been promulgated without the public being provided 
the opportunity to adequately comment. Although MSHA believes that 
existing paragraph (f) was promulgated properly, the Agency reproposed 
paragraph (f) with wording identical to that used in existing 
Sec. 75.334. The purpose of the reproposal was to assure MSHA received 
and considered all pertinent comments.
    Several commenters to the existing rule suggested that bleeder 
systems should not be required for all mines. These commenters stated 
that in some mines the practice of ventilating worked-out areas 
increases the risk of spontaneous combustion by supplying oxygen to 
combustion-prone materials in these areas. They also requested that the 
final rule promulgated in 1992 include provisions to address 
spontaneous combustion. MSHA acknowledged the need to reduce the flow 
of oxygen to areas where there is a likelihood of spontaneous 
combustion, and included in the 1992 rule requirements for mine 
ventilation plans to address spontaneous combustion in mines with a 
demonstrated history of this hazard or mines that are located in coal 
seams determined to be susceptible to spontaneous combustion.
    Experience gained through application of the existing standard has 
demonstrated that a limited number of mines have experienced 
spontaneous combustion problems. Studies by the Bureau of Mines have 
identified the volatile properties of coal seams and have determined 
that certain seams are susceptible to spontaneous combustion. The final 
rule is directed to mines in these seams.
    MSHA is not suggesting that all coal mines will meet the test to 
show susceptibility to spontaneous combustion. A demonstrated history 
or the determination of susceptibility to spontaneous combustion is a 
prerequisite to the applicability of paragraph (f). While it is true 
that all coal oxidizes when exposed to air, this fact is not sufficient 
to make the determination that a coal seam is susceptible to 
spontaneous combustion. MSHA would expect that absent a demonstrated 
history of spontaneous combustion in a mine, an operator would provide 
the necessary data to demonstrate that the mine is susceptible to 
spontaneous combustion so that the provisions of paragraph (f) should 
apply. A number of methods are used to determine the self heating 
tendency of a coal.
    However, MSHA is also mindful that some mines that have a 
spontaneous combustion problem may be unable to reduce the oxygen 
content to a sufficiently low level to mitigate spontaneous combustion. 
For these mines, a bleederless system may not be appropriate. To 
illustrate, it is well known that the oxygen level in a gob varies 
depending on the location where the measurement is made. For example, 
the periphery of a gob normally will have higher oxygen levels than the 
interior of the gob. The oxygen level in the interior of the gob is 
critical when dealing with spontaneous combustion. If conditions are 
such that the oxygen content in critical areas within a gob cannot be 
reduced below that necessary for a methane ignition to occur, a bleeder 
system may provide the most safety. MSHA specifically solicited comment 
on this subject; however, none was received.
    Under paragraph (f)(1), the approved ventilation plans for mines 
that have or are susceptible to spontaneous combustion must specify 
measures to detect methane, carbon monoxide, and oxygen concentrations 
in worked-out areas. These measures must be taken during and after 
pillar recovery and in worked-out areas where no pillars have been 
recovered. The purpose of these measures is to determine if worked-out 
areas will be ventilated or sealed. If the methane concentration or 
other hazards in the worked-out area cannot be controlled while the 
mine is limiting airflow to avoid spontaneous combustion, it may be 
necessary to seal or to ventilate the worked-out area using a bleeder 
system. These measures also help to determine the extent to which the 
worked-out areas can be ventilated without increasing the spontaneous 
combustion hazard.
    Under the provisions of paragraph (f)(2) the operator is required 
to specify in the mine ventilation plan the actions that will be taken 
to protect miners from the hazards of spontaneous combustion. 
Protections from the hazards of spontaneous combustion might include: 
Additional continuous monitoring of fire gases at strategic locations 
underground, increased air sample collection and analysis, trending of 
air contaminant data, increased examinations, and changes to the mine 
ventilation system such as redistribution of air or pressure balancing. 
This requirement would be triggered if the mine has a demonstrated 
history of spontaneous combustion, or, if an evaluation of the 
susceptibility of the coal seam to spontaneous combustion leads to a 
mine operator determination that a bleeder system should not be used.
    One commenter stated that this rule is unnecessary because only a 
limited number of mines actually have a demonstrated spontaneous 
combustion problem. The commenter suggested that the petition for 
modification (variance) process should be used to address this issue, 
which would allow miners representatives to participate. The final rule 
does not adopt this approach. To the extent practicable, an objective 
of this rulemaking is to reduce the need for exceptions and paperwork. 
In this case, the existing mine ventilation plan process provides a 
ready-made mechanism for establishing the precautions necessary, on a 
mine-by-mine basis, to protect miners from the hazards of spontaneous 
combustion in a timely manner. In addition, under the final rule, 
miners representatives are afforded input into the mine ventilation 
plan.
    Another commenter stated that paragraph (f) should be directed more 
to the detection and control of spontaneous combustion and not solely 
at its prevention. The commenter offered examples of detection and 
control techniques that could be used.
    MSHA agrees that spontaneous combustion prevention, detection and 
control are all important when dealing with spontaneous combustion. The 
final rule recognizes, however, that while prevention is the goal, 
instances of spontaneous combustion will occur.
    Another commenter stated that the preamble to the proposal was not 
correct in that it implied a need to limit airflow to avoid spontaneous 
combustion. The commenter states that, to avoid spontaneous combustion, 
miners must create a near-zero pressure differential across most areas 
of concern. MSHA agrees that creating a "near-zero pressure 
differential" will have the desired effect of limiting the airflow. In 
a paper entitled "Examination of Bleederless Ventilation Practices for 
Spontaneous Combustion Control in U. S. Coal Mines" presented at the 
7th U.S. Mine Ventilation Symposium in June 1995, the authors report 
that their study revealed that restricting airflow into mined-out areas 
is recognized world-wide as a spontaneous combustion control measure 
and that when designing a bleederless ventilation system critical 
attention must be given to mine layout, seal construction, methane drainage,
regulations, monitoring, and emergency procedures. In 
discussing the subject of air leakage, Koenning in a paper entitled 
"Spontaneous Combustion in Coal Mines" 

[[Page 9786]]
 presented at the 4th U.S. Mine Ventilation Symposium in June 
1989, identified air leakage as the most often cited cause of 
spontaneous combustion. In both of these papers, the authors emphasize 
the need to properly design a bleederless ventilation system to reduce 
the likelihood of spontaneous combustion and achieve the level of 
worker safety desired. MSHA agrees with these authors that a 
bleederless ventilation system must be designed to encompass all of the 
factors identified. It was suggested by one commenter that measurement 
of carbon dioxide should be included in the requirements of paragraph 
(f). In discussing the gases required to be measured (methane, oxygen, 
and carbon monoxide), the commenter stated that these gases alone will 
not aid in the detection of spontaneous combustion in its incipient or 
developed stage. The commenter suggested that miners be required to 
monitor for carbon dioxide because, in the opinion of the commenter, 
the trend in the ratio CO/CO<INF>2 is the only viable predictor.
    MSHA sees merit in the measurement of carbon dioxide as well as 
other products of combustion to assist in the detection of spontaneous 
combustion. However, the ratio CO/CO<INF>2 is not the only viable 
predictor of spontaneous combustion. One researcher suggested that 
carbon monoxide production is the earliest, detectable effect of 
spontaneous heating. Others have suggested, following a series of 
tests, that four gas ratios clearly indicated the development of 
thermal runaway, but only the CO<INF>2- <triangle>O<INF>2 ratio gave
an early warning of the heating in the coalbed.
    As can be seen, a number of methods of predicting the onset of 
spontaneous combustion have been suggested. While paragraph (f)(1) 
requires only the measurement of methane, oxygen, and carbon monoxide, 
MSHA would not discourage operators from incorporating, as part of the 
mine ventilation plan, any or all of these methods as well as other 
appropriate methods to aid in the early detection of spontaneous 
combustion.