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MSHA Federal Register Document
Rules and Regulations

Volume 61, Number 18, Page 2543



List of Subjects in 30 CFR Part 75

    Escapeways, Mine safety and health, Underground coal mines, 
Ventilation.

    Dated: March 4, 1996.
J. Davitt McAteer,
Assistant Secretary for Mine Safety and Health.

    Accordingly, part 75, subchapter O, chapter I, title 30 of the Code 
of Federal Regulations is amended as follows:

PART 75--MANDATORY SAFETY STANDARDS--UNDERGROUND COAL MINES

    1. The authority citation for part 75 is revised to read as 
follows:

    Authority: 30 U.S.C. 811.

    2. Subpart D of part 75 is revised to read as follows: 

[[Page 9829]]


Subpart D--Ventilation

Sec.
75.300  Scope.
75.301  Definitions.
75.302  Main mine fans.
75.310  Installation of main mine fans.
75.311  Main mine fan operation.
75.312  Main mine fan examinations and records.
75.313  Main mine fan stoppage with persons underground.
75.320  Air quality detectors and measurement devices.
75.321  Air quality.
75.322  Harmful quantities of noxious gases.
75.323  Actions for excessive methane.
75.324  Intentional changes in the ventilation system.
75.325  Air quantity.
75.326  Mean entry air velocity.
75.327  Air courses and trolley haulage systems.
75.330  Face ventilation control devices.
75.331  Auxiliary fans and tubing.
75.332  Working sections and working places.
75.333  Ventilation controls.
75.334  Worked-out areas and areas where pillars are being 
recovered.
75.335  Construction of seals.
75.340  Underground electrical installations.
75.341  Direct-fired intake air heaters.
75.342  Methane monitors.
75.343  Underground shops.
75.344  Compressors.
75.350  Air courses and belt haulage entries.
75.351  Atmospheric monitoring system (AMS).
75.352  Return air courses.
75.360  Preshift examination.
75.361  Supplemental examination.
75.362  On-shift examination.
75.363  Hazardous conditions; posting, correcting and recording.
75.364  Weekly examination.
75.370  Mine ventilation plan; submission and approval.
75.371  Mine ventilation plan; contents.
75.372  Mine ventilation map.
75.373  Reopening mines.
75.380  Escapeways; bituminous and lignite mines.
75.381  Escapeways; anthracite mines.
75.382  Mechanical escape facilities.
75.383  Escapeway maps and drills.
75.384  Longwall and shortwall travelways.
75.385  Opening new mines.
75.386  Final mining of pillars.
75.388  Boreholes in advance of mining.
75.389  Mining into inaccessible areas.


Sec. 75.300 Scope.

    This subpart sets requirements for underground coal mine 
ventilation.


Sec. 75.301 Definitions.

    In addition to the applicable definitions in Sec. 75.2, the 
following definitions apply in this subpart.
    Air course. An entry or a set of entries separated from other 
entries by stoppings, overcasts, other ventilation control devices, or 
by solid blocks of coal or rock so that any mixing of air currents 
between each is limited to leakage.
    Incombustible. Incapable of being burned.
    Intake air. Air that has not yet ventilated the last working place 
on any split of any working section, or any worked-out area, whether 
pillared or nonpillared.
    Intrinsically safe. Incapable of releasing enough electrical or 
thermal energy under normal or abnormal conditions to cause ignition of 
a flammable mixture of methane or natural gas and air of the most 
easily ignitable composition.
    Noncombustible Structure or Area. Describes a structure or area 
that will continue to provide protection against flame spread for at 
least 1 hour when subjected to a fire test incorporating an ASTM E119-
88 time/temperature heat input, or equivalent.
    Noncombustible Material. Describes a material which when used to 
construct a ventilation control results in a control that will continue 
to serve its intended function for 1 hour when subjected to a fire test 
incorporating an ASTM E119-88 time/temperature heat input, or 
equivalent.
    Return air. Air that has ventilated the last working place on any 
split of any working section or any worked-out area whether pillared or 
nonpillared. If air mixes with air that has ventilated the last working 
place on any split of any working section or any worked-out area, 
whether pillared or nonpillared, it is considered return air. For the 
purposes of Sec. 75.507-1, air that has been used to ventilate any 
working place in a coal producing section or pillared area, or air that 
has been used to ventilate any working face if such air is directed 
away from the immediate return is return air. Notwithstanding the 
definition of intake air, for the purpose of ventilation of structures, 
areas or installations that are required by this subpart D to be 
ventilated to return air courses, and for ventilation of seals, other 
air courses may be designated as return air courses by the operator 
only when the air in these air courses will not be used to ventilate 
working places or other locations, structures, installations or areas 
required to be ventilated with intake air.
    Worked-out area. An area where mining has been completed, whether 
pillared or nonpillared, excluding developing entries, return air 
courses, and intake air courses.


Sec. 75.302 Main mine fans.

    Each coal mine shall be ventilated by one or more main mine fans. 
Booster fans shall not be installed underground to assist main mine 
fans except in anthracite mines. In anthracite mines, booster fans 
installed in the main air current or a split of the main air current 
may be used provided their use is approved in the ventilation plan.


Sec. 75.310 Installation of main mine fans.

    (a) Each main mine fan shall be--
    (1) Installed on the surface in an incombustible housing;
    (2) Connected to the mine opening with incombustible air ducts;
    (3) Equipped with an automatic device that gives a signal at the 
mine when the fan either slows or stops. 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. 
This person shall be provided with two-way communication with the 
working sections and work stations where persons are routinely assigned 
to work for the majority of a shift;
    (4) Equipped with a pressure recording device or system. Mines 
permitted to shut down main mine fans under Sec. 75.311 and which do 
not have a pressure recording device installed on main mine fans shall 
have until March 11, 1997 to install a pressure recording device or 
system on all main mine fans. If a device or system other than a 
circular pressure recorder is used to monitor main mine fan pressure, 
the monitoring device or system shall provide a continuous graph or 
continuous chart of the pressure as a function of time. At not more 
than 7-day intervals, a hard copy of the continuous graph or chart 
shall be generated or the record of the fan pressure shall be stored 
electronically. When records of fan pressure are stored electronically, 
the system used to store these records shall be secure and not 
susceptible to alteration and shall be capable of storing the required 
data. Records of the fan pressure shall be retained at a surface 
location at the mine for at least 1 year and be made available for 
inspection by authorized representatives of the Secretary and the 
representative of miners;
    (5) Protected by one or more weak walls or explosion doors, or a 
combination of weak walls and explosion doors, located in direct line 
with possible explosive forces;
    (6) Except as provided under paragraph (e) of this section, offset 
by at least 15 feet from the nearest side of the mine opening unless an 
alternative method of protecting the fan and its associated components 
is approved in the ventilation plan. 

[[Page 9830]]

    (b)(1) If an electric motor is used to drive a main mine fan, the 
motor shall operate from a power circuit independent of all mine power 
circuits.
    (2) If an internal combustion engine is used to drive a main mine 
fan--
    (i) The fuel supply shall be protected against fires and 
explosions;
    (ii) The engine shall be installed in an incombustible housing and 
be equipped with a remote shut-down device;
    (iii) The engine and the engine exhaust system shall be located out 
of direct line of the air current exhausting from the mine; and
    (iv) The engine exhaust shall be vented to the atmosphere so that 
the exhaust gases do not contaminate the mine intake air current or any 
enclosure.
    (c) If a main mine fan monitoring system is used under Sec. 75.312, 
the system shall--
    (1) Record, as described in paragraph (a)(4) the mine ventilating 
pressure;
    (2) Monitor bearing temperature, revolutions per minute, vibration, 
electric voltage, and amperage;
    (3) 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; 
and
    (4) Be equipped with an automatic device that signals when--
    (i) An electrical or mechanical deficiency exists in the monitoring 
system; or
    (ii) A sudden increase or loss in mine ventilating pressure occurs.
    (5) Provide monitoring, records, printouts, and signals required by 
paragraphs (c)(1) through (c)(4) at a surface location at the mine 
where a responsible person designated by the operator is always on duty 
and where signals from the monitoring system can be seen or heard while 
anyone is underground. This person shall be provided with two-way 
communication with the working sections and work stations where persons 
are routinely assigned to work for the majority of a shift.
    (d) Weak walls and explosion doors shall have cross-sectional areas 
at least equal to that of the entry through which the pressure from an 
explosion underground would be relieved. A weak wall and explosion door 
combination shall have a total cross-sectional area at least equal to 
that of the entry through which the pressure from an explosion 
underground would be relieved.
    (e) If a mine fan is installed in line with an entry, a slope, or a 
shaft--
    (1) The cross-sectional area of the pressure relief entry shall be 
at least equal to that of the fan entry;
    (2) The fan entry shall be developed out of direct line with 
possible explosive forces;
    (3) The coal or other solid material between the pressure relief 
entry and the fan entry shall be at least 2,500 square feet; and
    (4) The surface opening of the pressure relief entry shall be not 
less than 15 feet nor more than 100 feet from the surface opening of 
the fan entry and from the underground intersection of the fan entry 
and pressure relief entry.
    (f) In mines ventilated by multiple main mine fans, incombustible 
doors shall be installed so that if any main mine fan stops and air 
reversals through the fan are possible, the doors on the affected fan 
automatically close.


Sec. 75.311 Main mine fan operation.

    (a) Main mine fans shall be continuously operated, except as 
otherwise approved in the ventilation plan, or when intentionally 
stopped for testing of automatic closing doors and automatic fan signal 
devices, maintenance or adjustment of the fan, or to perform 
maintenance or repair work underground that cannot otherwise be made 
while the fan is operating.
    (b) Except as provided in paragraph (c) of this section, when a 
main mine fan is intentionally stopped and the ventilating quantity 
provided by the fan is not maintained by a back-up fan system--
    (1) Only persons necessary to evaluate the effect of the fan 
stoppage or restart, or to perform maintenance or repair work that 
cannot otherwise be made while the fan is operating, shall be permitted 
underground;
    (2) Mechanized equipment shall be shut off before stopping the fan; 
and
    (3) Electric power circuits entering underground areas of the mine 
shall be deenergized.
    (c) When a back-up fan system is used that does not provide the 
ventilating quantity provided by the main mine fan, persons may be 
permitted in the mine and electric power circuits may be energized as 
specified in the approved ventilation plan.
    (d) 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 equivalent mine official, a 
designated certified person acting for the mine foreman or equivalent 
mine official shall be notified immediately, and appropriate action or 
repairs shall be instituted promptly.
    (e) While persons are underground, a responsible person designated 
by the operator shall always be at a surface location where each main 
mine fan signal can be seen or heard.
    (f) The area within 100 feet of main mine fans and intake air 
openings shall be kept free of combustible material, unless alternative 
precautions necessary to provide protection from fire or other products 
of combustion are approved in the ventilation plan.
    (g) If multiple mine fans are used, the mine ventilation system 
shall be designed and maintained to eliminate areas without air 
movement.
    (h) Any atmospheric monitoring system operated during fan stoppages 
shall be intrinsically safe.


Sec. 75.312 Main mine fan examinations and records.

    (a) To assure electrical and mechanical reliability of main mine 
fans, each main mine fan and its associated components, including 
devices for measuring or recording mine ventilation pressure, shall be 
examined for proper operation by a trained person designated by the 
operator. Examinations of main mine fans shall be made at least once 
each day that the fan operates, unless a fan monitoring system is used. 
No examination is required on any day when no one, including certified 
persons, goes underground, except that an examination shall be 
completed prior to anyone entering the mine.
    (b)(1) If a main mine fan monitoring system is used, a trained 
person designated by the operator shall--
    (i) At least once each day review the data provided by the fan 
monitoring system to assure that the fan and the fan monitoring system 
are operating properly. No review is required on any day when no one, 
including certified persons, goes underground, except that a review of 
the data shall be performed prior to anyone entering the underground 
portion of the mine. Data reviewed should include the fan pressure, 
bearing temperature, revolutions per minute, vibration, electric 
voltage, and amperage; and
    (ii) At least every 7 days--
    (A) Test the monitoring system for proper operation; and
    (B) Examine each main mine fan and its associated components to 
assure electrical and mechanical reliability of main mine fans.
    (2) If the monitoring system malfunctions, the malfunction shall be 
corrected, or paragraph (a) of this section shall apply.
    (c) At least every 31 days, the automatic fan signal device for 
each main mine fan shall be tested by stopping the fan. Only persons 

[[Page 9831]]
necessary to evaluate the effect of the fan stoppage or restart, or to 
perform maintenance or repair work that cannot otherwise be made while 
the fan is operating, shall be permitted underground. Notwithstanding 
the requirement of Sec. 75.311(b)(3), underground power may remain 
energized during this test provided no one, including persons 
identified in Sec. 75.311(b)(1), is underground. If the fan is not 
restarted within 15 minutes, underground power shall be deenergized and 
no one shall enter any underground area of the mine until the fan is 
restarted and an examination of the mine is conducted as described in 
Sec. 75.360 (b) through (e) and the mine has been determined to be 
safe.
    (d) At least every 31 days, the automatic closing doors in multiple 
main mine fan systems shall be tested by stopping the fan. Only persons 
necessary to evaluate the effect of the fan stoppage or restart, or to 
perform maintenance or repair work that cannot otherwise be made while 
the fan is operating, shall be permitted underground. Notwithstanding 
the provisions of Sec. 75.311, underground power may remain energized 
during this test provided no one, including persons identified in 
Sec. 75.311(b)(1), is underground. If the fan is not restarted within 
15 minutes, underground power shall be deenergized and no one shall 
enter any underground area of the mine, until the fan is restarted and 
an examination of the mine is conducted as described in Sec. 75.360 (b) 
through (e) and the mine has been determined to be safe.
    (e) Circular main mine fan pressure recording charts shall be 
changed before the beginning of a second revolution.
    (f)(1) Certification. Persons making main mine fan examinations 
shall certify by initials and date at the fan or another location 
specified by the operator that the examinations were made. Each 
certification shall identify the main mine fan examined.
    (2) Persons reviewing data produced by a main mine fan monitoring 
system shall certify by initials and date on a printed copy of the data 
from the system that the review was completed. In lieu of certification 
on a copy of the data, the person reviewing the data may certify 
electronically that the review was completed. Electronic certification 
shall be by handwritten initials and date in a computer system so as to 
be secure and not susceptible to alteration.
    (g)(1) Recordkeeping. By the end of the shift on which the 
examination is made, persons making main mine fan examinations shall 
record all uncorrected defects that may affect the operation of the fan 
that are not corrected by the end of that shift. Records shall be 
maintained in a secure book that is not susceptible to alteration or 
electronically in a computer system so as to be secure and not 
susceptible to alteration.
    (2) When a fan monitoring system is used in lieu of the daily fan 
examination--
    (i) The certified copies of data produced by fan monitoring systems 
shall be maintained separate from other computer-generated reports or 
data; and
    (ii) A record shall be made of any fan monitoring system 
malfunctions, electrical or mechanical deficiencies in the monitoring 
system and any sudden increase or loss in mine ventilating pressure. 
The record shall be made by the end of the shift on which the review of 
the data is completed and shall be maintained in a secure book that is 
not susceptible to alteration or electronically in a computer system so 
as to be secure and not susceptible to alteration.
    (3) By the end of the shift on which the monthly test of the 
automatic fan signal device or the automatic closing doors is 
completed, persons making these tests shall record the results of the 
tests. Records shall be maintained in a secure book that is not 
susceptible to alteration or electronically in a computer system so as 
to be secure and not susceptible to alteration.
    (h) Retention period. Records, including records of mine fan 
pressure and the certified copies of data produced by fan monitoring 
systems, shall be retained at a surface location at the mine for at 
least 1 year and shall be made available for inspection by authorized 
representatives of the Secretary and the representative of miners.


Sec. 75.313 Main mine fan stoppage with persons underground.

    (a) If a main mine fan stops while anyone is underground and the 
ventilating quantity provided by the fan is not maintained by a back-up 
fan system--
    (1) Electrically powered equipment in each working section shall be 
deenergized;
    (2) Other mechanized equipment in each working section shall be 
shut off; and
    (3) Everyone shall be withdrawn from the working sections and areas 
where mechanized mining equipment is being installed or removed.
    (b) If ventilation is restored within 15 minutes after a main mine 
fan stops, certified persons shall examine for methane in the working 
places and in other areas where methane is likely to accumulate before 
work is resumed and before equipment is energized or restarted in these 
areas.
    (c) If ventilation is not restored within 15 minutes after a main 
mine fan stops--
    (1) Everyone shall be withdrawn from the mine;
    (2) Underground electric power circuits shall be deenergized. 
However, circuits necessary to withdraw persons from the mine need not 
be deenergized if located in areas or haulageways where methane is not 
likely to migrate to or accumulate. These circuits shall be deenergized 
as persons are withdrawn; and
    (3) Mechanized equipment not located on working sections shall be 
shut off. However, mechanized equipment necessary to withdraw persons 
from the mine need not be shut off if located in areas where methane is 
not likely to migrate to or accumulate.
    (d)(1) When ventilation is restored--
    (i) No one other than designated certified examiners shall enter 
any underground area of the mine until an examination is conducted as 
described in Sec. 75.360(b) through (e) and the area has been 
determined to be safe. 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 ventilation plan.
    (ii) Underground power circuits shall not be energized and 
nonpermissible mechanized equipment shall not be started or operated in 
an area until an examination is conducted as described in 
Sec. 75.360(b) through (e) and the area has been determined to be safe, 
except that designated certified examiners may use nonpermissible 
transportation equipment in intake airways to facilitate the making of 
the required examination.
    (2) If ventilation is restored to the mine before miners reach the 
surface, the miners may return to underground working areas only after 
an examination of the areas is made by a certified person and the areas 
are determined to be safe.
    (e) Any atmospheric monitoring system operated during fan stoppages 
shall be intrinsically safe.


Sec. 75.320 Air quality detectors and measurement devices.

    (a) Tests for methane shall be made by a qualified person with MSHA 
approved detectors that are maintained in permissible and proper 
operating condition and calibrated with a known 

[[Page 9832]]
methane-air mixture at least once every 31 days.
    (b) Tests for oxygen deficiency shall be made by a qualified person 
with MSHA approved oxygen detectors that are maintained in permissible 
and proper operating condition and that can detect 19.5 percent oxygen 
with an accuracy of <plus-minus>0.5 percent. The oxygen detectors shall 
be calibrated at the start of each shift that the detectors will be 
used.
    (c) Handheld devices that contain electrical components and that 
are used for measuring air velocity, carbon monoxide, oxides of 
nitrogen, and other gases shall be approved and maintained in 
permissible and proper operating condition.
    (d) An oxygen detector approved by MSHA shall be used to make tests 
for oxygen deficiency required by the regulations in this part. 
Permissible flame safety lamps may only be used as a supplementary 
testing device.
    (e) Maintenance of instruments required by paragraphs (a) through 
(d) of this section shall be done by persons trained in such 
maintenance.


Sec. 75.321 Air quality.

    (a)(1) The air in areas where persons work or travel, except as 
specified in paragraph (a)(2) of this section, shall 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 shall be 
sufficient to dilute, render harmless, and carry away flammable, 
explosive, noxious, and harmful gases, dusts, smoke, and fumes.
    (2) The air in areas of bleeder entries and worked-out areas where 
persons work or travel shall contain at least 19.5 percent oxygen, and 
carbon dioxide levels shall not exceed 0.5 percent time weighted 
average and 3.0 percent short term exposure limit.
    (b) Notwithstanding the provisions of Sec. 75.322, for the purpose 
of preventing explosions from gases other than methane, the following 
gases shall not be permitted to accumulate in excess of the 
concentrations listed below:
    (1) Carbon monoxide (CO)--2.5 percent
    (2) Hydrogen (H<INF>2)--.80 percent
    (3) Hydrogen sulfide (H<INF>2S)--.80 percent
    (4) Acetylene (C<INF>2H<INF>2)--.40 percent
    (5) Propane (C<INF>3H<INF>8)--.40 percent
    (6) MAPP (methyl-acetylene-propylene-propodiene)--.30 percent


Sec. 75.322 Harmful quantities of noxious gases.

    Concentrations of noxious or poisonous gases, other than carbon 
dioxide, shall not exceed the current threshold limit values (TLV) as 
specified and applied by the ACGIH. Detectors or laboratory analysis of 
mine air samples shall be used to determine the concentrations of 
harmful, noxious, or poisonous gases.


Sec. 75.323 Actions for excessive methane.

    (a) Location of tests. Tests for methane concentrations under this 
section shall be made at least 12 inches from the roof, face, ribs, and 
floor.
    (b) Working places and intake air courses.
    (1) When 1.0 percent or more methane is present in a working place 
or an intake air course, including an air course in which a belt 
conveyor is located, or in an area where mechanized mining equipment is 
being installed or removed--
    (i) Except intrinsically safe atmospheric monitoring systems (AMS), 
electrically powered equipment in the affected area shall be 
deenergized, and other mechanized equipment shall be shut off;
    (ii) Changes or adjustments shall be made at once to the 
ventilation system to reduce the concentration of methane to less than 
1.0 percent; and
    (iii) No other work shall be permitted in the affected area until 
the methane concentration is less than 1.0 percent.
    (2) When 1.5 percent or more methane is present in a working place 
or an intake air course, including an air course in which a belt 
conveyor is located, or in an area where mechanized mining equipment is 
being installed or removed--
    (i) Everyone except those persons referred to in Sec. 104(c) of the 
Act shall be withdrawn from the affected area; and
    (ii) Except for intrinsically safe AMS, electrically powered 
equipment in the affected area shall be disconnected at the power 
source.
    (c) Return air split. (1) When 1.0 percent or more methane is 
present in a return air split between the last working place on a 
working section and where that split of air meets another split of air, 
or the location at which the split is used to ventilate seals or 
worked-out areas changes or adjustments shall be made at once to the 
ventilation system to reduce the concentration of methane in the return 
air to less than 1.0 percent.
    (2) When 1.5 percent or more methane is present in a return air 
split between the last working place on a working section and where 
that split of air meets another split of air, or the location where the 
split is used to ventilate seals or worked-out areas--
    (i) Everyone except those persons referred to in Sec. 104(c) of the 
Act shall be withdrawn from the affected area;
    (ii) Other than intrinsically safe AMS, equipment in the affected 
area shall be deenergized, electric power shall be disconnected at the 
power source, and other mechanized equipment shall be shut off; and
    (iii) No other work shall be permitted in the affected area until 
the methane concentration in the return air is less than 1.0 percent.
    (d) Return air split alternative. (1) The provisions of this 
paragraph apply if--
    (i) The quantity of air in the split ventilating the active 
workings is at least 27,000 cubic feet per minute in the last open 
crosscut or the quantity specified in the approved ventilation plan, 
whichever is greater;
    (ii) The methane content of the air in the split is continuously 
monitored during mining operations by an AMS that gives a visual and 
audible signal on the working section when the methane in the return 
air reaches 1.5 percent, and the methane content is monitored as 
specified in Sec. 75.351; and
    (iii) Rock dust is continuously applied with a mechanical duster to 
the return air course during coal production at a location in the air 
course immediately outby the most inby monitoring point.
    (2) When 1.5 percent or more methane is present in a return air 
split between a point in the return opposite the section loading point 
and where that split of air meets another split of air or where the 
split of air is used to ventilate seals or worked-out areas--
    (i) Changes or adjustments shall be made at once to the ventilation 
system to reduce the concentration of methane in the return air below 
1.5 percent;
    (ii) Everyone except those persons referred to in Sec. 104(c) of 
the Act shall be withdrawn from the affected area;
    (iii) Except for intrinsically safe AMS, equipment in the affected 
area shall be deenergized, electric power shall be disconnected at the 
power source, and other mechanized equipment shall be shut off; and
    (iv) No other work shall be permitted in the affected area until 
the methane concentration in the return air is less than 1.5 percent.
    (e) Bleeders and other return air courses. The concentration of 
methane in a bleeder split of air immediately before the air in the 
split joins another split of air, or in a return air course other than 
as described in paragraphs (c) and (d) of this section, shall not 
exceed 2.0 percent.

[[Page 9833]]



Sec. 75.324 Intentional changes in the ventilation system.

    (a) A person designated by the operator shall supervise any 
intentional change in ventilation that--
    (1) Alters the main air current or any split of the main air 
current in a manner that could materially affect the safety or health 
of persons in the mine; or
    (2) Affects section ventilation by 9,000 cubic feet per minute of 
air or more in bituminous or lignite mines, or 5,000 cubic feet per 
minute of air or more in anthracite mines.
    (b) Intentional changes shall be made only under the following 
conditions:
    (1) Electric power shall be removed from areas affected by the 
ventilation change and mechanized equipment in those areas shall be 
shut off before the ventilation change begins.
    (2) Only persons making the change in ventilation shall be in the 
mine.
    (3) Electric power shall not be restored to the areas affected by 
the ventilation change and mechanized equipment shall not be restarted 
until a certified person has examined these areas for methane 
accumulation and for oxygen deficiency and has determined that the 
areas are safe.


Sec. 75.325 Air quantity.

    (a)(1) In bituminous and lignite mines the quantity of air shall be 
at least 3,000 cubic feet per minute reaching each working face where 
coal is being cut, mined, drilled for blasting, or loaded. When a 
greater quantity is necessary to dilute, render harmless, and carry 
away flammable, explosive, noxious, and harmful gases, dusts, smoke, 
and fumes, this quantity shall be specified in the approved ventilation 
plan. A minimum air quantity may be required to be specified in the 
approved ventilation plan for other working places or working faces.
    (2) The quantity of air reaching the working face shall be 
determined at or near the face end of the line curtain, ventilation 
tubing, or other ventilation control device. If the curtain, tubing, or 
device extends beyond the last row of permanent roof supports, the 
quantity of air reaching the working face shall be determined behind 
the line curtain or in the ventilation tubing at or near the last row 
of permanent supports.
    (3) If machine mounted dust collectors or diffuser fans are used, 
the approved ventilation plan shall specify the operating volume of the 
dust collector or diffuser fan.
    (b) In bituminous and lignite mines, the quantity of air reaching 
the last open crosscut of each set of entries or rooms on each working 
section and the quantity of air reaching the intake end of a pillar 
line shall be at least 9,000 cubic feet per minute unless a greater 
quantity is required to be specified in the approved ventilation plan.
    (c) In longwall and shortwall mining systems--
    (1) The quantity of air shall be at least 30,000 cubic feet per 
minute reaching the working face of each longwall, unless the operator 
demonstrates that a lesser air quantity will maintain continual 
compliance with applicable methane and respirable dust standards. This 
lesser quantity shall be specified in the approved ventilation plan. A 
quantity greater than 30,000 cubic feet per minute may be required to 
be specified in the approved ventilation plan.
    (2) The velocity of air that will be provided to control methane 
and respirable dust below applicable standards on each longwall or 
shortwall and the locations where these velocities will be provided 
shall be specified in the approved ventilation plan. The locations 
specified shall be at least 50 feet but no more than 100 feet from the 
headgate and tailgate, respectively.
    (d) Ventilation shall be maintained during installation and removal 
of mechanized mining equipment. The approved ventilation plan shall 
specify the minimum quantity of air, the locations where this quantity 
will be provided and the ventilation controls required.
    (e) In anthracite mines, the quantity of air shall be as follows:
    (1) At least 1,500 cubic feet per minute reaching each working face 
where coal is being mined, unless a greater quantity is required to be 
specified in the approved ventilation plan.
    (2) At least 5,000 cubic feet per minute passing through the last 
open crosscut in each set of entries or rooms and at the intake end of 
any pillar line, unless a greater quantity is required to be specified 
in the approved ventilation plan.
    (3) When robbing areas where air currents cannot be controlled and 
air measurements cannot be obtained, the air shall have perceptible 
movement.


Sec. 75.326 Mean entry air velocity.

    In exhausting face ventilation systems, the mean entry air velocity 
shall be at least 60 feet per minute reaching each working face where 
coal is being cut, mined, drilled for blasting, or loaded, and to any 
other working places as required in the approved ventilation plan. A 
lower mean entry air velocity may be approved in the ventilation plan 
if the lower velocity will maintain methane and respirable dust 
concentrations below the applicable levels. Mean entry air velocity 
shall be determined at or near the inby end of the line curtain, 
ventilation tubing, or other face ventilation control devices.


Sec. 75.327 Air courses and trolley haulage systems.

    (a) In any mine opened on or after March 30, 1970, or in any new 
working section of a mine opened before that date, where trolley 
haulage systems are maintained and where trolley wires or trolley 
feeder wires are installed, an authorized representative of the 
Secretary shall require enough entries or rooms as intake air courses 
to limit the velocity of air currents in the haulageways to minimize 
the hazards of fires and dust explosions in the haulageways.
    (b) Unless the district manager approves a higher velocity, the 
velocity of the air current in the trolley haulage entries shall be 
limited to not more than 250 feet per minute. A higher air velocity may 
be required to limit the methane content in these haulage entries or 
elsewhere in the mine to less than 1.0 percent and provide an adequate 
supply of oxygen.


Sec. 75.330 Face ventilation control devices.

    (a) Brattice cloth, ventilation tubing and other face ventilation 
control devices shall be made of flame-resistant material approved by 
MSHA.
    (b)(1) Ventilation control devices shall be used to provide 
ventilation to dilute, render harmless, and to carry away flammable, 
explosive, noxious, and harmful gases, dusts, smoke, and fumes--
    (i) To each working face from which coal is being cut, mined, 
drilled for blasting, or loaded; and
    (ii) To any other working places as required by the approved 
ventilation plan.
    (2) These devices shall be installed at a distance no greater than 
10 feet from the area of deepest penetration to which any portion of 
the face has been advanced unless an alternative distance is specified 
and approved in the ventilation plan. Alternative distances specified 
shall be capable of maintaining concentrations of respirable dust, 
methane, and other harmful gases below the levels specified in the 
applicable sections of this chapter.
    (c) When the 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 shall cease 
until necessary repairs 

[[Page 9834]]
are made and adequate ventilation is restored.


Sec. 75.331 Auxiliary fans and tubing.

    (a) When auxiliary fans and tubing are used for face ventilation, 
each auxiliary fan shall be--
    (1) Permissible, if the fan is electrically operated;
    (2) Maintained in proper operating condition;
    (3) Deenergized or shut off when no one is present on the working 
section; and
    (4) Located and operated to avoid recirculation of air.
    (b) If a deficiency exists in any auxiliary fan system, the 
deficiency shall be corrected or the auxiliary fan shall be deenergized 
immediately.
    (c) If the air passing through an auxiliary fan or tubing contains 
1.0 percent or more methane, power to electrical equipment in the 
working place and to the auxiliary fan shall be deenergized, and other 
mechanized equipment in the working place shall be shut off until the 
methane concentration is reduced to less than 1.0 percent.
    (d) When an auxiliary fan is stopped--
    (1) Line brattice or other face ventilation control devices shall 
be used to maintain ventilation to affected faces; and
    (2) Electrical equipment in the affected working places shall be 
disconnected at the power source, and other mechanized equipment shall 
be shut off until ventilation to the working place is restored.


Sec. 75.332 Working sections and working places.

    (a)(1) 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.
    (2) When two or more sets of mining equipment are simultaneously 
engaged in cutting, mining, or loading coal or rock from working places 
within the same working section, each set of mining equipment shall be 
on a separate split of intake air.
    (3) For purposes of this section, a set of mining equipment 
includes a single loading machine, a single continuous mining machine, 
or a single longwall or shortwall mining machine.
    (b)(1) Air that has passed through any area that is not examined 
under Secs. 75.360, 75.361 or 75.364 of this subpart, or through an 
area where second mining has been done shall not be used to ventilate 
any working place. Second mining is intentional retreat mining where 
pillars have been wholly or partially removed, regardless of the amount 
of recovery obtained.
    (2) Air that has passed by any opening of any unsealed area that is 
not examined under Secs. 75.360, 75.361 or 75.364 of this subpart, 
shall not be used to ventilate any working place.


Sec. 75.333 Ventilation controls.

    (a) For purposes of this section, ``doors'' include any door 
frames.
    (b) Permanent stoppings or other permanent ventilation control 
devices constructed after November 15, 1992, shall be built and 
maintained--
    (1) Between intake and return air courses, except temporary 
controls may be used in rooms that are 600 feet or less from the 
centerline of the entry from which the room was developed including 
where continuous face haulage systems are used in such rooms. Unless 
otherwise approved in the ventilation plan, these stoppings or controls 
shall be maintained to and including the third connecting crosscut 
outby the working face;
    (2) To separate belt conveyor haulageways from return air courses, 
except where belt entries in areas of mines developed before March 30, 
1970, are used as return air courses;
    (3) To separate belt conveyor haulageways from intake air courses 
when the air in the intake air courses is used to provide air to active 
working places. Temporary ventilation controls may be used in rooms 
that are 600 feet or less from the centerline of the entry from which 
the rooms were developed including where continuous face haulage 
systems are used in such rooms. When continuous face haulage systems 
are used, permanent stoppings or other permanent ventilation control 
devices shall be built and maintained to the outby most point of travel 
of the dolly or 600 feet from the point of deepest penetration in the 
conveyor belt entry, whichever distance is closer to the point of 
deepest penetration, to separate the continuous haulage entry from the 
intake entries;
    (4) To separate the primary escapeway from belt and trolley haulage 
entries, as required by Sec. 75.380(g). For the purposes of 
Sec. 75.380(g), the loading point for a continuous haulage system shall 
be the outby most point of travel of the dolly or 600 feet from the 
point of deepest penetration, whichever distance is less; and
    (5) In return air courses to direct air into adjacent worked-out 
areas.
    (c) Personnel doors shall be constructed of noncombustible material 
and shall be of sufficient strength to serve their intended purpose of 
maintaining separation and permitting travel between air courses, and 
shall be installed as follows in permanent stoppings constructed after 
November 15, 1992:
    (1) The distance between personnel doors shall be no more than 300 
feet in seam heights below 48 inches and 600 feet in seam heights 48 
inches or higher.
    (2) The location of all personnel doors in stoppings along 
escapeways shall be clearly marked so that the doors may be easily 
identified by anyone traveling in the escapeway and in the entries on 
either side of the doors.
    (3) When not in use, personnel doors shall be closed.
    (d) Doors, other than personnel doors, constructed after November 
15, 1992, that are used in lieu of permanent stoppings or to control 
ventilation within an air course shall be:
    (1) Made of noncombustible material or coated on all accessible 
surfaces with flame-retardant material having a flame-spread index of 
25 or less, as tested under ASTM E162-87.
    (2) Of sufficient strength to serve their intended purpose of 
maintaining separation and permitting travel between or within air 
courses or entries.
    (3) Installed in pairs to form an airlock. When an airlock is used, 
one side of the airlock shall remain closed. When not in use, both 
sides shall be closed.
    (e)(1)(i) Except as provided in paragraphs (e)(2), (e)(3) and 
(e)(4) of this section all overcasts, undercasts, shaft partitions, 
permanent stoppings, and regulators, installed after March 11, 1997, 
shall be constructed in a traditionally accepted method and of 
materials that have been demonstrated to perform adequately or in a 
method and of materials that have been tested and shown to have a 
minimum strength 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 shall be designed to 
demonstrate the comparative strength of the proposed construction and a 
traditionally accepted in-mine control.
    (ii) All overcasts, undercasts, shaft partitions, permanent 
stoppings, and regulators, installed after November 15, 1992, shall be 
constructed of noncombustible material. Materials that are suitable for 
the construction of overcasts, undercasts, shaft partitions, permanent 
stoppings, and regulators include concrete, concrete block, brick, 
cinder block, tile, or steel. No ventilation controls installed after 

[[Page 9835]]
November 15, 1992, shall be constructed of aluminum.
    (2) In anthracite mines, permanent stoppings may be constructed of 
overlapping layers of hardwood mine boards, if the stoppings are a 
minimum 2 inches thick.
    (3) When timbers are used to create permanent stoppings in heaving 
or caving areas, the stoppings shall be coated on all accessible 
surfaces with a flame-retardant material having a flame-spread index of 
25 or less, as tested under ASTM E162-87, ``Surface Flammability of 
Materials Using a Radiant Heat Energy Source.''
    (4) In anthracite mines, doors and regulators may be constructed of 
overlapping layers of hardwood boards, if the doors, door frames, and 
regulators are a minimum 2 inches thick.
    (f) When sealants are applied to ventilation controls, the sealant 
shall have a flame-spread index of 25 or less under ASTM E162-87.
    (g) Before mining is discontinued in an entry or room that is 
advanced more than 20 feet from the inby rib, a crosscut shall be made 
or line brattice shall be installed and maintained to provide adequate 
ventilation. When conditions such as methane liberation warrant a 
distance less than 20 feet, the approved ventilation plan shall specify 
the location of such rooms or entries and the maximum distance they 
will be developed before a crosscut is made or line brattice is 
installed.
    (h) All permanent ventilation controls, including seals, shall be 
maintained to serve the purpose for which they were built.


Sec. 75.334 Worked-out areas and areas where pillars are being recovered.

    (a) Worked-out areas where no pillars have been recovered shall 
be--
    (1) Ventilated so that methane-air mixtures and other gases, dusts, 
and fumes from throughout the worked-out areas are continuously diluted 
and routed into a return air course or to the surface of the mine; or
    (2) Sealed.
    (b)(1) During pillar recovery a bleeder system shall be used to 
control the air passing through the area and to continuously dilute and 
move methane-air mixtures and other gases, dusts, and fumes from the 
worked-out area away from active workings and into a return air course 
or to the surface of the mine.
    (2) After pillar recovery a bleeder system shall be maintained to 
provide ventilation to the worked-out area, or the area shall be 
sealed.
    (c) The approved ventilation plan shall specify the following:
    (1) The design and use of bleeder systems;
    (2) The means to determine the effectiveness of bleeder systems;
    (3) The means for adequately maintaining bleeder entries free of 
obstructions such as roof falls and standing water; and
    (4) The location of ventilating devices such as regulators, 
stoppings and bleeder connectors used to control air movement through 
the worked-out area.
    (d) If the bleeder system used does not continuously dilute and 
move methane-air mixtures and other gases, dusts, and fumes away from 
worked-out areas into a return air course or to the surface of the 
mine, or it cannot be determined by examinations or evaluations under 
Sec. 75.364 that the bleeder system is working effectively, the worked-
out area shall be sealed.
    (e) Each mining system shall be designed so that each worked-out 
area can be sealed. The approved ventilation plan shall specify the 
location and the sequence of construction of proposed seals.
    (f) In place of the requirements of paragraphs (a) and (b) of this 
section, for mines with a demonstrated history of spontaneous 
combustion, or that are located in a coal seam determined to be 
susceptible to spontaneous combustion, the approved ventilation plan 
shall specify the following:
    (1) Measures to detect methane, carbon monoxide, and oxygen 
concentrations during and after pillar recovery, and in worked-out 
areas where no pillars have been recovered, to determine if the areas 
must be ventilated or sealed.
    (2) Actions that will be taken to protect miners from the hazards 
of spontaneous combustion.
    (3) 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.


Sec. 75.335 Construction of seals.

    (a)(1) Each seal constructed after November 15, 1992, shall be--
    (i) Constructed of solid concrete blocks at least 6 by 8 by 16 
inches, laid in a transverse pattern with mortar between all joints;
    (ii) Hitched into solid ribs to a depth of at least 4 inches and 
hitched at least 4 inches into the floor;
    (iii) At least 16 inches thick. When the thickness of the seal is 
less than 24 inches and the width is greater than 16 feet or the height 
is greater than 10 feet, a pilaster shall be interlocked near the 
center of the seal. The pilaster shall be at least 16 inches by 32 
inches; and
    (iv) Coated on all accessible surfaces with flame-retardant 
material that will minimize leakage and that has a flame-spread index 
of 25 or less, as tested under ASTM E162-87, ``Surface Flammability of 
Materials Using a Radiant Heat Energy Source.''
    (2) Alternative methods or materials may be used to create a seal 
if they can withstand a static horizontal pressure of 20 pounds per 
square inch provided the method of installation and the material used 
approved in the ventilation plan. If the alternative methods or 
materials include the use of timbers, the timbers also shall be coated 
on all accessible surfaces with flame-retardant material having a 
flame-spread index 25 or less, as tested under ASTM E162-87.
    (b) A sampling pipe or pipes shall be installed in each set of 
seals for a worked-out area. Each pipe shall--
    (1) Extend into the sealed area a sufficient distance (at least 15 
feet) to obtain a representative sample from behind the seal;
    (2) Be equipped with a cap or shut-off valve; and
    (3) Be installed with the sampling end of the pipe about 12 inches 
from the roof.
    (c)(1) A corrosion-resistant water pipe or pipes shall be installed 
in seals at the low points of the area being sealed and at all other 
locations necessary when water accumulation within the sealed area is 
possible; and
    (2) Each water pipe shall have a water trap installed on the outby 
side of the seal.


Sec. 75.340 Underground electrical installations.

    (a) Underground transformer stations, battery charging stations, 
substations, rectifiers, and water pumps shall be housed in 
noncombustible structures or areas or be equipped with a fire 
suppression system meeting the requirements of Sec. 75.1107-3 through 
Sec. 75.1107-16.
    (1) When a noncombustible structure or area is used, these 
installations shall be--
    (i) Ventilated with intake air that is coursed into a return air 
course or to the surface and that is not used to ventilate working 
places; or
    (ii) Ventilated with intake air that is monitored for carbon 
monoxide or smoke by an AMS installed and operated according to 
Sec. 75.351. Monitoring of intake air ventilating battery charging 
stations shall be done with sensors not affected by hydrogen; or
    (iii) Ventilated with intake air and equipped with sensors to 
monitor for heat and for carbon monoxide or smoke. Monitoring of intake 
air ventilating battery charging stations shall be done 

[[Page 9836]]
with sensors not affected by hydrogen. The sensors shall deenergize 
power to the installation, activate a visual and audible alarm located 
outside of and on the intake side of the enclosure, and activate doors 
that will automatically close when either of the following occurs:
    (A) The temperature in the noncombustible structure reaches 165 
deg.F; or
    (B) The carbon monoxide concentration reaches 10 parts per million 
above the ambient level for the area, or the optical density of smoke 
reaches 0.022 per meter. At least every 31 days, sensors installed to 
monitor for carbon monoxide shall be calibrated with a known 
concentration of carbon monoxide and air sufficient to activate the 
closing door, or each smoke sensor shall be tested to determine that it 
functions correctly.
    (2) When a fire suppression system is used, these installations 
shall be--
    (i) Ventilated with intake air that is coursed into a return air 
course or to the surface and that is not used to ventilate working 
places; or
    (ii) Ventilated with intake air that is monitored for carbon 
monoxide or smoke by an AMS installed and operated according to 
Sec. 75.351. Monitoring of intake air ventilating battery charging 
stations shall be done with sensors not affected by hydrogen.
    (b) This section does not apply to--
    (1) Rectifiers and power centers with transformers that are either 
dry-type or contain nonflammable liquid, if they are located at or near 
the section and are moved as the working section advances or retreats;
    (2) Submersible pumps;
    (3) Permissible pumps and associated permissible switchgear;
    (4) Pumps located on or near the section and that are moved as the 
working section advances or retreats;
    (5) Pumps installed in anthracite mines; and
    (6) Small portable pumps.


Sec. 75.341 Direct-fired intake air heaters.

    (a) If any system used to heat intake air malfunctions, the heaters 
affected shall switch off automatically.
    (b) Thermal overload devices shall protect the blower motor from 
overheating.
    (c) The fuel supply shall turn off automatically if a flame-out 
occurs.
    (d) Each heater shall be located or guarded to prevent contact by 
persons and shall be equipped with a screen at the inlet to prevent 
combustible materials from passing over the burner units.
    (e) If intake air heaters use liquefied fuel systems--
    (1) Hydrostatic relief valves installed on vaporizers and on 
storage tanks shall be vented; and
    (2) Fuel storage tanks shall be located or protected to prevent 
fuel from leaking into the mine.
    (f) Following any period of 8 hours or more during which a heater 
does not operate, the heater and its associated components shall be 
examined within its first hour of operation. Additionally, each heater 
and its components shall be examined at least once each shift that the 
heater operates. The examination shall include measurement of the 
carbon monoxide concentration at the bottom of each shaft, slope, or in 
the drift opening where air is being heated. The measurements shall be 
taken by a person designated by the operator or by a carbon monoxide 
sensor that is calibrated with a known concentration of carbon monoxide 
and air at least once every 31 days. When the carbon monoxide 
concentration at this location reaches 50 parts per million, the heater 
causing the elevated carbon monoxide level shall be shut down.


Sec. 75.342 Methane monitors.

    (a)(1) MSHA approved methane monitors shall be installed on all 
face cutting machines, continuous miners, longwall face equipment, 
loading machines, and other mechanized equipment used to extract or 
load coal within the working place.
    (2) The sensing device for methane monitors on longwall shearing 
machines shall be installed at the return air end of the longwall face. 
An additional sensing device also shall be installed on the longwall 
shearing machine, downwind and as close to the cutting head as 
practicable. An alternative location or locations for the sensing 
device required on the longwall shearing machine may be approved in the 
ventilation plan.
    (3) The sensing devices of methane monitors shall be installed as 
close to the working face as practicable.
    (4) Methane monitors shall be maintained in permissible and proper 
operating condition and shall be calibrated with a known air-methane 
mixture at least once every 31 days. To assure that methane monitors 
are properly maintained and calibrated, the operator shall:
    (i) Use persons properly trained in the maintenance, calibration, 
and permissibility of methane monitors to calibrate and maintain the 
devices.
    (ii) Maintain a record of all calibration tests of methane 
monitors. Records shall be maintained in a secure book that is not 
susceptible to alteration or electronically in a computer system so as 
to be secure and not susceptible to alteration.
    (iii) Retain the record of calibration tests for 1 year from the 
date of the test. Records shall be retained at a surface location at 
the mine and made available for inspection by authorized 
representatives of the Secretary and the representative of miners.
    (b)(1) When the methane concentration at any methane monitor 
reaches 1.0 percent the monitor shall give a warning signal.
    (2) The warning signal device of the methane monitor shall be 
visible to a person who can deenergize the equipment on which the 
monitor is mounted.
    (c) The methane monitor shall automatically deenergize the machine 
on which it is mounted when--
    (1) The methane concentration at any methane monitor reaches 2.0 
percent; or
    (2) The monitor is not operating properly.


Sec. 75.343 Underground shops.

    (a) Underground shops shall be equipped with an automatic fire 
suppression system meeting the requirements of Sec. 75.1107-3 through 
Sec. 75.1107-16, or be enclosed in a noncombustible structure or area.
    (b) Underground shops shall be ventilated with intake air that is 
coursed directly into a return air course.


Sec. 75.344 Compressors.

    (a) Except compressors that are components of equipment such as 
locomotives and rock dusting machines and compressors of less than 5 
horsepower, electrical compressors including those that may start 
automatically shall be:
    (1) Continuously attended by a person designated by the operator 
who can see the compressor at all times during its operation. Any 
designated person attending the compressor shall be capable of 
activating the fire suppression system and deenergizing or shutting-off 
the compressor in the event of a fire; or,
    (2) Enclosed in a noncombustible structure or area which is 
ventilated by intake air coursed directly into a return air course or 
to the surface and equipped with sensors to monitor for heat and for 
carbon monoxide or smoke. The sensors shall deenergize power to the 
compressor, activate a visual and audible alarm located outside of and 
on the intake side of the enclosure, and activate doors to 
automatically enclose the noncombustible structure or area when either 
of the following occurs:
    (i) The temperature in the noncombustible structure or area reaches 
165  deg.F. 

[[Page 9837]]

    (ii) The carbon monoxide concentration reaches 10 parts per million 
above the ambient level for the area, or the optical density of smoke 
reaches 0.022 per meter. At least once every 31 days, sensors installed 
to monitor for carbon monoxide shall be calibrated with a known 
concentration of carbon monoxide and air sufficient to activate the 
closing door, and each smoke sensor shall be tested to determine that 
it functions correctly.
    (b) Compressors, except those exempted in paragraph (a), shall be 
equipped with a heat activated fire suppression system meeting the 
requirements of 75.1107-3 through 75.1107-16.
    (c) Two portable fire extinguishers or one extinguisher having at 
least twice the minimum capacity specified for a portable fire 
extinguisher in Sec. 75.1100-1(e) shall be provided for each 
compressor.
    (d) In addition to electrical compressors, this section shall apply 
to diesel compressors.
    (e) Notwithstanding the requirements of Sec. 75.1107-4, upon 
activation of any fire suppression system used under paragraph (b) of 
this section, the compressor shall be automatically deenergized or 
automatically shut off.


Sec. 75.350 Air courses and belt haulage entries.

    In any coal mine opened after March 30, 1970, the entries used as 
intake and return air courses shall be separated from belt haulage 
entries, and each operator of such mine shall limit the velocity of the 
air coursed through belt haulage entries to the amount necessary to 
provide an adequate supply of oxygen in such entries, and to insure 
that the air therein shall contain less than 1.0 volume per centum of 
methane, and such air shall not be used to ventilate active working 
places. Whenever an authorized representative of the Secretary finds, 
in the case of any coal mine opened on or prior to March 30, 1970, that 
has been developed with more than two entries, that the conditions in 
the entries, other than belt haulage entries, are such as to permit 
adequately the coursing of intake or return air through such entries:
    (a) The belt haulage entries shall not be used to ventilate, unless 
such entries are necessary to ventilate, active working places, and
    (b) When the belt haulage entries are not necessary to ventilate 
the active working places, the operator of such mine shall limit the 
velocity of the air coursed through the belt haulage entries to the 
amount necessary to provide an adequate supply of oxygen in such 
entries, and to assure that air therein shall contain less than 1.0 
volume per centum of methane.


Sec. 75.351 Atmospheric monitoring system (AMS).

    (a) Minimum requirements. An AMS shall consist of sensors to 
monitor the mine atmosphere and instruments at a surface location 
designated by the operator to receive information from the monitoring 
sensors. Each AMS installed in accordance with Secs. 75.323(d)(1)(ii), 
75.340(a)(2) and 75.362(f) shall do the following:
    (1) Monitor for circuit continuity and sensor function, and 
identify at the designated surface location any activated or 
malfunctioning sensor.
    (2) Signal a designated surface location at the mine when any 
interruption of circuit continuity occurs or any sensor malfunctions.
    (3) Signal affected working sections and the designated surface 
location when--
    (i) The carbon monoxide concentration at any carbon monoxide sensor 
reaches 5 parts per million above the established ambient level for 
that area; or
    (ii) The methane concentration at any methane monitoring station 
exceeds the maximum allowable concentration as specified for that 
location in Sec. 75.323.
    (4) Activate alarms at a designated surface location and affected 
working sections when the carbon monoxide concentration at any carbon 
monoxide sensor reaches 10 parts per million above the established 
ambient level for the area or when the optical density of smoke at any 
smoke sensor reaches 0.05 per meter.
    (b) Return splits. (1) If used to monitor return air splits under 
Sec. 75.362(f), AMS sensors shall monitor the mine atmosphere for 
percentage of methane in each return split of air from each working 
section between the last working place, or longwall or shortwall face, 
ventilated by that air split and the junction of that return air split 
with another air split, seal, or worked-out area. If auxiliary fans and 
tubing are used, the sensor also shall be located outby the auxiliary 
fan discharge.
    (2) If used to monitor air splits under Sec. 75.323(d)(1)(ii), AMS 
sensors shall monitor the mine atmosphere at the following locations:
    (i) In the return air course opposite the section loading point or, 
if auxiliary fans and tubing are used, in the return air course outby 
the auxiliary fans and a point opposite the section loading point.
    (ii) Immediately inby the location where the split of air meets 
another split of air, or inby the location where the split of air is 
used to ventilate seals or worked-out areas.
    (c) Electrical installations. If used to monitor the intake air 
ventilating underground transformer stations, battery charging 
stations, substations, rectifiers, or water pumps under 
Sec. 75.340(a)(2), at least one sensor shall be installed to monitor 
the mine atmosphere for carbon monoxide or smoke at least 50 feet and 
no more than 100 feet downstream in the direction of air flow.
    (d) Signals and alarms. (1) A person designated by the operator 
shall be at a surface location where the signals and alarms from the 
AMS can always be seen or heard while anyone is underground. This 
person shall have access to two-way communication with working sections 
and with other identifiable duty stations underground. A mine map 
showing the underground monitoring system shall be posted at the 
surface location.
    (2) If a signal from any AMS sensor is activated, the monitor 
producing the signal shall be identified, an examination shall be made 
to determine the cause of the activation, and appropriate action shall 
be taken.
    (e) Sensors. (1) Each carbon monoxide sensor shall be capable of 
detecting carbon monoxide in air at a level of <plus-minus>1 part per 
million throughout the operating range.
    (2) Each methane sensor shall be capable of detecting 1.0 percent 
methane in air with an accuracy of <plus-minus>0.2 percent methane.
    (3) Each smoke sensor shall be capable of detecting the optical 
density of smoke with an accuracy of <plus-minus>0.005 per meter.
    (f) Testing and calibration. At least once every 31 days--
    (1) Each carbon monoxide sensor shall be calibrated with a known 
concentration of carbon monoxide and air sufficient to activate an 
alarm;
    (2) Each smoke sensor shall be functionally tested;
    (3) Each methane sensor shall be calibrated with a known methane-
air mixture; and
    (4) Each oxygen sensor shall be calibrated with air having a known 
oxygen concentration.
    (g) Intrinsic Safety. Components of AMS installed in areas where 
permissible equipment is required shall be intrinsically safe.
    (h) Recordkeeping. If a signal device or alarm is activated, a 
record shall be made of the date, time, type of sensor, and the reason 
for its activation. Also the maximum concentration detected at 

[[Page 9838]]
the sensor producing the signal shall be recorded.
    (i) Retention period. Records shall be retained for at least 1 year 
at a surface location at the mine and made available for inspection by 
authorized representatives of the Secretary and representatives of 
miners.


Sec. 75.352 Return air courses.

    Entries used as return air courses shall be separated from belt 
haulage entries by permanent ventilation controls.


Sec. 75.360 Preshift examination.

    (a)(1) Except as provided in paragraph (a)(2) of this section, a 
certified person designated by the operator shall make a preshift 
examination within 3 hours preceding the beginning of any 8-hour 
interval during which any person is scheduled to work or travel 
underground. The operator shall establish the 8-hour intervals of time 
subject to the required preshift examinations. No person other than 
certified examiners may enter or remain in any underground area unless 
a preshift examination has been completed for the established 8-hour 
period.
    (2) Preshift examinations of areas where pumpers are scheduled to 
work or travel shall not be required prior to the pumper entering the 
areas if the pumper is a certified person and the pumper conducts an 
examination for hazardous conditions, tests for methane and oxygen 
deficiency and determines if the air is moving in its proper direction 
in the area where the pumper works or travels. The examination of the 
area must be completed before the pumper performs any other work. A 
record of all hazardous conditions found by the pumper shall be made 
and retained in accordance with Sec. 75.363.
    (b) The person conducting the preshift examination shall examine 
for hazardous conditions, test for methane and oxygen deficiency, and 
determine if the air is moving in its proper direction at the following 
locations:
    (1) Roadways, travelways and track haulageways where persons are 
scheduled, prior to the beginning of the preshift examination, to work 
or travel during the oncoming shift.
    (2) Belt conveyors that will be used to transport persons during 
the oncoming shift and the entries in which these belt conveyors are 
located.
    (3) Working sections and areas where mechanized mining equipment is 
being installed or removed, if anyone is scheduled to work on the 
section or in the area during the oncoming shift. The scope of the 
examination shall include the working places, approaches to worked-out 
areas and ventilation controls on these sections and in these areas, 
and the examination shall include tests of the roof, face and rib 
conditions on these sections and in these areas.
    (4) Approaches to worked-out areas along intake air courses and at 
the entries used to carry air into worked-out areas if the intake air 
passing the approaches is used to ventilate working sections where 
anyone is scheduled to work during the oncoming shift. The examination 
of the approaches to the worked-out areas shall be made in the intake 
air course immediately inby and outby each entry used to carry air into 
the worked-out area. An examination of the entries used to carry air 
into the worked-out areas shall be conducted at a point immediately 
inby the intersection of each entry with the intake air course.
    (5) Seals along intake air courses where intake air passes by a 
seal to ventilate working sections where anyone is scheduled to work 
during the oncoming shift.
    (6)(i) Entries and rooms developed after November 15, 1992, and 
developed more than 2 crosscuts off an intake air course without 
permanent ventilation controls where intake air passes through or by 
these entries or rooms to reach a working section where anyone is 
scheduled to work during the oncoming shift; and,
    (ii) Entries and rooms developed after November 15, 1992, and 
driven more than 20 feet off an intake air course without a crosscut 
and without permanent ventilation controls where intake air passes 
through or by these entries or rooms to reach a working section where 
anyone is scheduled to work during the oncoming shift.
    (7) Where unattended diesel equipment is to operate or areas where 
trolley wires or trolley feeder wires are to be or will remain 
energized during the oncoming shift.
    (8) High spots along intake air courses where methane is likely to 
accumulate, if equipment will be operated in the area during the shift.
    (9) Underground electrical installations referred to in 
Sec. 75.340(a), except those pumps listed in Sec. 75.340 (b)(2) through 
(b)(6), and areas where compressors subject to Sec. 75.344 are 
installed if the electrical installation or compressor is or will be 
energized during the shift.
    (10) Other areas where work or travel during the oncoming shift is 
scheduled prior to the beginning of the preshift examination.
    (c) The person conducting the preshift examination shall determine 
the volume of air entering each of the following areas if anyone is 
scheduled to work in the areas during the oncoming shift:
    (1) In the last open crosscut of each set of entries or rooms on 
each working section and areas where mechanized mining equipment is 
being installed or removed. The last open crosscut is the crosscut in 
the line of pillars containing the permanent stoppings that separate 
the intake air courses and the return air courses.
    (2) On each longwall or shortwall in the intake entry or entries at 
the intake end of the longwall or shortwall face immediately outby the 
face and the velocity of air at each end of the face at the locations 
specified in the approved ventilation plan.
    (3) At the intake end of any pillar line--
    (i) If a single split of air is used, in the intake entry furthest 
from the return air course, immediately outby the first open crosscut 
outby the line of pillars being mined; or
    (ii) If a split system is used, in the intake entries of each split 
immediately inby the split point.
    (d) The district manager may require the certified person to 
examine other areas of the mine or examine for other hazards during the 
preshift examination.
    (e) Certification. At each working place examined, the person doing 
the preshift examination shall certify by initials, date, and the time, 
that the examination was made. In areas required to be examined outby a 
working section, the certified person shall certify by initials, date, 
and the time at enough locations to show that the entire area has been 
examined.
    (f) Recordkeeping. A record of the results of each preshift 
examination, including a record of hazardous conditions and their 
locations found by the examiner during each examination and of the 
results and locations of air and methane measurements, shall be made on 
the surface before any persons, other than certified persons conducting 
examinations required by this subpart, enter any underground area of 
the mine. The results of methane tests shall be recorded as the 
percentage of methane measured by the examiner. The record shall be 
made by the certified person who made the examination or by a person 
designated by the operator. If the record is made by someone other than 
the examiner, the examiner shall verify the record by initials and date 
by or at the end of the shift for which the examination was made. A 
record shall also be made by a certified person of the action taken to 
correct hazardous conditions found during the preshift 

[[Page 9839]]
examination. All preshift and corrective action records shall be 
countersigned by the mine foreman or equivalent mine official by the 
end of the mine foreman's or equivalent mine official's next regularly 
scheduled working shift. The records required by this section shall be 
made in a secure book that is not susceptible to alteration or 
electronically in a computer system so as to be secure and not 
susceptible to alteration.
    (g) Retention period. Records shall be retained at a surface 
location at the mine for at least 1 year and shall be made available 
for inspection by authorized representatives of the Secretary and the 
representative of miners.


Sec. 75.361 Supplemental examination.

    (a) Except for certified persons conducting examinations required 
by this subpart, within 3 hours before anyone enters an area in which a 
preshift examination has not been made for that shift, a certified 
person shall examine the area for hazardous conditions, determine 
whether the air is traveling in its proper direction and at its normal 
volume, and test for methane and oxygen deficiency.
    (b) Certification. At each working place examined, the person 
making the supplemental examination shall certify by initials, date, 
and the time, that the examination was made. In areas required to be 
examined outby a working section, the certified person shall certify by 
initials, date, and the time at enough locations to show that the 
entire area has been examined.


Sec. 75.362 On-shift examination.

    (a) (1) At least once during each shift, or more often if necessary 
for safety, a certified person designated by the operator shall conduct 
an on-shift examination of each section where anyone is assigned to 
work during the shift and any area where mechanized mining equipment is 
being installed or removed during the shift. The certified person shall 
check for hazardous conditions, test for methane and oxygen deficiency, 
and determine if the air is moving in its proper direction.
    (2) A person designated by the operator shall conduct an 
examination to assure compliance with the respirable dust control 
parameters specified in the mine ventilation plan. In those instances 
when a shift change is accomplished without an interruption in 
production on a section, the examination shall be made anytime within 1 
hour of the shift change. In those instances when there is an 
interruption in production during the shift change, the examination 
shall be made before production begins on a section. Deficiencies in 
dust controls shall be corrected before production begins or resumes. 
The examination shall include air quantities and velocities, water 
pressures and flow rates, excessive leakage in the water delivery 
system, water spray numbers and orientations, section ventilation and 
control device placement, and any other dust suppression measures 
required by the ventilation plan. Additional measurements of the air 
velocity and quantity, water pressure and flow rates are not required 
if continuous monitoring of these controls is used and indicates that 
the dust controls are functioning properly.
    (b) During each shift that coal is produced, a certified person 
shall examine for hazardous conditions along each belt conveyor 
haulageway where a belt conveyor is operated. This examination may be 
conducted at the same time as the preshift examination of belt 
conveyors and belt conveyor haulageways, if the examination is 
conducted within 3 hours before the oncoming shift.
    (c) Persons conducting the on-shift examination shall determine at 
the following locations:
    (1) The volume of air in the last open crosscut of each set of 
entries or rooms on each section and areas where mechanized mining 
equipment is being installed or removed. The last open crosscut is the 
crosscut in the line of pillars containing the permanent stoppings that 
separate the intake air courses and the return air courses.
    (2) The volume of air on a longwall or shortwall, including areas 
where longwall or shortwall equipment is being installed or removed, in 
the intake entry or entries at the intake end of the longwall or 
shortwall.
    (3) The velocity of air at each end of the longwall or shortwall 
face at the locations specified in the approved ventilation plan.
    (4) The volume of air at the intake end of any pillar line--
    (i) Where a single split of air is used in the intake entry 
furthest from the return air course immediately outby the first open 
crosscut outby the line of pillars being mined; or
    (ii) Where a split system is used in the intake entries of each 
split immediately inby the split point.
    (d) (1) A qualified person shall make tests for methane--
    (i) At the start of each shift at each working place before 
electrically operated equipment is energized; and
    (ii) Immediately before equipment is energized, taken into, or 
operated in a working place; and
    (iii) At 20-minute intervals, or more often if required in the 
approved ventilation plan at specific locations, during the operation 
of equipment in the working place.
    (2) These methane tests shall be made at the face from under 
permanent roof support, using extendable probes or other acceptable 
means. When longwall or shortwall mining systems are used, these 
methane tests shall be made at the shearer, the plow, or the cutting 
head. When mining has been stopped for more than 20 minutes, methane 
tests shall be conducted prior to the start up of equipment.
    (e) If auxiliary fans and tubing are used, they shall be inspected 
frequently.
    (f) During each shift that coal is produced and at intervals not 
exceeding 4 hours, tests for methane shall be made by a certified 
person or by an atmospheric monitoring system (AMS) in each return 
split of air from each working section between the last working place, 
or longwall or shortwall face, ventilated by that split of air and the 
junction of the return air split with another air split, seal, or 
worked-out area. If auxiliary fans and tubing are used, the tests shall 
be made at a location outby the auxiliary fan discharge.
    (g) Certification. (1) The person conducting the on-shift 
examination in belt haulage entries shall certify by initials, date, 
and time that the examination was made. The certified person shall 
certify by initials, date, and the time at enough locations to show 
that the entire area has been examined.
    (2) The person directing the on-shift examination to assure 
compliance with the respirable dust control parameters specified in the 
mine ventilation plan shall certify by initials, date, and time that 
the examination was made.


Sec. 75.363 Hazardous conditions; posting, correcting and recording.

    (a) Any hazardous condition found by the mine foreman or equivalent 
mine official, assistant mine foreman or equivalent mine official, or 
other certified persons designated by the operator for the purposes of 
conducting examinations under this subpart D, shall be posted with a 
conspicuous danger sign where anyone entering the areas would pass. A 
hazardous condition, other than one detected during a preshift 
examination or an examination conducted following a fan stoppage and 
restart under Sec. 75.313(d)(1)(i), shall be corrected immediately or 
the area shall remain posted until the hazardous condition is 
corrected. If the condition creates an imminent danger, everyone except 
those persons referred to in 

[[Page 9840]]
section 104(c) of the Act shall be withdrawn from the area affected to 
a safe area until the hazardous condition is corrected. Only persons 
designated by the operator to correct or evaluate the condition may 
enter the posted area.
    (b) A record shall be made of any hazardous condition found. This 
record shall be kept in a book maintained for this purpose on the 
surface at the mine. The record shall be made by the completion of the 
shift on which the hazardous condition is found and shall include the 
nature and location of the hazardous condition and the corrective 
action taken. This record shall not be required for shifts when no 
hazardous conditions are found or for hazardous conditions found during 
the preshift or weekly examinations inasmuch as these examinations have 
separate recordkeeping requirements.
    (c) The record shall be made by the certified person who conducted 
the examination or a person designated by the operator. If made by a 
person other than the certified person, the certified person shall 
verify the record by initials and date by or at the end of the shift 
for which the examination was made. Records shall be countersigned by 
the mine foreman or equivalent mine official by the end of the mine 
foreman's or equivalent mine official's next regularly scheduled 
working shift. The record shall be made in a secure book that is not 
susceptible to alteration or electronically in a computer system so as 
to be secure and not susceptible to alteration.
    (d) Retention period. Records shall be retained at a surface 
location at the mine for at least 1 year and shall be made available 
for inspection by authorized representatives of the Secretary and the 
representative of miners.


Sec. 75.364 Weekly examination.

    (a) Worked-out areas. (1) At least every 7 days, a certified person 
shall examine unsealed worked-out areas where no pillars have been 
recovered by traveling to the area of deepest penetration; measuring 
methane and oxygen concentrations and air quantities and making tests 
to determine if the air is moving in the proper direction in the area. 
The locations of measurement points where tests and measurements will 
be performed shall be included in the mine ventilation plan and shall 
be adequate in number and location to assure ventilation and air 
quality in the area. Air quantity measurements shall also be made where 
the air enters and leaves the worked-out area. An alternative method of 
evaluating the ventilation of the area may be approved in the 
ventilation plan.
    (2) At least every 7 days, a certified person shall evaluate the 
effectiveness of bleeder systems required by Sec. 75.334 as follows:
    (i) Measurements of methane and oxygen concentrations and air 
quantity and a test to determine if the air is moving in its proper 
direction shall be made where air enters the worked-out area.
    (ii) Measurements of methane and oxygen concentrations and air 
quantity and a test to determine if the air is moving in the proper 
direction shall be made immediately before the air enters a return 
split of air.
    (iii) At least one entry of each set of bleeder entries used as 
part of a bleeder system under Sec. 75.334 shall be traveled in its 
entirety. Measurements of methane and oxygen concentrations and air 
quantities and a test to determine if the air is moving in the proper 
direction shall be made at the measurement point locations specified in 
the mine ventilation plan to determine the effectiveness of the bleeder 
system.
    (iv) In lieu of the requirements of paragraphs (a)(2)(i) and (iii) 
of this section, an alternative method of evaluation may be specified 
in the ventilation plan provided the alternative method results in 
proper evaluation of the effectiveness of the bleeder system.
    (b) Hazardous conditions. At least every 7 days, an examination for 
hazardous conditions at the following locations shall be made by a 
certified person designated by the operator:
    (1) In at least one entry of each intake air course, in its 
entirety, so that the entire air course is traveled.
    (2) In at least one entry of each return air course, in its 
entirety, so that the entire air course is traveled.
    (3) In each longwall or shortwall travelway in its entirety, so 
that the entire travelway is traveled.
    (4) At each seal along return and bleeder air courses and at each 
seal along intake air courses not examined under Sec. 75.360(b)(5).
    (5) In each escapeway so that the entire escapeway is traveled.
    (6) On each working section not examined under Sec. 75.360(b)(3) 
during the previous 7 days.
    (7) At each water pump not examined during a preshift examination 
conducted during the previous 7 days.
    (c) Measurements and tests. At least every 7 days, a certified 
person shall--
    (1) Determine the volume of air entering the main intakes and in 
each intake split;
    (2) Determine the volume of air and test for methane in the last 
open crosscut in any pair or set of developing entries or rooms, in the 
return of each split of air immediately before it enters the main 
returns, and where the air leaves the main returns; and
    (3) Test for methane in the return entry nearest each set of seals 
immediately after the air passes the seals.
    (d) Hazardous conditions shall be corrected immediately. If the 
condition creates an imminent danger, everyone except those persons 
referred to in Sec. 104(c) of the Act shall be withdrawn from the area 
affected to a safe area until the hazardous condition is corrected.
    (e) The weekly examination may be conducted at the same time as the 
preshift or on-shift examinations.
    (f) (1) The weekly examination is not required during any 7 day 
period in which no one enters any underground area of the mine.
    (2) Except for certified persons required to make examinations, no 
one shall enter any underground area of the mine if a weekly 
examination has not been completed within the previous 7 days.
    (g) Certification. The person making the weekly examinations shall 
certify by initials, date, and the time that the examination was made. 
Certifications and times shall appear at enough locations to show that 
the entire area has been examined.
    (h) Recordkeeping. At the completion of any shift during which a 
portion of a weekly examination is conducted, a record of the results 
of each weekly examination, including a record of hazardous conditions 
found during each examination and their locations, the corrective 
action taken, and the results and location of air and methane 
measurements, shall be made. The results of methane tests shall be 
recorded as the percentage of methane measured by the examiner. The 
record shall be made by the person making the examination or a person 
designated by the operator. If made by a person other than the 
examiner, the examiner shall verify the record by the initials and date 
by or at the end of the shift for which the examination was made. The 
record shall be countersigned by the mine foreman or equivalent mine 
official by the end of the mine foreman's or equivalent mine official's 
next regularly scheduled working shift. The records required by this 
section shall be made in a secure book that is not susceptible to 
alteration or electronically in a computer system so as to be secure 
and not susceptible to alteration.
    (i) Retention period. Records shall be retained at a surface 
location at the mine for at least 1 year and shall be made available 
for inspection by authorized 

[[Page 9841]]
representatives of the Secretary and the representative of miners.


Sec. 75.370 Mine ventilation plan; submission and approval.

    (a) (1) The operator shall develop and follow a ventilation plan 
approved by the district manager. The plan shall be designed to control 
methane and respirable dust and shall be suitable to the conditions and 
mining system at the mine. The ventilation plan shall consist of two 
parts, the plan content as prescribed in Sec. 75.371 and the 
ventilation map with information as prescribed in Sec. 75.372. Only 
that portion of the map which contains information required under 
Sec. 75.371 will be subject to approval by the district manager.
    (2) The proposed ventilation plan and any revision to the plan 
shall be submitted in writing to the district manager. When revisions 
to a ventilation plan are proposed, only the revised pages, maps, or 
sketches of the plan need to be submitted. When required in writing by 
the district manager, the operator shall submit a fully revised plan by 
consolidating the plan and all revisions in an orderly manner and by 
deleting all outdated material.
    (3) (i) The mine operator shall notify the representative of miners 
at least 5 days prior to submission of a mine ventilation plan and any 
revision to a mine ventilation plan. If requested, the mine operator 
shall provide a copy to the representative of miners at the time of 
notification. In the event of a situation requiring immediate action on 
a plan revision, notification of the revision shall be given, and if 
requested, a copy of the revision shall be provided, to the 
representative of miners by the operator at the time of submittal;
    (ii) A copy of the proposed ventilation plan, and a copy of any 
proposed revision, submitted for approval shall be made available for 
inspection by the representative of miners; and
    (iii) A copy of the proposed ventilation plan, and a copy of any 
proposed revision, submitted for approval shall be posted on the mine 
bulletin board at the time of submittal. The proposed plan or proposed 
revision shall remain posted until it is approved, withdrawn or denied.
    (b) Following receipt of the proposed plan or proposed revision, 
the representative of miners may submit timely comments to the district 
manager, in writing, for consideration during the review process. A 
copy of these comments shall also be provided to the operator by the 
district manager upon request.
    (c) (1) The district manager will notify the operator in writing of 
the approval or denial of approval of a proposed ventilation plan or 
proposed revision. A copy of this notification will be sent to the 
representative of miners by the district manager.
    (2) If the district manager denies approval of a proposed plan or 
revision, the deficiencies of the plan or revision shall be specified 
in writing and the operator will be provided an opportunity to discuss 
the deficiencies with the district manager.
    (d) No proposed ventilation plan shall be implemented before it is 
approved by the district manager. Any intentional change to the 
ventilation system that alters the main air current or any split of the 
main air current in a manner that could materially affect the safety 
and health of the miners, or any change to the information required in 
Sec. 75.371 shall be submitted to and approved by the district manager 
before implementation.
    (e) Before implementing an approved ventilation plan or a revision 
to a ventilation plan, persons affected by the revision shall be 
instructed by the operator in its provisions.
    (f) The approved ventilation plan and any revisions shall be--
    (1) Provided upon request to the representative of miners by the 
operator following notification of approval;
    (2) Made available for inspection by the representative of miners; 
and
    (3) Posted on the mine bulletin board within 1 working day 
following notification of approval. The approved plan and revisions 
shall remain posted on the bulletin board for the period that they are 
in effect.
    (g) The ventilation plan for each mine shall be reviewed every 6 
months by an authorized representative of the Secretary to assure that 
it is suitable to current conditions in the mine.


Sec. 75.371 Mine ventilation plan; contents.

    The mine ventilation plan shall contain the information described 
below and any additional provisions required by the district manager:
    (a) The mine name, company name, mine identification number, and 
the name of the individual submitting the plan information.
    (b) Planned main mine fan stoppages, other than those scheduled for 
testing, maintenance or adjustment, including procedures to be followed 
during these stoppages and subsequent restarts (see Sec. 75.311(a)) and 
the type of device to be used for monitoring main mine fan pressure, if 
other than a pressure recording device (see 75.310(a)(4)).
    (c) Methods of protecting main mine fans and associated components 
from the forces of an underground explosion if a 15-foot offset from 
the nearest side of the mine opening is not provided (see 
Sec. 75.310(a)(6)); and the methods of protecting main mine fans and 
intake air openings if combustible material will be within 100 feet of 
the area surrounding the fan or these openings (see Sec. 75.311(f)).
    (d) Persons that will be permitted to enter the mine, the work 
these persons will do while in the mine, and electric power circuits 
that will be energized when a back-up fan system is used that does not 
provide the ventilating quantity provided by the main mine fan (see 
Sec. 75.311(c)).
    (e) The locations and operating conditions of booster fans 
installed in anthracite mines (see Sec. 75.302).
    (f) Section and face ventilation systems used, including drawings 
illustrating how each system is used, and a description of each 
different dust suppression system used on equipment on working 
sections.
    (g) Locations where the air quantities must be greater than 3,000 
cubic feet per minute (see Sec. 75.325(a)(1)).
    (h) In anthracite mines, locations where the air quantities must be 
greater than 1,500 cubic feet per minute (see Sec. 75.325(e)(1)).
    (i) Working places and working faces other than those where coal is 
being cut, mined, drilled for blasting or loaded, where a minimum air 
quantity will be maintained, and the air quantity at those locations 
(see Sec. 75.325(a)(1)).
    (j) The operating volume of machine mounted dust collectors or 
diffuser fans, if used (see Sec. 75.325(a)(3)).
    (k) The minimum mean entry air velocity in exhausting face 
ventilation systems where coal is being cut, mined, drilled for 
blasting, or loaded, if the velocity will be less than 60 feet per 
minute. Other working places where coal is not being cut, mined, 
drilled for blasting or loaded, where at least 60 feet per minute or 
some other minimum mean entry air velocity will be maintained (see 
Sec. 75.326).
    (l) The maximum distance if greater than 10 feet from each working 
face at which face ventilation control devices will be installed (see 
Sec. 75.330(b)(2)). The working places other than those where coal is 
being cut, mined, drilled for blasting or loaded, where face 
ventilation control devices will be used (see Sec. 75.330(b)(1)(ii).
    (m) The volume of air required in the last open crosscut or the 
quantity of air reaching the pillar line if greater than 9,000 cubic 
feet per minute (see Sec. 75.325(b)). 

[[Page 9842]]

    (n) In anthracite mines, the volume of air required in the last 
open crosscut or the quantity of air reaching the pillar line if 
greater than 5,000 cubic feet per minute (see Sec. 75.325(e)(2)).
    (o) Locations where separations of intake and return air courses 
will be built and maintained to other than the third connecting 
crosscut outby each working face (see Sec. 75.333(b)(1)).
    (p) The volume of air required at the intake to the longwall 
sections, if different than 30,000 cubic feet per minute (see 
Sec. 75.325(c)).
    (q) The velocities of air on a longwall or shortwall face, and the 
locations where the velocities must be measured (see 
Sec. 75.325(c)(2)).
    (r) The minimum quantity of air that will be provided during the 
installation and removal of mechanized mining equipment, the location 
where this quantity will be provided, and the ventilation controls that 
will be used. (see Sec. 75.325(d)).
    (s) The locations and frequency of the methane tests if required 
more often by Sec. 75.362(d)(1)(iii) (see Sec. 75.362 (d)(1)(iii).
    (t) The locations where samples for ``designated areas'' will be 
collected, including the specific location of each sampling device, and 
the respirable dust control measures used at the dust generating 
sources for these locations (see Sec. 70.208 of this chapter).
    (u) The methane and dust control systems at underground dumps, 
crushers, transfer points, and haulageways.
    (v) Areas in trolley haulage entries where the air velocity will be 
greater than 250 feet per minute and the velocity in these areas (see 
Sec. 75.327(b)).
    (w) Locations where entries will be advanced less than 20 feet from 
the inby rib without a crosscut being provided where a line brattice 
will be required. (see Sec. 75.333(g)).
    (x) A description of the bleeder system to be used, including its 
design (see Sec. 75.334).
    (y) The means for determining the effectiveness of bleeder systems 
(see Sec. 75.334(c)(2)).
    (z) The locations where measurements of methane and oxygen 
concentrations and air quantities and tests to determine whether the 
air is moving in the proper direction will be made to evaluate the 
ventilation of nonpillared worked-out areas (see Sec. 75.364 (a)(1)) 
and the effectiveness of bleeder systems (see Sec. 75.364 (a)(2)(iii). 
Alternative methods of evaluation of the effectiveness of bleeder 
systems (Sec. 75.364 (a)(2)(iv)).
    (aa) The means for adequately maintaining bleeder entries free of 
obstructions such as roof falls and standing water (see 
Sec. 75.334(c)(3)).
    (bb) The location of ventilation devices such as regulators, 
stoppings and bleeder connectors used to control air movement through 
worked-out areas (see Sec. 75.334(c)(4)). The location and sequence of 
construction of proposed seals for each worked-out area. (see 
Sec. 75.334(e)).
    (cc) In mines with a demonstrated history of spontaneous 
combustion: a description of the measures that will be used to detect 
methane, carbon monoxide, and oxygen concentration during and after 
pillar recovery and in worked-out areas where no pillars have been 
recovered (see Sec. 75.334(f)(1); and, the actions which will be taken 
to protect miners from the hazards associated with spontaneous 
combustion (see Sec. 75.334(f)(2). 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 (see Sec. 75.334(f)(3)).
    (dd) The location of all horizontal degasification holes that are 
longer than 1,000 feet and the location of all vertical degasification 
holes.
    (ee) If methane drainage systems are used, a detailed sketch of 
each system, including a description of safety precautions used with 
the systems.
    (ff) A description of the methods and materials to be used to seal 
worked-out areas if those methods or materials will be different from 
those specified by Sec. 75.335(a)(1).
    (gg) The alternative location for the additional sensing device if 
the device will not be installed on the longwall shearing machine (see 
Sec. 75.342(a)(2)).
    (hh) The ambient level in parts per million of carbon monoxide, and 
the method for determining the ambient level, in all areas where carbon 
monoxide sensors are installed.
    (ii) The distance that separation between the primary escapeway and 
the belt or track haulage entries will be maintained if other than to 
the first connecting crosscut outby the section loading point (see 
Sec. 75.380(g)).
    (jj) In anthracite mines, the dimensions of escapeways where the 
pitch of the coal seam does not permit escapeways to be maintained 4 
feet by 5 feet and the locations where these dimensions must be 
maintained (see Sec. 75.381(c)(4)).


Sec. 75.372 Mine ventilation map.

    (a)(1) At intervals not exceeding 12 months, the operator shall 
submit to the district manager 3 copies of an up-to-date map of the 
mine drawn to a scale of not less than 100 nor more than 500 feet to 
the inch. A registered engineer or a registered surveyor shall certify 
that the map is accurate.
    (2) In addition to the informational requirements of this section 
the map may also be used to depict and explain plan contents that are 
required in Sec. 75.371. Information shown on the map to satisfy the 
requirements of Sec. 75.371 shall be subject to approval by the 
district manager.
    (b) The map shall contain the following information:
    (1) The mine name, company name, mine identification number, a 
legend identifying the scale of the map and symbols used, and the name 
of the individual responsible for the information on the map.
    (2) All areas of the mine, including sealed and unsealed worked-out 
areas.
    (3) All known mine workings that are located in the same coalbed 
within 1,000 feet of existing or projected workings. These workings may 
be shown on a mine map with a scale other than that required by 
paragraph (a) of this section, if the scale does not exceed 2,000 feet 
to the inch and is specified on the map.
    (4) The locations of all known mine workings underlying and 
overlying the mine property and the distance between the mine workings.
    (5) The locations of all known oil and gas wells and all known 
drill holes that penetrate the coalbed being mined.
    (6) The locations of all main mine fans, installed backup fans and 
motors, and each fan's specifications, including size, type, model 
number, manufacturer, operating pressure, motor horsepower, and 
revolutions per minute.
    (7) The locations of all surface mine openings and the direction 
and quantity of air at each opening.
    (8) The elevation at the top and bottom of each shaft and slope, 
and shaft and slope dimensions, including depth and length.
    (9) The direction of air flow in all underground areas of the mine.
    (10) The locations of all active working sections and the four-
digit identification number for each mechanized mining unit (MMU).
    (11) The location of all escapeways.
    (12) The locations of all ventilation controls, including permanent 
stoppings, overcasts, undercasts, regulators, seals, airlock doors, 
haulageway doors and other doors, except temporary ventilation controls 
on working sections.
    (13) The direction and quantity of air--
    (i) Entering and leaving each split;
    (ii) In the last open crosscut of each set of entries and rooms; 
and 

[[Page 9843]]

    (iii) At the intake end of each pillar line, including any longwall 
or shortwall.
    (14) Projections for at least 12 months of anticipated mine 
development, proposed ventilation controls, proposed bleeder systems, 
and the anticipated location of intake and return air courses, belt 
entries, and escapeways.
    (15) The locations of existing methane drainage systems.
    (16) The locations of all atmospheric monitoring system sensors.
    (17) Contour lines that pass through whole number elevations of the 
coalbed being mined. These lines shall be spaced at 10-foot elevation 
levels unless a wider spacing is permitted by the district manager.
    (18) The location of proposed seals for each worked-out area.
    (19) The entry height, velocity and direction of the air current at 
or near the midpoint of each belt flight where the height and width of 
the entry are representative of the belt haulage entry.
    (20) The location and designation of air courses that have been 
redesignated from intake to return for the purpose of ventilation of 
structures, areas or installations that are required by this subpart D 
to be ventilated to return air courses, and for ventilation of seals.
    (c) The mine map required by Sec. 75.1200 may be used to satisfy 
the requirements for the ventilation map, provided that all the 
information required by this section is contained on the map.


Sec. 75.373 Reopening mines.

    After a mine is abandoned or declared inactive, and before it is 
reopened, mining operations shall not begin until MSHA has been 
notified and has completed an inspection.


Sec. 75.380 Escapeways; bituminous and lignite mines.

    (a) Except in situations addressed in Sec. 75.381, Sec. 75.385 and 
Sec. 75.386, at least two separate and distinct travelable passageways 
shall be designated as escapeways and shall meet the requirements of 
this section.
    (b) (1) Escapeways shall be provided from each working section, and 
each area where mechanized mining equipment is being installed or 
removed, continuous to the surface escape drift opening or continuous 
to the escape shaft or slope facilities to the surface.
    (2) During equipment installation, these escapeways shall begin at 
the projected location for the section loading point. During equipment 
removal, they shall begin at the location of the last loading point.
    (c) The two separate and distinct escapeways required by this 
section shall not end at a common shaft, slope, or drift opening, 
except that multiple compartment shafts or slopes separated by walls 
constructed of noncombustible material may be used as separate and 
distinct passageways.
    (d) Each escapeway shall be--
    (1) Maintained in a safe condition to always assure passage of 
anyone, including disabled persons;
    (2) Clearly marked to show the route and direction of travel to the 
surface;
    (3) Maintained to at least a height of 5 feet from the mine floor 
to the mine roof, excluding the thickness of any roof support, except 
that the escapeways shall be maintained to at least the height of the 
coalbed, excluding the thickness of any roof support, where the coalbed 
is less than 5 feet. In areas of mines where escapeways pass through 
doors, the height may be less than 5 feet, provided that sufficient 
height is maintained to enable miners, including disabled persons, to 
escape quickly in an emergency. In areas of mines developed before 
November 16, 1992, where escapeways pass over or under overcasts or 
undercasts, the height may be less than 5 feet provided that sufficient 
height is maintained to enable miners, including disabled persons, to 
escape quickly in an emergency. When there is a need to determine 
whether sufficient height is provided, MSHA may require a stretcher 
test where 4 persons carry a miner through the area in question on a 
stretcher;
    (4) Maintained at least 6 feet wide except--
    (i) Where necessary supplemental roof support is installed, the 
escapeway shall not be less than 4 feet wide; or
    (ii) Where the route of travel passes through doors or other 
permanent ventilation controls, the escapeway shall be at least 4 feet 
wide to enable miners to escape quickly in an emergency, or
    (iii) Where the alternate escapeway passes through doors or other 
permanent ventilation controls or where supplemental roof support is 
required and sufficient width is maintained to enable miners, including 
disabled persons, to escape quickly in an emergency. When there is a 
need to determine whether sufficient width is provided, MSHA may 
require a stretcher test where 4 persons carry a miner through the area 
in question on a stretcher, or
    (iv) Where mobile equipment near working sections, and other 
equipment essential to the ongoing operation of longwall sections, is 
necessary during normal mining operations, such as material cars 
containing rock dust or roof control supplies, or is to be used for the 
evacuation of miners off the section in the event of an emergency. In 
any instance, escapeways shall be of sufficient width to enable miners, 
including disabled persons, to escape quickly in an emergency. When 
there is a need to determine whether sufficient width is provided, MSHA 
may require a stretcher test where 4 persons carry a miner through the 
area in question on a stretcher;
    (5) Located to follow the most direct, safe and practical route to 
the nearest mine opening suitable for the safe evacuation of miners; 
and
    (6) Provided with ladders, stairways, ramps, or similar facilities 
where the escapeways cross over obstructions.
    (e) Surface openings shall be adequately protected to prevent 
surface fires, fumes, smoke, and flood water from entering the mine.
    (f) Primary escapeway. (1) One escapeway that is ventilated with 
intake air shall be designated as the primary escapeway.
    (2) Paragraphs (f)(3) through (f)(7) of this section apply as 
follows:
    (i) To all areas of a primary escapeway developed on or after 
November 16, 1992;
    (ii) Effective as of March 11, 1997, to all areas of a primary 
escapeway developed between March 30, 1970 and November 16, 1992; and
    (iii) Effective as of March 11, 1997, to all areas of the primary 
escapeway developed prior to March 30, 1970 where separation of the 
belt and trolley haulage entries from the primary escapeway existed 
prior to November 16, 1992.
    (3) The following equipment is not permitted in the primary 
escapeway:
    (i) Unattended operating diesel equipment without an automatic fire 
suppression system.
    (ii) Mobile equipment hauling coal except for hauling coal 
incidental to cleanup or maintenance of the primary escapeway.
    (iii) Compressors, except--
    (A) Compressors necessary to maintain the escapeway in safe, 
travelable condition;
    (B) Compressors that are components of equipment such as 
locomotives and rock dusting machines; and
    (C) Compressors of less than five horsepower.
    (iv) Underground transformer stations, battery charging stations, 
substations, and rectifiers except--
    (A) Where necessary to maintain the escapeway in safe, travelable 
condition; and
    (B) Battery charging stations and rectifiers and power centers with 


[[Page 9844]]
transformers that are either dry-type or contain nonflammable liquid, 
provided they are located on or near a working section and are moved as 
the section advances or retreats.
    (v) Water pumps, except--
    (A) Water pumps necessary to maintain the escapeway in safe, 
travelable condition;
    (B) Submersible pumps;
    (C) Permissible pumps and associated permissible switchgear;
    (D) Pumps located on or near a working section that are moved as 
the section advances or retreats;
    (E) Pumps installed in anthracite mines; and
    (F) Small portable pumps.
    (4) Mobile equipment operated in the primary escapeway, except for 
continuous miners and as provided in paragraphs (f)(5), (f)(6), and 
(f)(7) of this section, shall be equipped with a fire suppression 
system installed according to Secs. 75.1107-3 through 75.1107-16 that 
is--
    (i) Manually operated and attended continuously by a person trained 
in the systems function and use, or
    (ii) A multipurpose dry chemical type capable of both automatic and 
manual activation.
    (5) Personnel carriers and small mobile equipment designed and used 
only for carrying people and small hand tools may be operated in 
primary escapeways if--
    (i) The equipment is provided with a multipurpose dry chemical type 
fire suppression system capable of both automatic and manual 
activation, and the suppression system is suitable for the intended 
application and is listed or approved by a nationally recognized 
independent testing laboratory, or,
    (ii) Battery powered and provided with two 10 pound multipurpose 
dry chemical portable fire extinguishers.
    (6) Notwithstanding the requirements of paragraph (f)(3)(i), mobile 
equipment not provided with a fire suppression system may operate in 
the primary escapeway if no one is inby except those persons directly 
engaged in using or moving the equipment.
    (7) Notwithstanding the requirements of paragraph (f)(3)(i), mobile 
equipment designated and used only as emergency vehicles or ambulances, 
may be operated in the primary escapeway without fire suppression 
systems.
    (g) Except where separation of belt and trolley haulage entries 
from designated escapeways did not exist before November 15, 1992, the 
primary escapeway shall be separated from belt and trolley haulage 
entries for its entire length, to and including the first connecting 
crosscut outby each loading point except when a greater or lesser 
distance for this separation is specified and approved in the 
ventilation plan and does not pose a hazard to miners.
    (h) Alternate escapeway. One escapeway shall be designated as the 
alternate escapeway. The alternate escapeway shall be separated from 
the primary escapeway for its entire length, except that the alternate 
and primary escapeways may be ventilated from a common intake air shaft 
or slope opening.
    (i) Mechanical escape facilities shall be provided and maintained 
for--
    (1) Each shaft that is part of a designated escapeway and is 
greater than 50 feet in depth; and
    (2) Each slope from the coal seam to the surface that is part of a 
designated escapeway and is inclined more than 9 degrees from the 
horizontal.
    (j) Within 30 minutes after mine personnel on the surface have been 
notified of an emergency requiring evacuation, mechanical escape 
facilities provided under paragraph (i) of this section shall be 
operational at the bottom of shaft and slope openings that are part of 
escapeways.
    (k) Except where automatically activated hoisting equipment is 
used, the bottom of each shaft or slope opening that is part of a 
designated escapeway shall be equipped with a means of signaling a 
surface location where a person is always on duty when anyone is 
underground. When the signal is activated or the evacuation of persons 
underground is necessary, the person shall assure that mechanical 
escape facilities are operational as required by paragraph (j) of this 
section.
    (l) (1) Stairways or mechanical escape facilities shall be 
installed in shafts that are part of the designated escapeways and that 
are 50 feet or less in depth, except ladders may be used in shafts that 
are part of the designated escapeways and that are 5 feet or less in 
depth.
    (2) Stairways shall be constructed of concrete or metal, set on an 
angle not to exceed 45 degrees from the horizontal, and equipped on the 
open side with handrails. In addition, landing platforms that are at 
least 2 feet by 4 feet shall be installed at intervals not to exceed 20 
vertical feet on the stairways and equipped on the open side with 
handrails.
    (3) Ladders shall be constructed of metal, anchored securely, and 
set on an angle not to exceed 60 degrees from the horizontal.
    (m) A travelway designed to prevent slippage shall be provided in 
slope and drift openings that are part of designated escapeways, unless 
mechanical escape facilities are installed.


Sec. 75.381 Escapeways; anthracite mines.

    (a) Except as provided in Secs. 75.385 and 75.386, at least two 
separate and distinct travelable passageways shall be designated as 
escapeways and shall meet the requirements of this section.
    (b) Escapeways shall be provided from each working section 
continuous to the surface.
    (c) Each escapeway shall be--
    (1) Maintained in a safe condition to always assure passage of 
anyone, including disabled persons;
    (2) Clearly marked to show the route of travel to the surface;
    (3) Provided with ladders, stairways, ramps, or similar facilities 
where the escapeways cross over obstructions; and
    (4) Maintained at least 4 feet wide by 5 feet high. If the pitch or 
thickness of the coal seam does not permit these dimensions to be 
maintained other dimensions may be approved in the ventilation plan.
    (d) Surface openings shall be adequately protected to prevent 
surface fires, fumes, smoke, and flood water from entering the mine.
    (e) Primary escapeway. One escapeway that shall be ventilated with 
intake air shall be designated as the primary escapeway.
    (f) Alternate escapeway. One escapeway that shall be designated as 
the alternate escapeway shall be separated from the primary escapeway 
for its entire length.
    (g) Mechanical escape facilities shall be provided--
    (1) For each shaft or slope opening that is part of a primary 
escapeway; and
    (2) For slopes that are part of escapeways, unless ladders are 
installed.
    (h) Within 30 minutes after mine personnel on the surface have been 
notified of an emergency requiring evacuation, mechanical escape 
facilities shall be operational at the bottom of each shaft and slope 
opening that is part of an escapeway.
    (i) Except where automatically activated hoisting equipment is 
used, the bottom of each shaft or slope opening that is part of a 
primary escapeway shall be equipped with a means of signaling a surface 
location where a person is always on duty when anyone is underground. 
When the signal is activated or the evacuation of personnel is 
necessary, the person on duty shall assure that mechanical escape 
facilities are operational as required by paragraph (h) of this 
section. 

[[Page 9845]]



Sec. 75.382 Mechanical escape facilities.

    (a) Mechanical escape facilities shall be provided with overspeed, 
overwind, and automatic stop controls.
    (b) Every mechanical escape facility with a platform, cage, or 
other device shall be equipped with brakes that can stop the fully 
loaded platform, cage, or other device.
    (c) Mechanical escape facilities, including automatic elevators, 
shall be examined weekly. The weekly examination of this equipment may 
be conducted at the same time as a daily examination required by 
Sec. 75.1400-3.
    (1) The weekly examination shall include an examination of the 
headgear, connections, links and chains, overspeed and overwind 
controls, automatic stop controls, and other facilities.
    (2) At least once each week, the hoist shall be run through one 
complete cycle of operation to determine that it is operating properly.
    (d) A person trained to operate the mechanical escape facility 
always shall be available while anyone is underground to provide the 
mechanical escape facilities, if required, to the bottom of each shaft 
and slope opening that is part of an escapeway within 30 minutes after 
personnel on the surface have been notified of an emergency requiring 
evacuation. However, no operator is required for automatically operated 
cages, platforms, or elevators.
    (e) Mechanical escape facilities shall have rated capacities 
consistent with the loads handled.
    (f) Manually-operated mechanical escape facilities shall be 
equipped with indicators that accurately and reliably show the position 
of the facility.
    (g) Certification. The person making the examination as required by 
paragraph (c) of this section shall certify by initials, date, and the 
time that the examination was made. Certifications shall be made at or 
near the facility examined.


Sec. 75.383 Escapeway maps and drills.

    (a) A map shall be posted or readily accessible to all miners in 
each working section, and in each area where mechanized mining 
equipment is being installed or removed. The map shall show the 
designated escapeways from the working section to the location where 
miners must travel to satisfy the escapeway drill specified in 
paragraph (b)(1) of this section. A map showing the main escapeways 
shall be posted at a surface location of the mine where miners 
congregate, such as at the mine bulletin board, bathhouse, or waiting 
room. All maps shall be kept up to date, and any changes in route of 
travel, locations of doors, or directions of airflow shall be shown on 
the maps by the end of the shift on which the changes are made, and 
affected miners shall be informed of the changes before entering the 
underground areas of the mine. Miners underground on a shift when any 
such change is made shall be immediately notified of the change.
    (b) (1) At least once every 90 days, each miner, including miners 
with working stations located between working sections and main 
escapeways, shall participate in a practice escapeway drill. During 
this drill, each miner shall travel the primary or alternate escapeway 
from the miner's working section or area where mechanized mining 
equipment is being installed or removed, to the area where the split of 
air ventilating the working section intersects a main air course, or 
2,000 feet outby the section loading point, whichever distance is 
greater. Other miners shall participate in the escapeway drill by 
traveling in the primary or alternate escapeway for a distance of 2,000 
feet from their working station toward the nearest escape facility or 
drift opening. An escapeway drill shall not be conducted in the same 
escapeway as the immediately preceding drill.
    (2) At least once every 6 weeks and for each shift, at least two 
miners on each coal producing working section who work on that section, 
accompanied by the section supervisor, shall participate in a practice 
escape drill and shall travel the primary or alternate escapeway from 
the location specified in paragraph (b)(1) of this section, to the 
surface, to mechanical escape facilities, or to an underground entrance 
to a shaft or slope to the surface. Systematic rotation of section 
personnel shall be used so that all miners participate in this drill. 
An escapeway drill shall not be conducted in the same escapeway as the 
immediately preceding drill.
    (3) At least once every 6 weeks, at least two miners on each 
maintenance shift and a supervisor, shall participate in a practice 
escape drill and shall travel the primary or alternate escapeway from 
the location specified in paragraph (b)(1) of this section, to the 
surface, to mechanical escape facilities, or to an underground entrance 
to a shaft or slope to the surface. Systematic rotation of maintenance 
personnel and working sections shall be used so that all miners 
participate in this drill and the escapeways from all sections are 
traveled. An escapeway drill shall not be conducted in the same 
escapeway as the immediately preceding drill.
    (4) Before or during practice escapeway drills, miners shall be 
informed of the locations of fire doors, check curtains, changes in the 
routes of travel, and plans for diverting smoke from escapeways.
    (c) The practice escapeway drills may be used to satisfy the 
evacuation specifications of the fire drills required by Sec. 75.1101-
23.


Sec. 75.384 Longwall and shortwall travelways.

    (a) If longwall or shortwall mining systems are used and the two 
designated escapeways required by Sec. 75.380 are located on the 
headgate side of the longwall or shortwall, a travelway shall be 
provided on the tailgate side of that longwall or shortwall. The 
travelway shall be located to follow the most direct and safe practical 
route to a designated escapeway.
    (b) The route of travel shall be clearly marked.
    (c) When a roof fall or other blockage occurs that prevents travel 
in the travelway--
    (1) Work shall cease on the longwall or shortwall face;
    (2) Miners shall be withdrawn from face areas to a safe area outby 
the section loading point; and
    (3) MSHA shall be notified.
    (d) Work may resume on the longwall or shortwall face after the 
procedures set out in Secs. 75.215 and 75.222 are implemented.


Sec. 75.385 Opening new mines.

    When new mines are opened, no more than 20 miners at a time shall 
be allowed in any mine until a connection has been made between the 
mine openings, and these connections shall be made as soon as possible.


Sec. 75.386 Final mining of pillars.

    When only one mine opening is available due to final mining of 
pillars, no more than 20 miners at a time shall be allowed in the mine, 
and the distance between the mine opening and working face shall not 
exceed 500 feet.


Sec. 75.388 Boreholes in advance of mining.

    (a) Boreholes shall be drilled in each advancing working place when 
the working place approaches--
    (1) To within 50 feet of any area located in the mine as shown by 
surveys that are certified by a registered engineer or registered 
surveyor unless the area has been preshift examined;
    (2) To within 200 feet of any area located in the mine not shown by 
surveys that are certified by a registered engineer or registered 
surveyor unless the area has been preshift examined; or
    (3) To within 200 feet of any mine workings of an adjacent mine 
located in 

[[Page 9846]]
the same coalbed unless the mine workings have been preshift examined.
    (b) Boreholes shall be drilled as follows:
    (1) Into the working face, parallel to the rib, and within 3 feet 
of each rib.
    (2) Into the working face, parallel to the rib, and at intervals 
across the face not to exceed 8 feet.
    (3) At least 20 feet in depth in advance of the working face, and 
always maintained to a distance of 10 feet in advance of the working 
face.
    (c) Boreholes shall be drilled in both ribs of advancing working 
places described in paragraph (a) of this section unless an alternative 
drilling plan is approved by the District Manager in accordance with 
paragraph (g) of this section. These boreholes shall be drilled--
    (1) At an angle of 45 degrees to the direction of advance;
    (2) At least 20 feet in depth; and
    (3) At intervals not to exceed 8 feet.
    (d) When a borehole penetrates an area that cannot be examined, and 
before mining continues, a certified person shall, if possible, 
determine--
    (1) The direction of airflow in the borehole;
    (2) The pressure differential between the penetrated area and the 
mine workings;
    (3) The concentrations of methane, oxygen, carbon monoxide, and 
carbon dioxide; and
    (4) Whether water is impounded within the penetrated area.
    (e) Unless action is taken to dewater or to ventilate penetrated 
areas, boreholes shall be plugged with wooden plugs or similar devices 
when--
    (1) Tests conducted at the boreholes show that the atmosphere in 
the penetrated area contains more than 1.0 percent methane, less than 
19.5 percent oxygen, or harmful concentrations of carbon monoxide, 
carbon dioxide or other explosive, harmful or noxious gases;
    (2) Tests for methane, oxygen, carbon monoxide, and carbon dioxide 
cannot be made because air from mine workings is flowing into the 
penetrated area; or
    (3) Water is discharging through the boreholes from the penetrated 
area into the mine workings.
    (f) If mining is to be conducted within 50 feet above or below an 
inaccessible area of another mine, boreholes shall be drilled, as 
necessary, according to a plan approved by the district manager.
    (g) Alternative borehole patterns that provide the same protection 
to miners as the pattern established by paragraphs (b) and (c) of this 
section may be used under a plan approved by the district manager.


Sec. 75.389 Mining into inaccessible areas.

    (a) (1) The operator shall develop and follow a plan for mining 
into areas penetrated by boreholes drilled under Sec. 75.388.
    (2) Mining shall not resume into any area penetrated by boreholes 
until conditions in the penetrated area can be determined under 
Sec. 75.388 and the plan for mining-through into the area has been 
approved by the district manager.
    (3) A copy of the procedures to be followed shall be posted near 
the site of the mining-through operations and the operator shall 
explain these procedures to all miners involved in the operations.
    (b) The procedures specified in the plan shall include--
    (1) The method of ventilation, ventilation controls, and the air 
quantities and velocities in the affected working section and working 
place;
    (2) Dewatering procedures to be used if a penetrated area contains 
a water accumulation; and
    (3) The procedures and precautions to be followed during mining-
through operations.
    (c) Except for routine mining-through operations that are part of a 
retreat section ventilation system approved in accordance with 
Sec. 75.371(f) and (x), the following provisions shall apply:
    (1) Before and during mining-through operations, a certified person 
shall perform air quality tests at intervals and at locations necessary 
to protect the safety of the miners.
    (2) During mining-through operations, only persons involved in 
these operations shall be permitted in the mine; and
    (3) After mining-through, a certified person shall determine that 
the affected areas are safe before any persons enter the underground 
areas of the mine.

[FR Doc. 96-5453 Filed 3-6-96; 11:23 am]
BILLING CODE 4510-43-P