30 CFR § 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. This minimum also applies to
sections which are not operating but are capable of producing coal by simply
energizing the equipment on the section.
(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 in accordance with 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.
(f) The minimum ventilating air quantity for an individual unit of
diesel-powered equipment being operated shall be at least that
specified on the approval plate for that equipment. Such air quantity
shall be maintained--
(1) In any working place where the equipment is being operated;
(2) At the section loading point during any shift the equipment is
being operated on the working section;
(3) In any entry where the equipment is being operated outby the
section loading point in areas of the mine developed on or after April
25, 1997;
(4) In any air course with single or multiple entries where the
equipment is being operated outby the section loading point in areas of
the mine developed prior to April 25, 1997; and
(5) At any other location required by the district manager and
specified in the approved ventilation plan.
(g) The minimum ventilating air quantity where multiple units of
diesel-powered equipment are operated on working sections and in areas
where mechanized mining equipment is being installed or removed must be
at least the sum of that specified on the approval plates of all the
diesel-powered equipment on the working section or in the area where
mechanized mining equipment is being installed or removed. The minimum
ventilating air quantity shall be specified in the approved ventilation
plan. For working sections such air quantity must be maintained--
(1) In the last open crosscut of each set of entries or rooms in
each working section;
(2) In the intake, reaching the working face of each longwall; and
(3) At the intake end of any pillar line.
(h) The following equipment may be excluded from the calculations
of ventilating air quantity under paragraph (g) if such equipment
exclusion is approved by the district manager and specified in the
ventilation plan:
(1) Self-propelled equipment meeting the requirements of
§ 75.1908(b);
(2) Equipment that discharges its exhaust into intake air that is
coursed directly to a return air course;
(3) Equipment that discharges its exhaust directly into a return
air course; and
(4) Other equipment having duty cycles such that the emissions
would not significantly affect the exposure of miners.
(i) A ventilating air quantity that is less than what is required
by paragraph (g) of this section may be approved by the district
manager in the ventilation plan based upon the results of sampling that
demonstrate that the lesser air quantity will maintain continuous
compliance with applicable TLV®'s.
(j) If during sampling required by § 70.1900(c) of this
subchapter the ventilating air is found to contain concentrations of CO
or NO2 in excess of the action level specified by § 70.1900(c),
higher action levels may be approved by the district manager based on
the results of sampling that demonstrate that a higher action level
will maintain continuous compliance with applicable TLV®'s.
Action levels other than those specified in § 70.1900(c) shall be
specified in the approved ventilation plan.
(k) As of November 25, 1997 the ventilating air quantity required
where diesel-powered equipment is operated shall meet the requirements
of paragraphs (f) through (j) of this section. Mine operators utilizing
diesel-powered equipment in underground coal mines shall submit to the
appropriate MSHA district manager a revised ventilation plan or
appropriate amendments to the existing plan, in accordance with
§ 75.371, which implement the requirements of paragraphs (f) through
(j) of this section.
[61 FR 9828, Mar. 11, 1996; 61 FR 26442, May 28, 1996; 61 FR 29288, June 10, 1996, as amended at 61 FR 55526, Oct. 25, 1996; 62 FR 34611, June 27, 1997]