30 CFR § 75.342
(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
(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 electric equipment or shut down
diesel-powered equipment on which the monitor is
(c) The methane monitor shall automatically deenergize electric
equipment or shut down diesel-powered equipment on which it is mounted
(1) The methane concentration at any methane monitor reaches 2.0
(2) The monitor is not operating properly.
[61 FR 9829, Mar.11, 1996, as amended at 61 FR 55527, Oct. 25, 1996]