Section 57.22307 - Methane monitors (II-A mines)(a) Methane monitors shall be installed on continuous mining machines, longwall mining systems, bench and face drills, and undercutting machines used in or beyond the last open crosscut.(b) The monitors shall-(1) Give warning at 0.5 percent methane;(2) Automatically deenergize electrical equipment, except power to monitoring equipment determined by MSHA to be intrinsically safe under 30 CFR part 18 , and prevent starting such equipment when methane levels reach 1.0 percent; and(3) Automatically deenergize the equipment when power to a sensor is interrupted.(c) Sensing units of monitors shall be positioned at a location which provides for the most effective measurement of methane.