Section 57.22309 - Methane monitors (V-A mines)(a) Methane monitors shall be installed on continuous mining machines used in or beyond the last open crosscut.(b) The monitors shall-(1) Give warning at 1.0 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 of such equipment when methane levels reach 1.5 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.