A. Tests for methane concentration under this section shall be made by certified or qualified persons trained in the use of an approved detecting device that is properly maintained and calibrated. Tests shall be made at least one foot from the roof, face, ribs, and floor.
B. If a methane concentration of one percent or more is present in a working place; an intake air course, including an air course in which a belt conveyor is located; or an area where mining equipment is being installed or removed, work shall cease and electrically powered equipment shall be de-energized in the affected working place, except for any intrinsically safe atmospheric monitoring system (AMS), which need not be de-energized. Changes or adjustments shall be made to such ventilation system to reduce the methane concentration to below one percent. Only work to reduce the methane concentration to below one percent is permitted. Such limitation does not apply to any other face in the entry or slope in which work can be safely continued.
C. If a methane concentration of 1.5 percent or more is present in a working place; an intake air course, including an air course in which a belt conveyor is located; or an area where mining equipment is being installed or removed, only work necessary to reduce the methane concentration to less than 1.5 percent is permitted, and all miners except those required to perform such necessary work shall be withdrawn from the affected area. Electrically powered equipment in the affected area shall be de-energized and other mechanized equipment in the affected area shall be shut off, except for any intrinsically safe AMS.
D. If a methane concentration of one percent or more is present in a return or split between the last working place on a working section and the location at which such split of air meets another split of air, or the location at which such split is used to ventilate a seal or worked-out area, changes or adjustments shall be made to the ventilation system to reduce the methane concentration in the return air to less than one percent.
E. If a methane concentration of 1.5 percent or more is present in a return air split between the last working place on a working section and the location at which such split of air meets another split of air, or the location at which such split is used to ventilate a seal or worked-out area, all miners except those required to perform necessary work to correct the problem shall be withdrawn from the affected area. Other than an intrinsically safe AMS, all equipment in the affected area shall be de-energized at the source. No other work is permitted in the affected area until the methane concentration in the return air is less than one percent.
F. An alternative methane concentration of as much as 1.5 percent is allowed in a return air split if the following conditions are met: (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; (ii) the methane concentration in the split is continuously monitored during mining operations by an intrinsically safe AMS that gives a visual and audible signal on the working section when the methane concentration in the return air reaches 1.5 percent; 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 that is immediately outby the most inby monitoring point or inby such point if the mechanical duster is maintained in a permissible condition and does not adversely affect the AMS. If a methane concentration of 1.5 percent or more is present at the location at which a return air alternative is applied, all persons shall be withdrawn, except those necessary to improve ventilation, and changes or adjustments shall be made to reduce the methane concentration in the return air to below 1.5 percent as set forth in subsection E.
G. The methane concentration in a bleeder split of air immediately before the air in such split joins another split of air, or in a return air course other than described in subsections D and E, shall not exceed two percent.
Code 1950, § 45-60.3; 1954, c. 191; 1966, c. 594, § 45.1-58; 1978, c. 120; 1994, c. 28, § 45.1-161.222; 1996, c. 774; 1999, c. 256; 2021, Sp. Sess. I, c. 387.