C. Underground transformer stations, battery-charging stations, substations, rectifiers, and water pumps shall be housed in noncombustible structures or areas, or be equipped with an approved fire suppression system. These installations shall be ventilated with intake air that is coursed into a return air course or to the surface, and that is not used to ventilate working places. This requirement does not apply to: (i) rectifiers, power centers with transformers that are either dry-type or contain nonflammable liquid, or battery-charging stations, if they are located at or near the working section and are moved as the working section advances or retreats, (ii) submersible pumps, (iii) permissible pumps and associated permissible switch gear, (iv) pumps located at or near the working section that are moved as the working section advances or retreats, and (v) small portable pumps. Such equipment shall be installed and operated only in well-ventilated locations.
D. Changes in ventilation that materially affect the main air current or any split thereof shall be made when the mine is not in operation and there are no miners in the mine other than those engaged in changing the ventilation.
Code 1950, §§ 45-60.4, 45-71; 1954, c. 191; 1966, c. 594, § 45.1-57; 1978, c. 120; 1994, c. 28; 1996, c. 774; 1999, c. 256.