(a) The ventilation of mines, the systems for which extend for more than two hundred feet underground and which are opened after the effective date of this article, shall be produced by a mechanically operated fan or mechanically operated fans. Ventilation by means of a furnace is prohibited in any mine. The fan or fans shall be kept in continuous operation, unless written permission to do otherwise be granted by the director. In case of interruption to a ventilating fan or its machinery whereby the ventilation of the mine is interrupted, immediate action shall be taken by the mine operator or the operator's management personnel, in all mines, to cut off the power and withdraw the men from the face regions or other areas of the mine affected. If ventilation is restored in fifteen minutes, the face regions and other places in the affected areas where gas (methane) is likely to accumulate, shall be reexamined by a certified person; and if found free of explosive gas, power may be restored and work resumed. If ventilation is not restored in fifteen minutes, all underground employees shall be removed from the mine, all power shall be cut off in a timely manner, and the underground employees shall not return until ventilation is restored and the mine examined by certified persons, mine examiners or other persons holding a certificate to make preshift examination. If ventilation is restored to the mine before miners reach the surface, the miners may return to underground working areas only after an examination of the areas is made by a certified person and the areas are determined to be safe.
(b) All main fans installed after the effective date of this article shall be located on the surface in fireproof housings offset not less than fifteen feet from the nearest side of the mine opening, equipped with fireproof air ducts, provided with explosion doors or a weak wall, and operated from an independent power circuit. In lieu of the requirements for the location of fans and pressure-relief facilities, a fan may be directly in front of, or over a mine opening: Provided, That such opening is not in direct line with possible forces coming out of the mine if an explosion occurs: Provided, however, That there is another opening having a weak wall stopping or explosion doors that would be in direct line with forces coming out of the mine. All main fans shall be provided with pressure-recording gauges or water gauges. A daily inspection shall be made of all main fans and machinery connected therewith by a certified electrician and a record kept of the same in a book prescribed for this purpose or by adequate facilities provided to permanently record the performance of the main fans and to give warning of an interruption to a fan.
(c) Auxiliary fans and tubing shall be permitted to be used in lieu of or in conjunction with line brattice to provide adequate ventilation to the working faces: Provided, That auxiliary fans be so located and operated to avoid recirculation of air at any time. Auxiliary fans shall be approved and maintained as permissible.
(d) If the auxiliary fan is stopped or fails, the electrical equipment in the place shall be stopped and the power disconnected at the power source until ventilation in the working place is restored. During such stoppage, the ventilation shall be by means of the primary air current conducted into the place in a manner to prevent accumulation of methane.
(e) In places where auxiliary fans and tubing are used, the ventilation between shifts, weekends and idle shifts shall be provided to face areas with line brattice or the equivalent to prevent accumulation of methane.
(f) The director may require that when continuous mine equipment is being used, all face ventilating systems using auxiliary fans and tubing shall be provided with machine-mounted diffuser fans, and such fans shall be continuously operated during mining operations.
(g) In the event of a fire or explosion in any coal mine, the ventilating fan or fans shall not intentionally be started, stopped, speed increased or decreased or the direction of the air current changed without the approval of the general mine foreman, and, if he or she is not immediately available, a representative of the Office of Miners' Health, Safety and Training. A duly authorized representative of the employees should be consulted if practical under the circumstances.