NAC512.154. Underground mines: Requirements for fresh air and ventilation.

     1. The operator of every underground mine shall provide and maintain a ventilation of at least 200 cubic feet per minute of fresh air for each person working in the mine.

     2. Every operator shall do everything reasonably in his or her power to furnish and encourage the use of any appliances for allaying dust.

     3. The air currents going into underground working, must, under all conditions, have sufficient volume and velocity to direct and carry away smoke and harmful gases from blasting, and any other gases or dusts which might contaminate the atmosphere to a degree in excess of the accepted minimum.

     4. In any underground workings where the Chief considers it necessary for the welfare of the employees, mechanically produced and positively controlled air currents must be provided.

     5. Internal combustion engines must not be used underground unless an application for the use has been filed with the Chief and is approved.

     6. If an application to use an internal combustion engine underground is approved by the Chief, the designated equipment may be used only so long as it is operated and maintained in accordance with recommendations made public from time to time by the United States Bureau of Mines and only upon the condition that whenever safe conditions of air quality are not maintained, the operator stops operation of the equipment until proper conditions of air quality are again established, either by increasing ventilation or by correcting mechanical imperfections in the equipment, whichever is found to be the cause of the undesirable conditions.

     [Inspector of Mines, Part 1 No. 5 subsecs. a-f, eff. 8-13-75]—(NAC A by Div. of Mine Inspection, 8-26-83)