(c) Acetylene taken underground shall be in cylinders and shall be limited to necessary quantities. It shall be stored in a well-ventilated, fire-resistant location.

Empty cylinders shall be removed from the mine without unnecessary delay.

(d) (4-65) The following precautions shall be taken when welding equipment, blow torches, or other heat-producing devices or materials are used in a mine:

1. (1) All flammable materials within a radius of 10 feet shall be made wet with water before hot work is begun and again after hot work is finished.
2. (2) Any flammable materials at a greater distance than 10 feet upon which sparks or hot metal can fall shall be made wet with water before hot work is begun and again after hot work is finished.
3. (3) Before hot work is commenced in a shaft, a noncombustible barrier shall be installed to prevent sparks from falling below.
4. (4) A fire extinguisher or water hose ready for use shall be at the operation until the hot work is finished.
5. (5) The area where hot work was done shall be inspected for smoldering fires between one and two hours after hot work is finished.