30 CFR § 75.1106
Welding, cutting, or soldering with arc or flame underground.
All welding, cutting, or soldering with arc or flame in all underground areas
of a coal mine shall, whenever practicable, be conducted in fireproof
enclosures. Welding, cutting, or soldering with arc or flame in other than a
fireproof enclosure shall be done under the supervision of a qualified person
who shall make a diligent search for fire during and after such operations
and shall, immediately before and during such operations, continuously test
for methane with means approved by the Secretary for detecting methane.
Welding, cutting, or soldering shall not be conducted in air that contains
1.0 volume per centum or more of methane. Rock dust or suitable fire
extinguishers shall be immediately available during such welding, cutting or