30 C.F.R. § 57.22241 Advance face boreholes (I-C mines).
Title 30 - Mineral Resources
(a) Boreholes shall be drilled at least 25 feet in advance of a face whenever the work place is within— (1) 50 feet of a surveyed abandoned mine or abandoned workings which cannot be inspected; or (2) 200 feet of an unsurveyed abandoned mine or abandoned workings which cannot be inspected. (b) Boreholes shall be drilled in such a manner to insure that the advancing face will not accidently break into an abandoned mine or abandoned working.
Title 30: Mineral Resources
PART 57—SAFETY AND HEALTH STANDARDS—UNDERGROUND METAL AND NONMETAL MINES
Subpart T—Safety Standards for Methane in Metal and Nonmetal Mines
Ventilation
§ 57.22241 Advance face boreholes (I-C mines).
