30 C.F.R. § 57.22217 Seals and stoppings (I-A, I-B, and I-C mines).
Title 30 - Mineral Resources
All seals, and those stoppings that separate main intake from main return airways, shall be of substantial construction and constructed of noncombustible materials, except that stoppings constructed of brattice materials may be used in face areas.
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
§ 57.22217 Seals and stoppings (I-A, I-B, and I-C mines).
