30 C.F.R. § 75.1711-2
Current through May 31, 2024
Slope or drift openings required to be sealed under § 75.1711 shall be sealed with solid, substantial, incombustible material, such as concrete blocks, bricks or tile, or shall be completely filled with incombustible material for a distance of at least 25 feet into such openings.
30 C.F.R. §75.1711-2