StacksVerified U.S. regulatory reference

30 CFR §75.1711-2

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
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.