30 CFR Part 57Public Domain
§ 57.4533 — Mine opening vicinity
Subpart C — Fire Prevention and Control
Surface buildings or other similar structures within 100 feet of mine openings used for intake air or within 100 feet of mine openings that are designated escapeways in exhaust air shall be—
(a)Constructed of noncombustible materials; or
(b)Constructed to meet a fire resistance rating of no less than one hour; or
(c)Provided with an automatic fire suppression system; or
(d)Covered on all combustible interior and exterior structural surfaces with noncombustible material or limited combustible material, such as five-eighth inch, type “X” gypsum wallboard.
Public Domain: 30 CFR Part 57 (MSHA Safety and Health Standards — Underground Metal and Nonmetal Mines) is a U.S. government publication and is not subject to copyright. Text extracted from the official source ↗. Figures are served from the eCFR; if one does not load, use the link in its place.