30 CFR Part 57Public Domain
§ 57.22220 — Air passing unsealed areas (I-A, II-A, III, and V-A mines)
Subpart T — Safety Standards for Methane in Metal and Nonmetal Mines
Air that has passed by or through unsealed abandoned or unsealed inactive areas and contains 0.25 percent or more methane shall—
(a)Be coursed directly to a return airway;
(b)Be tested daily for methane by a competent person; and
(c)Not be used to ventilate work places.
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.