§ 57.22220. Air passing unsealed areas (I-A, II-A, III, and V-A mines).
48 words·~1 min read·
/us/cfr/t30/s§ 57.22220·A research copy — for the controlling text, always check the official state or federal source. Not legal advice.
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.