30 CFR 57.4131 - Surface fan installations and mine openings.
(a) On the surface, no more than one day's supply of combustible materials shall be stored within 100 feet of mine openings or within 100 feet of fan installations used for underground ventilation.
(b) the one-day supply shall be kept at least 25 feet away from any mine opening except during transit into the mine.
Title 30 published on 2013-07-01
no entries appear in the Federal Register after this date.