Ala. Code § 25-9-83: Standards as to Volume of Air.

Sufficient air must be circulated and conducted through all entries, slopes, travelways, working places, air courses, and open abandoned areas to dilute, render harmless, and carry off noxious and explosive gases emitted in the mine, including smoke from blasting, and shall be not less than 150 cubic feet per man per minute. If mules or horses are used in a mine, 500 cubic feet per animal per minute must be provided in addition to the minimum volume specified for men.