StacksVerified U.S. regulatory reference

30 CFR §33.31

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)Drilling tests shall be conducted in a test space formed by two curtains suspended across a mine opening in such a manner that the volume of the test space shall be approximately 2,000 cubic feet.
  2. (b)No mechanical ventilation shall be provided in the test space during a drilling test, except such air movement as may be induced by operation of drilling- or dust-collecting equipment.
  3. (c)All parts of a unit or system shall be within the test space during a drilling test.