30 C.F.R. § 33.31 Test space.
Title 30 - Mineral Resources
(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. (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. (c) All parts of a unit or system shall be within the test space during a drilling test.
Title 30: Mineral Resources
PART 33—DUST COLLECTORS FOR USE IN CONNECTION WITH ROCK DRILLING IN COAL MINES
Subpart C—Test Requirements
§ 33.31 Test space.
