MSHA - Code of Federal Regulations - 30 CFR 75.1725
30 CFR § 75.1725
Machinery and equipment; operation and maintenance.
(a) Mobile and stationary machinery and equipment shall be maintained
in safe operating condition and machinery or equipment in unsafe condition
shall be removed from service immediately.
(b) Machinery and equipment shall be operated only by persons
authorized to operate such machinery or equipment.
(c) Repairs or maintenance shall not be performed on machinery until
the power is off and the machinery is blocked against motion, except where
machinery motion is necessary to make adjustments.
(d) Machinery shall not be lubricated manually while in motion,
unless equipped with extended fittings or cups.
[38 FR 4976, Feb. 23, 1973]