30 CFR § 7.81
Purpose and effective date.
Subpart A general provisions of this part apply to this subpart E.
Subpart E establishes the specific engine performance and exhaust
emission requirements for MSHA approval of diesel engines for use in
areas of underground coal mines where permissible electric equipment is
required and areas where non-permissible electric equipment is allowed.
It is effective November 25, 1996.