Section 75.1908 - Nonpermissible diesel-powered equipment; categories(a) Heavy-duty diesel-powered equipment includes- (1) Equipment that cuts or moves rock or coal;(2) Equipment that performs drilling or bolting functions;(3) Equipment that moves longwall components;(4) Self-propelled diesel fuel transportation units and self-propelled lube units; or(5) Machines used to transport portable diesel fuel transportation units or portable lube units.(b) Light-duty diesel-powered equipment is any diesel-powered equipment that does not meet the criteria of paragraph (a).(c) For the purposes of this subpart, the following equipment is considered attended: (1) Any machine or device operated by a miner; or(2) Any machine or device that is mounted in the direct line of sight of a job site located within 500 feet of such machine or device, which job site is occupied by a miner.(d) Diesel-powered ambulances and fire fighting equipment are a special category of equipment that may be used underground only in accordance with the mine fire fighting and evacuation plan under § 75.1502 .61 FR 55527, Oct. 25, 1996; 70 FR 36347 , June 23, 2005