Mine power systems research(in four parts) :

Year:	1979
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines :
Series:	Information circular - Bureau of Mines ;
Report Number:	8800.
Subjects:	Electric currents--Grounding
	Mining machinery
	Electricity in mining
Link:	https://hdl.handle.net/2027/mdp.39015078464057