State regulations governing the use of trolley wires in mines

Author:	Ilsley, L. C.
Additional Authors:	Kearns, R. A.
Year:	1929
Document Type:	MAIN
Issuing Agency:	U.S. Dept. of Commerce, Bureau of Mines,
SUDOC:	C 22.11:6220
Series:	Information circular / Bureau of Mines ;
Report Number:	6220
Subjects:	Coal mines and mining--Safety measures
	Electricity in mining
Link:	https://hdl.handle.net/2027/mdp.39015095082478