Description of typical mine-telephone systems and suggestions for making improved installations

Author:	Brown, C. L.
Year:	1946
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7385
Series:	Information circular / United States Department of the Interior, Bureau of Mines ;
Report Number:	7385
Subjects:	Mine safety
	Telephone
Link:	https://hdl.handle.net/2027/mdp.39015074127740