Some signaling systems in metal-mine shafts

Author:	Mosier, McHenry
Additional Authors:	Gleim, E. J.
Year:	1939
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7083
Series:	Information circular / Bureau of Mines ;
Report Number:	7083
Subjects:	Mine communication systems
	Signals and signaling
	Mine safety
Link:	https://hdl.handle.net/2027/mdp.39015078515270