Mine signboards

Author:	Higgins, Edwin.
Additional Authors:	Steidle, Edward,
Year:	1913
Document Type:	USBM
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.7:67
Series:	Technical paper / United States Department of the Interior, Bureau of Mines ;
Report Number:	67
Subjects:	Signs and signboards
	Coal mines and mining--Safety measures
Link:	https://hdl.handle.net/2027/mdp.39015077560921