Mine Safety Board decision 31:main fan installations at metal mines

Year:	1939
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7078
Series:	Information circular / United States Department of the Interior, Bureau of Mines ;
Report Number:	7078
Subjects:	Metal mines and mining--Safety measures
	Mine ventilation
Link:	https://hdl.handle.net/2027/mdp.39015077570466