Mine Safety Board decision 30 :main fan installations at coal mines

Year:	1939
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7050
Series:	Information circular / Bureau of Mines ;
Report Number:	7050
Subjects:	Coal mines and mining--Safety measures
	Mine ventilation
Link:	https://hdl.handle.net/2027/mdp.39015077575515