Rock-dust material for coal mines

Year:	1926
Document Type:	USBI
Issuing Agency:	U.S. Dept. of Commerce, Bureau of Mines,
SUDOC:	C 22.11:6009
Series:	Information circular / Bureau of Mines ;
Report Number:	6008
Subjects:	Coal mines and mining--Safety measures
	Mine explosions
Link:	https://hdl.handle.net/2027/mdp.39015086471276