Supervision as a means of preventing accidents from falls of roof and coal

Author:	Forbes, W. H.
Year:	1931
Document Type:	MAIN
Issuing Agency:	U.S. Dept of Commerce, Bureau of Mines,
SUDOC:	C 22.11:6434
Series:	Information circular / Bureau of Mines ;
Report Number:	6434
Subjects:	Coal mines and mining--Safety measures
	Coal mine accidents--Prevention
Link:	https://hdl.handle.net/2027/mdp.39015095085836