Accidents from falls of roof and coal in bituminous-coal mines :coal-mine accident-prevention course.

Year:	1945
Document Type:	MAIN
Issuing Agency:	U.S. G.P.O.,
SUDOC:	I 28.6:48
Series:	Miner's circular ;
Report Number:	48
Subjects:	Mine roof control--United States
	Coal mine accidents--United States--Prevention
Link:	https://hdl.handle.net/2027/mdp.39015077562497