How to prevent death and injury from falls of roof in coal mines

Author:	Paul, J. W.
Year:	1932
Document Type:	MAIN
Issuing Agency:	U.S. Dept. of Commerce, Bureau of Mines,
SUDOC:	C 22.11:6570
Series:	Information circular / United States Department of Commerce, Bureau of Mines ;
Report Number:	6570
Subjects:	Coal mines and mining
	Coal mine accidents
Link:	https://hdl.handle.net/2027/mdp.39015095085554