What the coal miners can do to prevent injury from falls of roof

Author:	Paul, J. W.
Year:	1930
Document Type:	MAIN
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	C 22.11:6315
Series:	Information circular / U.S. Bureau of Mines ;
Report Number:	6315
Subjects:	Coal mines and mining
	Mine safety
	Coal mine accidents
Link:	https://hdl.handle.net/2027/mdp.39015095084367