Economies through roof bolting in an Indiana coal mine

Author:	Kelly, L. W.
Year:	1952
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7653
Series:	Information circular / United States. Bureau of Mines ;
Report Number:	7653
Subjects:	Mine roof bolting
	Coal mines and mining--Indiana
Link:	https://hdl.handle.net/2027/mdp.39015078456624