Two-leg longwall shield mechanics

Author:	Barczak, Thomas M.
Additional Authors:	Schwemmer, David E.
Year:	1989
Document Type:	BMRA
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.23:9220
Series:	Report of ivestigations / United States Department of the Interior, Bureau of Mines ;
Report Number:	9220
Subjects:	Longwall mining
	Mine roof control
Link:	https://hdl.handle.net/2027/mdp.39015078477166