Room and pillar retreat mining :a manual for the coal industry

Author:	Kauffman, Peter W.
Additional Authors:	Thompson, Robert R., Hawkins, Steven A.
Year:	1981
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:8849
Series:	Information circular / Bureau of Mines ;
Report Number:	8849
Subjects:	Coal mines and mining--Handbooks, manuals, etc
	Pillaring (Mining)--Handbooks, manuals, etc
Link:	https://hdl.handle.net/2027/mdp.39015078457325