Relative pressure changes in coal pillars during extraction :a progress report

Author:	Curth, Ernest A.
Year:	1967
Document Type:	BMRA
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.23:6980
Series:	Report of investigations / United States Department of the Interior, Bureau of Mines ;
Report Number:	6980
Subjects:	Coal mines and mining
	Mining engineering
Link:	https://hdl.handle.net/2027/mdp.39015078532119