Backfilling problem in the anthracite region as it relates to conservation of anthracite and prevention of subsidence

Author:	Ash, S. H.
Additional Authors:	Westfield, James.
Year:	1946
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7342
Series:	Information circular / United States Department of the Interior, Bureau of Mines ;
Report Number:	7342
Subjects:	Coal mines and mining--Pennsylvania
	Mining engineering
	Anthracite coal--Pennsylvania
	Subsidences (Earth movements)
Link:	https://hdl.handle.net/2027/mdp.39015074127658