Methods of development and pillar extraction in mining the Pittsburgh coal bed in Pennsylvania, West Virginia, and Ohio

Author:	Paul, J. W.
Additional Authors:	Plein, Leopold Nicholas,
Year:	1935
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:6872
Series:	Information circular / United States Department of the Interior, Bureau of Mines ;
Report Number:	6872
Subjects:	Coal mines and mining--Pennsylvania
	Mining engineering
	Coal mines and mining--West Virginia
	Coal mines and mining--Ohio
Link:	https://hdl.handle.net/2027/mdp.39015077568742