Timber withdrawing and devices used for this purpose in some coal mines

Author:	Paul, J. W.
Additional Authors:	Calverley, Joseph Gladstone,
Year:	1933
Document Type:	USBI
Issuing Agency:	U.S. Dept. of Commerce, Bureau of Mines,
SUDOC:	C 22.11:6722
Series:	Information circular / United States Department of Commerce, Bureau of Mines ;
Report Number:	6722
Subjects:	Coal mines and mining
	Mine timbering
Link:	https://hdl.handle.net/2027/mdp.39015086485995