Stop, look and listen! :the roof is going to fall

Author:	Paul, J. W.
Year:	1927
Document Type:	USBI
Issuing Agency:	U.S. Dept. of Commerce, Bureau of Mines,
SUDOC:	C 22.11:6032
Series:	Information circular / United States Department of Commerce, Bureau of Mines ;
Report Number:	6032
Subjects:	Mine timbering
	Coal mines and mining--Safety measures
	Mining engineering
Link:	https://hdl.handle.net/2027/mdp.39015086415364