Control of roof and prevention of accidents from falls of rock and coal :suggested roof supports for use at faces in conjunction with mechanical loading

Additional Authors:	Perz, Frank., Hansen, M.V., Thomas, Edward., Seeling, C.H.
Year:	1948
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7471
Series:	United States. Bureau of Mines. Information circular
Report Number:	7471.
Subjects:	Coal mines and mining--Safety measures
	Tunneling--Equipment and supplies
Link:	https://hdl.handle.net/2027/mdp.39015078463711