Accidents from falls of rock or ore in metal mines

Author:	Denny, E. H.
Year:	1940
Document Type:	MAIN
Issuing Agency:	U.S. Govt. Print. Off.,
Series:	Miners' circular ;
Report Number:	41
Subject:	Mine accidents--United States
Link:	https://hdl.handle.net/2027/mdp.39015077562299