Mine Safety Board decision 28 :safety catches and arresting devices for cages, skips, and cars in mine shafts and slopes

Year:	1938
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7002
Series:	Information circular / Bureau of Mines ;
Report Number:	7002
Subjects:	Mine safety
	Mine shafts
Link:	https://hdl.handle.net/2027/mdp.39015077575705