Methods and costs of sinking a circular concrete-lined ventilation shaft

Author:	Williams, Lloyd.
Year:	1960
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines :
SUDOC:	I 28.27:7955
Series:	Information circular / United States Department of the Interior, Bureau of Mines ;
Report Number:	7955
Subjects:	Iron mines and mining--Alabama--Jefferson County
	Shaft sinking
	Mine ventilation
Link:	https://hdl.handle.net/2027/mdp.39015078460790