Shaft sinking by rotary drilling

Author:	Platt, D. H.
Year:	1945
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:7336
Series:	Information circular / United States Department of the Interior, Bureau of Mines ;
Report Number:	7336
Subjects:	Shaft sinking
	Rotary drilling
Link:	https://hdl.handle.net/2027/mdp.39015074127591