Prospecting and exploration for sand and gravel

Author:	Thoenen, J. R.
Year:	1932
Document Type:	USBI
Issuing Agency:	U.S. Dept. of Commerce, Bureau of Mines,
SUDOC:	C 22.11:6668
Series:	Information circular / Bureau of Mines ;
Report Number:	6668
Subjects:	Prospecting--Geophysical methods
	Sand and gravel mines and mining
Link:	https://hdl.handle.net/2027/mdp.39015086485797