Sand and gravel excavation.

Author:	Thoenen, J. R.
Year:	1934
Document Type:	USBI
Issuing Agency:	U.S. Dept. of the Interior, Bureau of Mines,
SUDOC:	I 28.27:6798
Series:	Information circular / United States Department of the Interior, Bureau of Mines ;
Report Number:	6798
Subjects:	Gravel
	Sand
	Excavating machinery
Link:	https://hdl.handle.net/2027/mdp.39015077569195