Natural Ventilation of Michigan Copper Mines

Author:	McElroy, G. E.
Year:	1932
Document Type:	N/A
SUDOC:	C 22.5:516
Series:	Technical paper (United States. Bureau of Mines) ; 516
Report Number:	Technical Paper 516
Subjects:	Mine ventilation.
	Copper mines and mining -- Michigan.
Link:	http://digital.library.unt.edu/ark:/67531/metadc66391/