Mine detail: Isle Royale Mine

Previously called 'Old Isle Royale MineDodge Exploration Formation'

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Location

Lat / long:

47.09778, -88.58033

Resource(M)

Primary:	Copper
Secondary:	Silver
Ore:	Copper
Gangue:	Feldspar, Epidote, Quartz, Calcite, Sericite, Pumpellyite-(Mg)
Orebody form:	TABULAR

Production

Operation type:	Unknown
Deposit type:	Lode
Production size:	Medium
Development status:	Past Producer
Production years:	1853-1885; 1901-1925 AND POSSIBLY LATER.
First production started:	1853
Last production ended:	1885

Geology

Host rock:	Isle Royale Amygdaloid, Portage Lake Volcanics
Host type:	Basalt
Structure:	Syncline, Isle Royale syncline--the largest structure seen in the mine. The only fau
Alteration processes:	Early oxidation followed by epidotization/pumpellitization associated with copper mineralization

References

MRDS	W062231
DEP	10082868
Reference	{Deposit:: BUTLER, B.S., AND BURBANK, W.S., 1929, THE COPPER DEPOSITS OF MICHIGAN: USGS PROF PAPER NO. 144, 238 PP.}{Deposit:: WHITE, W.S., 1956, GEOLOGIC MAP OF THE CHASSELL QUADRANGLE, MICHIGAN: USGS MAP MF-43, SCALE 1:24000.}{Deposit:: JOHNSON, A.M. AND GROTH, E.H., 1998, INVENTORY OF UNDERGROUND MINES, HOUGHTON COUNTY, SITE ID 310016, MICHIGAN DEPARTMENT OF NATURAL RESOURCES.}{Production:: BUTLER, B.S., AND BURBANK, W.S., 1929, P. 87.}
Reporter	Sutphin, D.M. (Cannon, W.F.), Mason Jr., G.T., Anderson, Arlene (M. Gere)