Isometric sketch of Calumet conglomerate lode

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• The Calumet Conglomerate Lode plunged almost 6000 feet beneath the surface along an outcropping that extended almost two miles long. By the time this sketch was drawn, this rich lode produced more than 40% of the native copper mined from the entire district (Dorr, Geology of Michigan, 1970).
2/19/2009 10:07:29 AM by Anonymous