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Please use this identifier to cite or link to this item: http://hdl.handle.net/11299/59299

Title: Information Circular 10. Copper and Nickel Resources in the Duluth Complex, Northeastern Minnesota
Authors: Bonnichsen, Bill
Keywords: geology
copper
Minnesota Geological Survey
nickel
Duluth Complex
northeastern Minnesota
Issue Date: 1974
Publisher: Minnesota Geological Survey
Series/Report no.: Information Circular
10
Abstract: The Ely-Hoyt Lakes region, in northeastern Minnesota, contains very large quantities of disseminated copper and nickel sulfides that are potentially minable. The principal sulfides are pyrrhotite, chalcopyrite, cubanite, and pentlandite, and the average copper-nickel ratio in the sulfide concentrations is approximately 3:1. The sulfides are associated with the northwestern margin of the Duluth Complex, a large mafic igneous pluton of Late Precambrian age, and occur principally within the basal zone of the intrusion. A conservative estimate of the metal resources in the Ely-Hoyt Lakes region, based on assay data available from 24 drill holes, and a cutoff grade, or lower mining limit, of 0.5 percent combined copper and nickel indicates 13.8 million tons of copper and 4.6 million tons of nickel having a gross value of $27 billion. Although the copper and nickel deposits in the Ely-Hoyt Lakes region are marginal economically, they constitute one of the United States' principal metal resources.
URI: http://purl.umn.edu/59299
Appears in Collections:Information Circulars

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