Kennicott Mine

The Kennicott Mine is a silver and copper mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Kennicott Mine
Secondary: Erie
Secondary: Jumbo
Secondary: Bonanza
Secondary: Mother Lode

Commodity

Primary: Silver
Primary: Copper
Secondary: Zinc
Secondary: Lead

Location

State: Alaska
District: Nizina

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Model Name: Basaltic Cu (BC name is Volcanic redbed Cu)

Orebody

Not available

Structure

Not available

Alterations

Alteration Text: Oxidation of deposits is not related to present land surface. Practically entire deposit has been partially oxidized even in deepest levels of mine. Oxidized minerals are malachite, azurite, limonite, covellite, antlerite, chalcanthite, cuprite, Cu arsenates, brochantite (?).

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Chalcopyrite
Ore: Bornite
Ore: Azurite
Ore: Luzonite
Ore: Tennantite
Ore: Sphalerite
Ore: Malachite
Ore: Galena
Ore: Enargite
Ore: Covellite
Ore: Cinnabar
Ore: Chalcocite

Comments

Comment (Workings): Workings / Exploration = Mines located 4,000-6,000 ft elevation with over 700 mi in underground workings; lowest workings reached 2,800 ft elevation. Surface and underground workings.

Comment (Geology): Age = Cretaceous

Comment (Reference): Primary Reference = Bateman and McLaughlin, 1920

Comment (Geology): Geologic Description = Kennicott mines were renowned for the size and richness of their copper sulfide lodes. The largest known ore body (Jumbo Mine) consisting of almost pure chalcocite and covellite averaged 360 ft in height, was between 2 ft and 60 ft wide, and extended along its northeasterly plunge for 1,500 ft. Origin and geologic history of deposits is complex, obscure, and multiple hypotheses are still debated. Mainly chalcocite and covellite, with minor enargite, bornite, chalcopyrite, luzonite, and pyrite. Tennantite, sphalerite, and galena extremely rare. Local surface oxidation of sulfides to malachite and azurite. Sulfides occur mainly as large, irregular, massive, wedge-shaped bodies, mainly in dolomitic parts of the Upper Triassic Chitistone or Nizina Limestone. Generally less than 100 m above the Middle and(or) Upper Triassic Nikolai Greenstone. One of the most productive group of mines in Alaska from 1913 until 1938 when the ore was exhausted. More than 96 km of underground workings. Deposits interpreted by Armstrong and MacKevett (1982) as having formed by mobilization of Cu from the underlying Nikolai Greenstone and deposited by oxygenated groundwater and deposition in fossil karsts of a dolomitic sabkha interface in overlying limestone. Age of deposition interpreted as Cretaceous(?) with formation during regional low-grade metamorphism.

Comment (Exploration): Status = Inactive

Comment (Deposit): Model Name = Basaltic Cu

Comment (Production): Production Notes = Produced about 544 million kg Cu and 280 million g Ag from 4.3 million tonnes ore between 1913 and 1938. About 75 percent of ore mined was sulfide minerals of which 95 percent was chalcocite.

Comment (Deposit): Other Comments = Minor production in late 1960's from surface talus deposits.

References

Reference (Deposit): Bateman, A.M., and McLaughlin, D.H., 1920, Geology of the ore deposits of Kennecott, Alaska: Economic Geology, v. 15, p. 1-80.

Reference (Deposit): Miller, D.J., 1946, Copper deposits of the Nizina district, Alaska: U.S. Geological Survey Bulletin 947F, p. 93-120.

Reference (Deposit): MacKevett, E.M., Jr., 1970, Geologic map of the McCarthy C-5 quadrangle, Alaska: U.S. Geological Survey Geologic Quadrangle Map GQ-899, scale 1:63,360.

Reference (Deposit): MacKevett, E.M., Jr., 1976, Mineral deposits and occurrences in the McCarthy quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-773-B, scale 1:250,000.

Reference (Deposit): MacKevett, E.M., Jr., Albert, N.R.D., Barnes, D.F., Case, J.E., Robinson, Keith, and Singer, D.A., 1977, The Alaska Mineral Resource Assessment Program--Background information to accompany folio of geologic and mineral resource maps of the McCarthy quadrangle, Alaska: U.S. Geological Survey Circular 739, 23 p.

Reference (Deposit): Armstrong, A.K., and MacKevett, E.M., Jr., 1982, Stratigraphy and diagenetic history of the lower part of the Triassic Chitistone Limestone, Alaska: U.S. Geological Survey Professional Paper 1212-A, 26 p.

Reference (Deposit): Cobb, E.H., and MacKevett, E.M., Jr., 1980, Summaries of data on and lists of references to metallic and selected nonmetallic mineral deposits in the McCarthy Quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-885, 156 p.

Reference (Deposit): MacKevett, E.M., Jr., 1971, Stratigraphy and general geology of the McCarthy C-5 quadrangle, Alaska: U.S. geological Survey Bulletin 1323, 35 p.

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