Chip-Loy

The Chip-Loy is a nickel, cobalt, 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: Chip-Loy

Commodity

Primary: Nickel
Primary: Cobalt
Primary: Copper
Secondary: Silver
Secondary: Iron
Secondary: Gold

Location

State: Alaska
District: McGrath

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

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

Physiography

Not available

Mineral Deposit Model

Model Name: Synorogenic-synvolcanic Ni-Cu

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Slight oxidation of massive sulfides.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Bravoite
Ore: Chalcopyrite
Ore: Pentlandite
Ore: Sphalerite
Ore: Tetradymite
Ore: Cubanite
Ore: Galena
Ore: Violarite
Gangue: Ilmenite

Comments

Comment (Reserve-Resource): Reserves = Herreid (1968), who provides the only detailed geologic map of the Chip-Loy deposit, estimated that approximately 150,000 tonnes of disseminated-to- massive sulfide mineralization exists on site. Smith and Albanese (1985) estimate that between 0.15 and 1.25 million tonnes of disseminated to massive mineralization exist at the Chip-Loy deposit.

Comment (Workings): Workings / Exploration = The Chip-Loy deposit was discovered and staked by prospectors Ed Chipp and Robert Loy in the early 1960s. Surface samples have been collected and analyzed by Herreid (1968), Bundtzen, Roberts, and others (1982), Smith and Albanese (1985), Roberts (1985), Gilbert and others (1988), Foley (1987), and T.K. Bundtzen and G.M. Laird (written communication, 1998). Chip-channel sample intervals from the Chip-Loy deposit run up to 3.30 percent nickel, 0.25 percent cobalt, 2.10 percent copper, 12.1 grams/tonne silver, and 43.2 percent iron. A 12 meter-long, chip-channel sample taken across the strike of the mineralized zone contained 0.70 percent nickel, 444 ppm cobalt, 0.25 percent copper, 2.6 grams/tonne silver, and 17.82 percent iron (Smith and Albanese, 1985; Gilbert and others, 1988).

Comment (Geology): Age = Unknown; thought to be early Tertiary by Gilbert and others (1988).

Comment (Commodity): Ore Material = undetermined Co-Ni-Fe arsenide

Comment (Deposit): Model Name = Gabbroic Ni-Cu (Cox and Singer, 1986; model 7a).

Comment (Deposit): Other Comments = About 50 percent of the nickel and cobalt is believed to exist in pyrrhotite; the remainder is in pentlandite and other nickleiferous and cobaltiferous minerals.

Comment (Exploration): Status = Inactive

Comment (Reference): Primary Reference = Herreid, 1968

Comment (Geology): Geologic Description = According to Herreid (1968), Foley (1987), Nokleberg and others (1987), and Foley and others (1997), the Chip-Loy deposit consists of an irregular, steeply dipping layer of massive to disseminated, nickelian pyrrhotite accompanied by other sulfides in an elongate, composite, diabase intrusion. Herreid (1968) describes the diabase, which ranges from gabbro to diorite, as a pipe in plane view, but Smith and Albanese (1985) describe the same intrusion as a dike. The diabase trends in a northeast direction and varies from 40 meters to 260 meters wide; cliff walls prevent accurate investigations of the intrusion's true dimensions. The composite diabase intrusion cuts mid-Silurian Terra Cotta Mountains Sandstone, a formation of the Dillinger subterrane, a continental margin assemblage of Lower Paleozoic age. (Bundtzen, Harris, and Gilbert, 1997). Although undated, Gilbert and others (1988) assign the mineralized diabase intrusion an early Tertiary age.? the Chip-Loy deposit contains disseminated-to-massive sulfides, mainly pyrrhotite and chalcopyrite, and minor cubanite, and sphalerite, and trace galena, bravoite, violarite, tetradymite (Bi2Te2S), and undetermined Co-Ni-Fe arsenides (Bart Cannon, written communication, 1998). The sulfides are interwoven with ilmenite and other rock-forming minerals such as plagioclase and olivine. The northeast trending, sulfide-bearing zone occurs within the diabase about 10 to 30 meters away from the contact with sandstone and shale. The zone is about 335 meters long and 10 to 15 meters wide, but is quite irregular along strike. Herreid (1968) estimated that the Chip-Loy deposit contained an inferred reserve of about 150,000 tonnes of disseminated and massive sulfide mineralization. Smith and Albanese (1985) suggested a larger reserve than Herreid; they estimate from 0.15 to 1.25 million tonnes of sulfide mineralization exist at the Chip-Loy deposit. ? Chip-channel samples from the Chip-Loy deposit contain up to 3.30 percent nickel, 0.25 percent cobalt, 2.10 percent copper, 12.1 grams/tonne silver, and 43.2 percent iron (Smith and Albanese, 1985; Bundtzen, Roberts, and others, 1982). A single sample of massive sulfide mineralization contained 3.0 grams/tonne gold (Foley, 1987; Gilbert and others, 1988). Tetradymite was found in solid solution with rock-forming silicates--a typical PGE association--although no PGE has ever been detected in analyses of mineralized rock from the Chip-Loy deposit. A 12-meter-long chip-channel sample taken midway across the strike of the deposit contained 0.28 percent copper, 2.6 grams/tonne silver, 444 ppm cobalt, 0.70 percent nickel, and 17.82 percent iron (Smith and Albanese, 1985; Gilbert and others, 1988). Pyrrhotite from selected samples averages 0.4 percent cobalt and 1.5 percent nickel (Bart Cannon, written communication, 1998).

Comment (Commodity): Ore Material = violarite

Comment (Commodity): Ore Material = nickelian pyrrhotite

References

Reference (Deposit): Smith, T.E., and Albanese, M.D., 1985, Preliminary prospect examinations in the McGrath B-2, A-3, and A-4 quadrangles, Alaska: Alaska Division of Geological and Geophysical Surveys Public Data File 85-54, 19 pages.

Reference (Deposit): Gilbert, W.G., Solie, D.N., and Kline, J.T., 1988, Geologic map of the McGrath A-3 quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Professional Report 92, 2 sheets, 1:63,360 scale.

Reference (Deposit): Foley, J.Y., 1987, Reconnaissance strategic and critical mineral investigations in the McGrath A-3 and B-2 quadrangles, southwest Alaska: U.S. Bureau of Mines Field Report, 26 pages.

Reference (Deposit): Foley, J.Y., Light, T.D., Nelson, S.W., and Harris, R.A., 1997, Mineral occurrences associated with mafic-ultramafic and related alkaline complexes in Alaska: Economic Geology, Monograph 9, p. 396-449.

Reference (Deposit): Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, D.J., Robinson, M.S., Smith, T.E., and Yeend, W., 1987, Significant metalliferous lode deposits and placer districts of Alaska: U.S. Geological Survey Bulletin 1786, 104 p.

Reference (Deposit): Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-485, 101 p.

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the McGrath quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-379, 1 sheet, 1:250,000 scale.

Reference (Deposit): Herreid, G.H., 1968, Geological and geochemical investigations southwest of Farewell, Alaska: Alaska Division of Mines and Geology Geologic Report 26, 24 p., 1 sheet, scale 1:75,000.

Reference (Deposit): Bundtzen, T.K., Kline, J.T., and Clough, J.G., 1982, Preliminary geologiy of the McGrath B-2 quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Open-File report 149, 22 p., 1 sheet, scale 1:40,000.

Reference (Deposit): Bundtzen, T.K., Harris, E.E., and Gilbert, W.G., 1997, Geologic Map of the eastern McGrath quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 97-14, 34 p., 1 sheet, scale 1:125,000.

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