Eldorado Creek (tributary of Colorado Creek)

The Eldorado Creek (tributary of Colorado Creek) is a gold 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: Eldorado Creek (tributary of Colorado Creek)

Commodity

Primary: Gold

Location

State: Alaska
District: Innoko

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

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

Physiography

Not available

Mineral Deposit Model

Model Name: Placer Au-PGE
Model Name: Skarn Fe

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Rocks adjacent to the monzonite are hornfelsed, with local development of garnet- and magnetite-bearing skarn in calcareous volcanic and sedimentary rocks (Avalon Development Corp., 1998; S. Dashevsky, 2001, oral commun.).

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Magnetite
Ore: Gold
Gangue: Quartz
Gangue: Garnet

Comments

Comment (Geology): Age = Placer deposits along nearby Colorado Creek area are middle Pleistocene, based on isotopic dates from overburden and geological inference (Bundtzen and others, 1987; Thorson and Guthrie, 1992). The skarn deposits are Cretaceous or younger.

Comment (Reference): Primary Reference = Duncan, 1999

Comment (Workings): Workings / Exploration = Prior to World War II, placer mining was conducted by William Critchley along the lower portion of Eldorado Creek, and William (Billy the Greek) Senatikis mined the upper portion (Ron Rosander, oral commun., 2001). The Strandberg family mined on Eldorado Creek in the 1950's and Mr. Nerod mined in the 1970's (McGinnis, 1997). During 1994, 1995, and 1996, claimholder Ron Rosander contracted geologist James Barker to evaluate the lode sources of placer gold in the Colorado Creek area. Barker collected 254 soil samples, 93 rock samples, and 12 samples of placer gold for scanning-electron microscope and trace element analysis. Geologic mapping and a ground-based magnetometer survey were also carried out (Barker, 1996; McGinnis, 1997). In 1996, the Alaska Division of Geological and Geophysical Surveys conducted geologic mapping in the Cripple Creek Mountains and Placer Dome Exploration flew an east-west-oriented aeromagnetic survey over the Cripple Creek Mountains. Nova Gold conducted geologic mapping, rock sampling, and soil sampling during the summer of 1998 (Avalon Development, 1998). During 1999, Poseidon Minerals, Ltd. carried out soil sampling in the Colorado Creek area, and used mobile-metallic-ion (MMI) analyses (Duncan, 1999).

Comment (Deposit): Model Name = Placer Au (Cox and Singer, 1986; model 39a) and Skarn (Cox and Singer, 1986; model 18d)

Comment (Deposit): Model Number = 39a; 18d

Comment (Deposit): Other Comments = For more information on Eldorado Creek, contact Ron Rosander in McGrath, AK.

Comment (Geology): Geologic Description = The rocks in the vicinity of Eldorado Creek consist of intermediate to mafic volcanic and volcaniclastic rocks, and of Cretaceous Kuskokwim Group black shale, limestone, graywacke, and conglomerate intruded by Cripple Mountain monzonite (McGinnis, 1997; Avalon Development Corp., 1998; Duncan, 1999). The rocks adjacent to the monzonite are hornfelsed, with local development of garnet- and magnetite-bearing skarn in calcareous volcanic and sedimentary rocks (Avalon Development Corp., 1998; S. Dashevsky, oral commun., 2001). Extensive placer mining was carried out along El Dorado Creek for about one mile upstream from its junction with Colorado Creek. Tailings in the upper part of Eldorado Creek do not follow the modern streambed and extend to the western walls of the stream drainage up to the flanks of Porphyry Knob (OP031) (S. Dashevsky, oral commun., 2001). Placer mining on Eldorado Creek was conducted by the Strandberg family in the 1950's and by Mr. Nerod in the 1970's (McGinnis, 1997). Production figures for Eldorado Creek are not available (see OP002; and in the Medfra quadrangle, MD014, for Colorado Creek drainage production figures). Also see OP002, 031, and 032; and in the Medfra quadrangle, MD014.

Comment (Exploration): Status = Active

References

Reference (Deposit): Dashevsky, S.S., 2000, Colorado Creek project (Au) Innoko district, Alaska: unpublished report for Rosander Mining Company, 7 p.

Reference (Deposit): Duncan, R.G., 1999, Colorado Creek project, Alaska, interim report: unpublished report for Poseidon Minerals Ltd., 22 p.

Reference (Deposit): McGinnis, M.F., McCoy, M.E., Nerup, M.R., and Barnett, D., 1997, Colorado Creek project Alaska, 1997 summary report: unpublished Placer Dome Exploration Inc. report, 37 p.

Reference (Deposit): Avalon Development Corp., 1998, Colorado Creek project, Ophir and Medfra quadrangles, southwest Alaska: report prepared for NovaGold Resources Inc., 9 p.

Reference (Deposit): Thorson, R.M., and Guthrie, R.D., 1982, Stratigraphy of the Colorado Creek mammoth locality, Alaska: Quaternary Research, v. 37, no. 2, p. 214-228.

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