1. Mineral Resources
  2. Online Spatial Data
  3. Mineral Resource Data System (MRDS)

Eldorado Creek (tributary of Colorado Creek)

Producer in Alaska, United States with commodity Gold
Map
XML
JSON
KML
B
Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Mineral occurrence model information
  9. Nearby scientific data
  10. Economic information about the deposit and operations
  11. Mining district
  12. Links to other databases
  13. Bibliographic references
  14. General comments
  15. Reporter information

Geologic information

Identification information

Deposit ID 10308033
Record type Site
Current site name Eldorado Creek (tributary of Colorado Creek)

Geographic coordinates

Geographic coordinates: -156.01361, 63.54736 (WGS84)
Relative position Eldorado Creek is a short, generally north-flowing headwater tributary to Colorado Creek. Placer mining on Eldorado Creek was an extension of mining on Colorado Creek. Placer tailings begin at the mouth of Eldorado Creek and continue for nearly 1 mile upstream. The coordinates are for the approximate midpoint of the lower group of tailings, in the southern half of sec. 29, T. 22 S., R. 15 E., Kateel River Meridian. The location is accurate.

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Ophir C-1(quadrangle 1:63,360 scale)

Ophir NE(quadrangle 1:100,000 scale)

Ophir(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary

Materials information

Materials Type of material
Gold Ore
Magnetite Ore
Garnet Gangue
Quartz Gangue

Alteration

  • (Local) 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.).

Mineral occurrence model information

Model code 119
USGS model code 39a
Deposit model name Placer Au-PGE
Mark3 model number 54
Model code 62
USGS model code 18d
Deposit model name Skarn Fe

Nearby scientific data

(1) -156.01361, 63.54736
ListMap

Economic information

Comments on the geologic information

  • 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.
  • 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.

Economic information about the deposit and operations

Development status Producer

Comments on exploration

  • Status = Active

Mining district

District name Innoko

Comments on the workings information

  • 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).

Reference information

Bibliographic references

  • 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.

  • 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.

  • Deposit

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

  • Deposit

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

  • Deposit

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

Comments on the references

  • Primary Reference = Duncan, 1999

General comments

Subject category Comment text
Deposit Model Name = Placer Au (Cox and Singer, 1986; model 39a) and Skarn (Cox and Singer, 1986; model 18d)
Deposit Model Number = 39a; 18d
Deposit Other Comments = For more information on Eldorado Creek, contact Ron Rosander in McGrath, AK.

Reporter information

Type Date Name Affiliation Comment
Reporter 07-AUG-01 Cameron, C.E. Northern Associates Inc.

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.