Colorado Creek

Producer in Alaska, United States with commodities Silver, Gold, Mercury, Palladium, Antimony, Uranium

Geologic information

Identification information

Deposit ID 10107524
MRDS ID A012433
Record type Site
Current site name Colorado Creek
Related records 10282124

Geographic coordinates

Geographic coordinates: -155.99995, 63.61252 (WGS84)
Relative position This placer mine is situated in Colorado Creek basin above the junction of Creston Creek; the center of the placer is at an elevation of 550 feet (167 m) in Section 5, T. 22 S., R. 15 E., of the Kateel River Meridian. The site is accurately located; the reporter worked at the site in 1996.
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Geographic areas

Country State
United States Alaska


Commodity Importance
Silver Primary
Gold Primary
Mercury Secondary
Palladium Secondary
Antimony Secondary
Uranium Secondary

Comments on the commodity information

  • Ore Material = samarskite
  • Ore Material = xanthoconite
  • Ore Material = palladium (trace)
  • Ore Material = palladium (trace)

Materials information

Materials Type of material
Coulsonite Ore
Gold Ore
Powellite Ore
Palladium Ore
Samarskite Ore
Xanthoconite Ore
Garnet Gangue
Ilmenite Gangue
Magnetite Gangue

Mineral occurrence model information

Model code 119
USGS model code 39a
BC deposit profile C01. C02
Deposit model name Placer Au-PGE
Mark3 model number 54

Host and associated rocks

  • Host or associated Host
    Rock type Unconsolidated Deposit > Gravel

Nearby scientific data

(1) -155.99995, 63.61252

Comments on the geologic information

  • Geologic Description = The Colorado Creek gold-polymetallic placer deposit in the Medfra quadrangle is a portion of a 6.5 mile (10.4 km) long auriferous placer paystreak originating in the Cripple Creek Mountains. The payzone in the Medfra C-6 quadrangle comprises about 2.0 miles (3.2 km) or 30 percent of the total commercially exploited deposit. The auriferous gravels in the lower end average about 16 feet (5 m) thick and have an average width of 800 feet (243 m). The east limit of the paystreak gradually turns into an elevated ancestral bench overlain by up to 40 feet (12 m) of mixed eolian and colluvial deposits of Illinoin and Wisconsin age. The overburden contains well preserved Pleistocene megafauna which has been excavated by University of Alaska-Fairbanks Museum personnel (Thorson and Guthrie, 1982). ? the gravels in Colorado Creek paystreak contain abnormally high concentrations of boulders up to 3 feet (0.9 m) in diameter derived from the Cripple Creek Mountains. This, coupled with knowledge that the Cripple Creek Mountains were glaciated in Quaternary time, suggests a glaciofluvial outwash origin for the placer deposits (Bundtzen and others, 1997). ? Gold in Colorado Creek averages 873 fine with 121 silver. Anomalous mercury (up to 2.02 percent) was detected in some placer gold. An unusual group of rare heavy minerals were identified from mine concentrates, including traces of palladium, the niobium-uranium-yttrium mineral samarskite, the vanadium mineral coulsonite, and the silver sulfosalt xanthoconite (Bundtzen and others, 1987). In addition, an abnormally high concentration of garnet-magnetite-tactie cobbles have been recovered in cleanups, presumably derived from mineralization at the Neirod-East prospect (MD020).
  • Age = Middle Pleistocene, based on isotopic dates from overburden and geological inference (Bundtzen and others, 1997; Thorson and Guthrie, 1982).

Economic information

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic

Comments on exploration

  • Status = Active

Mining district

District name Innoko

Comments on the production information

  • Production Notes = The first reported gold production from Colorado Creek occurred in 1913, when O. A. Olsen mined from a shaft near Creston Creek on a small scale (Bundtzen and others, 1997). After World War I, production was intermittent until 1928, when Sid Paulsen initiated a hydraulic mining venture. Dragline-bulldozer equipment was introduced in 1937. Mining continued on a small scale during World War II. From 1949 to 1958, Fullerton Brothers Mining Inc. and Strandberg and Sons Mining Inc. conducted large scale dragline-bulldozer operations in two locations on the creek. The Fullertons worked on the lower end mainly in the Medfra quadrangle. Mine activities ceased by 1960s. Beginning in 1974, Rosander Mining Company acquired most of the claims in the Colorado Creek basin and initiated medium scale dragline-bulldozer operations, which continues to the present day. Based on researching past mining records, Bundtzen and others (1997) estimate that approximately 110,000 ounces (3,421 kg) of gold and 12,500 ounces (388 kg) of silver were produced in Colorado Creek from 1913 to 1997. About 30 percent of this total came from the portion of the deposit within the Medfra C-6 quadrangle.

Comments on the workings information

  • Workings / Exploration = Almost all past production has been from surface workings. Prior to 1915, some shafts were driven near the junction of Colorado Creek with Creston Creek. Beginning in 1930, hydraulic mine operations predominated, and from the late 1930s to the present, dragline-bulldozer have predominated. Hydraulic boom-dam methods proved to be very successful in previous years. ? From 1946 to 1948, the Goodnews Bay Mining Company conducted an extensive churn drilling program on Colorado Creek in anticipation of proving up a reserve that could be mined by a bucket line dredge. The company terminated the project and judged it was not suitable for a dredge. (John Fullerton, 1998). In recent years, the payzone has averaged about 0.015 ounces gold per cubic yard of pay (Ron Rosander, written communication, 1997).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012433
USGS Alaska Resource Data File ARDF MD014

Bibliographic references

  • Deposit

    Mertie, J.B., Jr., 1936, Mineral deposits of the Ruby-Kuskokwim region, Alaska: U.S. Geological Survey Bulletin 864-C, 115-245.

  • Deposit

    Patton, W.W., Jr., Moll, E.J., Dutro, J.T., Jr., Silberman, M.L., and Chapman, R.M., 1980, Preliminary geologic map of Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811-A, 1 sheet, scale l:250,000.

  • Deposit

    Thorson, R.M., and Guthrie, R.D., 1982, Stratigraphy of the Colorado Creek Mammoth locality, Alaska: Quaternary Research, vol. 37, p. 214-278.

  • Deposit

    Bundtzen, T.K., Pinney, D.S., and Laird, G.M., 1997, Preliminary geologic map and descriptive data tables from the Ophir C-1 and western Medfra C-6 quadrangles, Alaska: Alaska Division of Geological and Geophysical Surveys Public Data File Report 97-46, 10 p., 1 sheet, scale 1:63,360.

Comments on the references

  • Primary Reference = Bundtzen and others, 1997

General comments

Subject category Comment text
Deposit Model Name = Placer Au-PGE deposits (Cox and Singer, 1986; model no. 39a)
Deposit Other Comments = See Neirod-East (MD020), Montana Saddle (MD018), and Montana Creek (MD015) prospects.

Reporter information

Type Date Name Affiliation Comment
Reporter 04-JUN-98 Bundtzen, T.K. Pacific Rim Geological Consulting