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Colorado Creek

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

Geologic information

Identification information

Deposit ID 10308973
MRDS ID A015007
Record type Site
Current site name Colorado Creek
Related records 10233749, 10002572

Geographic coordinates

Geographic coordinates: -156.01081, 63.57186 (WGS84)
Relative position Colorado Creek is a large, generally northwest-flowing tributary to Hunch Creek. Tailings are shown on the U.S. G. S. Ophir C-1 topographic map (1954) for approximately 2 miles along Colorado Creek; the coordinates correspond to the approximate midpoint of these tailings, which is in sec. 20, T. 22 S., R. 15 E., Kateel River Meridian. Colorado Creek also flows in the Medfra C-6 quadrangle; see also MD014. Colorado Creek is locality 9 of Cobb (1972 [MF 367]). This 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
Silver Secondary

Materials information

Materials Type of material
Coulsonite Ore
Gold Ore
Ilmenite Ore
Magnetite Ore
Powellite Ore
Scheelite Ore
Stibnite Ore
Xanthoconite Ore

Mineral occurrence model information

Model code 119
USGS model code 39a
Deposit model name Placer Au-PGE
Mark3 model number 54

Nearby scientific data

(1) -156.01081, 63.57186
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The rocks in the vicinity of Colorado Creek are Cretaceous sandstone and conglomerate of the Kuskokwim group and altered volcanic rocks (Bundtzen and others, 1987). The gravel in the creek consists primarily of granitic rocks and chert (Mertie, 1936). The gravel is about 8 feet thick and buried under 10-20 feet of muck (Eakin, 1914; Mertie, 1936). A 6.5-mile-long paystreak extends along Colorado Creek from the Cripple Creek Mountains. This paystreak crosses into the Medfra C-6 quadrangle for approximately 2 miles and then returns to the Ophir quadrangle. Placer gold was recovered during large, non-float operations that also mined several feet of bedrock (Mertie, 1936; Cobb, 1973 [B 1374]). The fineness of the +10 mesh gold in Colorado Creek is 909.6, with 82.8 parts silver, and 2.57 parts impurities. The -8 to +14 mesh gold is 900.2 fine, with 91.8 parts Ag, and 8.15 parts impurities (Bundtzen and others, 1987). Heavy minerals found in concentrates from the Rosander Mining Co. placers include magnetite, ilmenite, coulsonite, anthophyllite, samarskite, powellite, and xanthoconite. An estimated 50% of the concentrate is magnetite; some platinum is reported in gold bullion (Bundtzen and others, 1987). Roehm (1937) reports the presence of scheelite and stibnite at Colorado Creek. The gold at Colorado Creek may be derived from Cretaceous or Tertiary meta-aluminous, alkali-calcic to quartz-alkalic monzonite plutons that are located nearby (Bundtzen and others, 1987), with local contributions from quartz-stibnite veins (see OP032), and mineralized fault zones and epithermal systems (see OP031). Mining along Colorado Creek began in 1913 (Eakin, 1913) and continues to the present (2001) . Colorado Creek has consistently been one of the largest placer mines in the area and has been active nearly continuously with documentation of mining in 1913, 1915, 1924, 1930, 1935, 1937, 1939, 1940, 1950, and from 1979 to the present (Eakin, 1913; Mertie and Harrington, 1916; Smith, 1933; Smith, 1937; Roehm, 1937; Smith, 1941; Smith, 1942; Bundtzen and others, 1992). Both creek and bench placers of Colorado Creek have been mined (Cobb, 1973 [B 1374]). A conservative estimate of the total production for Colorado Creek is 110,000 ounces of gold and 4,644 ounces of silver (Bundtzen, 1999). Also see OP005 and OP031-033, and MD014 (in the Medfra quadrangle).
  • Age = The Colorado Creek placer deposit is middle Pleistocene, based on isotopic dates from overburden and geological inference (Bundtzen and others, 1987; Thorson and Guthrie, 1992). The source of the placer gold may be the Cretaceous or Tertiary meta-aluminous, alkali-calcic to quartz-alkalic monzonite plutons that are located nearby (Bundtzen and others, 1987).

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 = A conservative estimate of production from Colorado Creek is 110,000 ounces of gold (Bundtzen, 1999).

Comments on the workings information

  • Workings / Exploration = Mining began in 1913 and continues to the present 2001). Colorado Creek has consistently been one of the largest placer mines in the district. Mining at Colorado Creek may be nearly continuous. Reports exist of mining in 1913, 1915, 1924, 1930, 1935, 1937, 1939, 1940, 1950, and from 1979 to the present (Eakin, 1913; Mertie and Harrington, 1916; Smith, 1933; Smith, 1937; Roehm, 1937; Smith, 1941; Smith, 1942; Bundtzen and others, 1992). Both creek and bench placers of Colorado Creek have been mined (Cobb, 1973 [B 1374]). The first mechanized mining along Colorado Creek was prior to World War II, when Sidney Paulson began mining with a dragline. The Fullerton brothers (Colorado Creek Mining Co.) mined Colorado Creek from about 1950 until about 1957 (Ron Rosander, oral commun., 2001). In 1983, a woolly mammoth skeleton was found at Colorado Creek; Rosander Mining Co. donated the skeleton to the University of Alaska Museum. Rosander Mining Co. has worked the ancestral channels of Colorado Creek's right bench since 1979 (Bundtzen and others, 1992). Additional exploration of the Colorado Creek area, including soil sampling, took place during the summer of 1998.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Bundtzen and others, 1987

General comments

Subject category Comment text
Deposit Model Name = Placer Au (Cox and Singer, 1986; model 39a)
Deposit Other Comments = For more information on Colorado Creek, contact the current claim owner, 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.