Grubstake Creek

Past Producer in Alaska, United States with commodities Gold, Silver, Copper

Geologic information

Identification information

Deposit ID 10001151
MRDS ID A011847
Record type Site
Current site name Grubstake Creek
Related records 10282705

Geographic coordinates

Geographic coordinates: -144.05152, 62.78468 (WGS84)
Relative position Grubstake Creek (Cobb, 1979 [OF 79-1247 p. 11-12] flows west and joins Ahtell Creek about 2 miles south of the Dome. The creek was mainly mined in a section of its canyon about 0.8 to 1.2 miles above its mouth. Grubstake Creek is locality 10 of Richter (1966), locality 17 of Richter and Matson (1972), and locality 16 of MacKevett and Holloway (1977). The location is accurate to within 500 feet; it is in the SE1/4SW1/4, section 26, T. 12 N., R. 7 E., Copper River Meridian.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Silver Secondary
Copper Secondary

Materials information

Materials Type of material
Copper Ore
Gold Ore
Silver Ore
Ilmenite Gangue
Magnetite Gangue

Alteration

  • (Local) Rocks nearby have iron-stained, pyrite-rich zones and and there is local hydrothermal alteration of the Ahtell pluton and its wall rocks.

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

Nearby scientific data

(1) -144.05152, 62.78468

Comments on the geologic information

  • Geologic Description = The rocks along Grubstake Creek consist of granitic rocks of the Pennsylvanian to Permian, Ahtell pluton and altered volcanics and minor sedimentary rocks of the Pennsylvanian to Permian,Tetelna Formation. Jurassic diorite forms small bodies that intrude the volcanic section and possibly the Ahtell pluton. Richter and Matson (1968) proposed that the source of the placer was the Jurassic diorite; earlier Richter (1966) had assumed that the source was the Permian, Ahtell intrusive.? the placer deposit consisted of poorly sorted gravels with occasional boulders. The discovery of an economic placer was made in 1934. The gravel section reported then was more than 16 feet thick and bedrock had not been reached (Moffit, 1936, p. 139-141). The country rock was volcanic and limestone with Permian fossils. Native gold was accompanied by significant amounts of native copper and native silver. The native metals found in the placer, are rough and some are dendritic, indicating a local source. Ilmenite was found in concentrates, and magnetite occurred locally in flattened slabs more than 1 foot across. Moffit (1937, p. 106-107) later reported that sheared diorite was encountered in bedrock under the placer.
  • Age = Holocene placer .

Economic information

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Chistochina

Comments on the production information

  • Production Notes = Placer deposits in Grubstake and Slope Creeks (GU007) have been mined intermittently since 1934. The total gold production from both creeks is probably less than $30,000 (about 857 ounces) (Richter and Matson, 1968).

Comments on the workings information

  • Workings / Exploration = Gold was found in sub-economic concentrations early in the history of the district. An economic deposit was found in 1934 and was mined on at least a small scale until World War II (Moffit, 1936, 1937,1938; Smith, 1942; Moffit, 1942; Thorne, 1946). It was subsequently worked on a small scale after the war.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A011847
USGS Alaska Resource Data File ARDF GU017

Bibliographic references

  • Deposit

    Moffit, F.H., 1936, Upper Copper and Tanana Rivers: U.S. Geological Survey Bulletin 868, p. 135-143.

  • Deposit

    Moffit, F.H., 1937, Recent mineral developments in the Copper River region: U.S. Geological Survey Bulletin 880, p. 97-109.

  • Deposit

    Moffit, F.H., 1944, Mining in the northern Copper River region, Alaska: U.S. Geological Survey Bulletin 943, p. 25-47.

  • Deposit

    Thorne, R.L., 1946, Exploration of argentiferous lead-copper deposits of the Slana district, Alaska: U.S. Bureau of Mines Report of Investigations 3940, 9 p.

  • Deposit

    Richter, D.H., 1966, Geology of the Slana district on south-central Alaska: Alaska Division of Geological and Geophysical Surveys Geological Report 2l, 36b p., 3 sheets, scale 1:63,360.

  • Deposit

    Richter, D.H., and Matson, N.A., 1968, Distribution of gold and some base metals in the Slana area, eastern Alaska Range, Alaska: U.S. Geological Survey Circular 593, 20 p.

  • Deposit

    Cobb, E.H., 1979, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Gulkana quadrangle, Alaska: U.S. Geological Survey Open-File Report 79-1247, 36 p.

  • Deposit

    Nokleberg, W.J., and others, 1994, Metallogeny and major mineral deposits of Alaska and Metallogenic map of significant metalliferous lode deposits and placer districts of Alaska, in Plafker, G. and Berg, H.C., eds., The Geology of Alaska: Boulder, Colorado, Geological Society of America: The Geology of North America, v. G1, p. 855-904 and v. G1, Plate 11, scale 1:2,500,000.

  • Deposit

    MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.

  • Deposit

    Moffit, F.H., 1938, Geology of the Slana-Tok district, Alaska: U.S. Geological Survey Bulletin 904, 54 p.

  • Deposit

    Smith, P.S., 1942, Mineral industry of Alaska in 1940: U.S. Geological Survey Bulletin 933-A, p. 1-102.

  • Deposit

    Richter, D.H., and Matson, N.A., Jr., 1972, Metallic mineral resources map of the Gulkana quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-419, 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Richter, 1966; Richter and Matson, 1968

General comments

Subject category Comment text
Deposit Model Name = Placer Au (Cox and Singer, 1986; model 39a)
Deposit Other Comments = See also Slope Creek (GU020). The placer in upper Grubstake Creek probably overlies a disseminated lode gold deposit (GU019).

Reporter information

Type Date Name Affiliation Comment
Reporter 20-DEC-00 W.T. Ellis Alaska Earth Sciences
Reporter 20-DEC-00 Hawley, C.C. Hawley Resource Group
Reporter 20-DEC-00 W.J. Nokleberg U.S. Geological Survey