Alder Gulch

Producer in Alaska, United States with commodities Silver, Gold, Bismuth, PGE, Antimony, Tungsten

Geologic information

Identification information

Deposit ID 10002606
MRDS ID A015043
Record type Site
Current site name Alder Gulch
Alternate or previous names Vinasale
Related records 10210148

Geographic coordinates

Geographic coordinates: -155.71291, 62.69556 (WGS84)
Relative position The Alder Gulch placer mine is located in Alder Gulch, a south flowing tributary that drains the south slope of Vinasale Mountain. The mine workings are at an elevation of 850 feet (259 m) in the NE1/4 sec. 18, T. 30 N., R. 34 W., of the Seward Meridian. The reporter investigated the mine in 1982.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Bismuth Secondary
PGE Secondary
Antimony Secondary
Tungsten Secondary

Materials information

Materials Type of material
Bismuth Ore
Gold Ore
Monazite Ore
Scheelite Ore
Ilmenorutile Ore

Alteration

  • (Local) Extensive oxidation of regolith results in grussification of plutonic suite.

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) -155.71291, 62.69556

Comments on the geologic information

  • Geologic Description = The Alder Gulch heavy mineral placer deposit consists of auriferous, semi-residual and alluvial, unconsolidated deposits of Quaternary age in a steep gulch on the south flank of Vinasale Mountain. The placer deposit lies down slope and downstream from a mineralized 69.0 Ma granitic pluton that forms most of Vinasale Mountain (Bundtzen, 1986). Alder Gulch has only intermittent water flow and is dry through much of late summer and fall. ? the gold and heavy mineral bearing material ranges from 0.5 to 2 meters thick, over stream widths of 12 to 20 meters. Placer gold has been detected for about 2 kilometers below the main workings. The placer deposit begins just below the contact between quartz monzonite and sheared hornfels, which may be a mineralized source for the placer minerals. The stream gradient is very steep and averages about 100 meters/kilometer at the head of Alder Gulch. ? Principle heavy minerals identified during mining activities include placer gold that exhibits a fineness of 930, abundant native bismuth and scheelite; minor hastingsite, ilmenite, magnetite, and zircon; trace amounts of monazite, and ilmenorutile; and up to 2.6 ppm PGE (Bundtzen, 1986). The mineralogical source of the PGE is unknown. Sulfide-scheelite-quartz float found in the placer cut contains up to 14.3 grams/tonne gold (Bundtzen, 1986).
  • Age = Quaternary, based on geomorphic character (in active stream basin).

Economic information

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic

Comments on exploration

  • Status = Active

Mining district

District name McGrath

Comments on the production information

  • Production Notes = Between 1930 and 1932, Carl Shutler mined in shallow hand mining cuts and produced 106.5 ounces (3.3 kg) gold and 20.2 ounces (0.6 kg) of byproduct silver Bundtzen, 1986). In 1981 and 1982, Peter Snow produced 16.5 ounces (503 grams) gold and 3.5 ounces (108 grams) of silver from a series of small test pits using a small tractor.

Comments on the workings information

  • Workings / Exploration = Surface exploration includes samples collected and processed by mine operator Peter Snow and samples reported by Bundtzen (1986). Sulfide-scheelite-quartz float found in the mine cut contain up to 14.3 grams/tonne gold.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A015043
USGS Alaska Resource Data File ARDF MG010

Bibliographic references

  • Deposit

    Bundtzen, T.K., 1986, Prospect examination of a gold-tungsten placer deposit in Alder Creek, Vinasale Mountain area, western Alaska: Alaska Division of Geological and Geophysical Surveys Public Data File Report 86-15, 10 pages.

  • Deposit

    Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Iliamna, Lake Clark, Lime Hills, and McGrath quadrangles, Alaska: U.S. Geological Survey Open-File Report 76-485, 101 p.

  • Deposit

    Cobb, E.H., 1973, Placer deposits of Alaska: U.S. Geological Survey Bulletin 1374, 213 p.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the McGrath quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-379, 1 sheet, 1:250,000 scale.

Comments on the references

  • Primary Reference = Bundtzen, 1986

General comments

Subject category Comment text
Deposit Model Name = Gold heavy mineral placer (Cox and Singer, 1986; model 39a).
Deposit Other Comments = Bundtzen (1986) collected a series of bulk concentrate samples from Peter Snow's 1982 operation, and concluded that up to 68 kilograms of scheelite could be recovered from one tonne of concentrate.

Reporter information

Type Date Name Affiliation Comment
Reporter 30-OCT-98 T.K. Bundtzen Pacific Rim Geological Consulting