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Alder Gulch

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

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

McGrath C-6(quadrangle 1:63,360 scale)

McGrath NW(quadrangle 1:100,000 scale)

McGrath(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Stony River(hydrologic unit)

Upper Kuskokwim River(hydrologic accounting unit)

Southwest(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Doyon, Limited(ANCSA Region)

ANCSA Region NTVPIC(Type of land area)

NTVPIC(Federal land areas administered by NTVPIC)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Bismuth Critical Secondary
PGE Critical Secondary
Antimony Critical Secondary
Tungsten Critical 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
Deposit model name Placer Au-PGE
Mark3 model number 54

Nearby scientific data

(1) -155.71291, 62.69556
ListMap

Economic information

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 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

Bibliographic references

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

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.