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Jap

Past Producer in Alaska, United States with commodity Gold
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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 10003465
MRDS ID A106223
Record type Site
Current site name Jap

Geographic coordinates

Geographic coordinates: -149.32269, 61.78956 (WGS84)
Relative position On slope 2,500 ft northwest of headwaters of Upper Willow Creek. Accurate to with 3,000 ft. Locality 12 of Cobb (1972) and locality 10 of MacKevett and Holloway (1977).

Site location context

Political divisions (FIPS codes)

Matanuska-Susitna(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Anchorage D-7(quadrangle 1:63,360 scale)

Anchorage NW(quadrangle 1:100,000 scale)

Anchorage(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Lower Susitna River(hydrologic unit)

Susitna River(hydrologic accounting unit)

South Central Alaska(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary

Materials information

Materials Type of material
Gold Ore
Quartz Gangue

Alteration

  • (Local) Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954).

Mineral occurrence model information

Model code 273
USGS model code 36a
Deposit model name Low-sulfide Au-quartz vein
Mark3 model number 27

Nearby scientific data

(1) -149.32269, 61.78956
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = At least two quartz veins that range from a few inches to 18 inches in width and yield high assays of gold cut the Late Cretaceous Willow Creek Pluton. The veins may represent a faulted northward extension of the Gold Bullion vein (see Gold Bullion - ARDF number AN004) or may also represent the westward extension of either the Independence vein or Skyscraper vein (see Independence - ARDF number AN001) south of the Martin fault (Ray, 1954).? the Willow Creek Pluton is a zoned pluton: the outer part consists of hornblende quartz diorite and lesser hornblende tonalite; the core consists of hornblende-biotite granodiorite, and lesser hornblende-biotite quartz monzodiorite and biotite quartz monzonite. Wall-rock alteration within a few inches of the veins is intense, but seldom extends more than 10 to 12 inches beyond the quartz filling. Sericitization and carbonate alteration predominate, but there is some pyritization and in the outer parts of the alteration zone chloritization is present (Ray, 1954).
  • Age = Late Cretaceous or younger; vein cuts the Late Cretaceous Willow Creek Pluton.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Willow Creek

Comments on the production information

  • Production Notes = No attempt was made to mine ore carrying less than $100/ton (about 4.85 oz/ton) in gold (Brooks, 1925). Total production, if any, is unknown.

Comments on the workings information

  • Workings / Exploration = Development included four adits 400, 100, 25, and 30 ft in length (Brooks, 1925). A small mill was installed in 1915 (Capps, 1916). The prospect tunnels are now inaccessible, but the vein has been explored by diamond drilling (Ray, 1954).

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Brooks, 1925

General comments

Subject category Comment text
Deposit Model Name = Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)

Reporter information

Type Date Name Affiliation Comment
Reporter 30-JUL-1998 D.P. Bickerstaff U.S. Geological Survey
Reporter 30-JUL-1998 S.W. Huss U.S. Geological Survey

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.