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  3. Mineral Resource Data System (MRDS)

Yakobi Island

Past Producer in Alaska, United States with commodities Gold, Copper
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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. Host and associated rocks
  10. Nearby scientific data
  11. Economic information about the deposit and operations
  12. Mining district
  13. Links to other databases
  14. Bibliographic references
  15. General comments
  16. Reporter information

Geologic information

Identification information

Deposit ID 10002291
MRDS ID A013195
Record type Site
Current site name Yakobi Island
Alternate or previous names Miner Island

Geographic coordinates

Geographic coordinates: -136.34511, 58.01165 (WGS84)
Relative position The mine is accurately located (to within 0.1 mile) on the shore line of Yakobi island, northwest of Miner Island. It is on the point west of the junction of Lisianski Strait with Lisianski Inlet (west ). The site is location number 64 of Cobb (1972).

Site location context

Political divisions (FIPS codes)

Hoonah-Angoon(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Mount Fairweather A-2(quadrangle 1:63,360 scale)

Juneau SW(quadrangle 1:100,000 scale)

Mount Fairweather(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Central Southeast Alaska(hydrologic accounting unit)

Southeast Alaska(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Tongass National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Copper Secondary

Comments on the commodity information

  • Gangue = Clay (gouge)
  • Ore Material = Gold (native)

Materials information

Materials Type of material
Chalcopyrite Ore
Gold Ore
Quartz Gangue

Alteration

  • (Local) Clay gouge developed along shear zone.

Mineral occurrence model information

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

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock
    Stratigraphic age (youngest) Late Cretaceous
  • Host or associated Associated
    Rock type Plutonic Rock > Ultramafic Intrusive Rock > Hornblendite
  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock

Nearby scientific data

(1) Jise
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Yakobi Island gold-quartz vein is within an intrusion of quartz diorite, of Cretaceous age, which forms a major granitic batholith on Chichagof, Baranof, and Yakobi Islands (Loney and others, 1975). A coarse-grained hornblendite occurs within a few feet of the vein deposit. ? the mineralized quartz vein is from 1to 3 feet wide, dips steeply, and strikes northwest. The quartz occurs along a shear zone, associated with clay gouge, in a dark colored phase of the quartz diorite. Locally, the vein contains small amounts of chalcopyrite and native gold. The vein was developed by a short adit; the quartz pinched out in the adit, but was picked up on strike on the surface above the workings, indicating that quartz masses along the shear zone are lenticular (Overbeck, 1919).
  • Age = Cretaceous or younger.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic

Mining district

District name Chichagof

Comments on the production information

  • Production Notes = About 55 ounces of gold were produced before 1917.

Comments on the workings information

  • Workings / Exploration = A 35-foot-long adit was driven about 1887 on the shear zone, just above tide level. Four claims were active in 1917.

Reference information

Bibliographic references

  • Deposit

    Overbeck, R.M., 1919, Geology and mineral resources of the west coast of Chichagof Island: U.S. Geological Survey Bulletin 692, p. 91-136.

  • Deposit

    Rossman, Darwin, 1959, Geology and ore deposits of the northwestern part of Chichagof Island, Alaska: U.S. Geological Survey Bulletin 1058-E, p. 139-216.

  • Deposit

    Loney, R.A., Brew, D.A., Muffler, L.J. B., and Pomeroy, J.S., 1975, Reconnaissance geology of Chichagof, Baranof, and Kruzof Islands, southeastern Alaska: U.S. Geological Survey Professional Paper 792, 105 p.

  • Deposit

    Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Mt. Fairweather and Skagway quadrangles, Alaska: U.S. Geological Survey Open-File Report 78-316, 123 p.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Mount Fairweather quadrangle, AK: U.S. Geological Survey Miscellaneous Field Study Map MF-436, 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Overbeck, 1919

General comments

Subject category Comment text
Deposit Model Name = Low-sulfide gold-quartz vein (Cox and Singer, 1986; model 36a).
Deposit Other Comments = the site is in Rossman's hypothetical gold belt (plate 16, 1959). The site is in Tongass National Forest on land of unknown mining status.

Reporter information

Type Date Name Affiliation Comment
Reporter 14-APR-99 Hawley, C.C. Hawley Resource Group

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.