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Pyrrhotite

Prospect in Alaska, United States with commodities Cobalt, Copper, Iron, Nickel, Zinc
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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 10307864
Record type Site
Current site name Pyrrhotite

Geographic coordinates

Geographic coordinates: -153.78083, 62.28648 (WGS84)
Relative position The Pyrrhotite prospect is located on a steep, precipitous southerly flank of Peak 6,920 at the head of Sheep Creek. It is about 1.5 kilometers southwest of the Badnews Prospect (MG061)) at an elevation of 5,750 feet (1,753 m) in the NW1/4 sec. 5, T. 25 N., R. 24 W., of the Seward Meridian. The reporter investigated the site 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 B-2(quadrangle 1:63,360 scale)

McGrath SE(quadrangle 1:100,000 scale)

McGrath(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Kuskokwim River(hydrologic accounting unit)

Southwest(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Cook Inlet Region, Incorporated(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
Cobalt Critical Primary
Copper Primary
Iron Primary
Nickel Critical Primary
Zinc Critical Secondary

Materials information

Materials Type of material
Pyrite Ore
Pyrrhotite Ore
Calcite Gangue

Alteration

  • (Local) None.

Mineral occurrence model information

Model code 72
USGS model code 19a
Deposit model name Polymetallic replacement
Mark3 model number 47

Nearby scientific data

(1) Qs
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Pyrrhotite occurrence consists of several semi-massive to massive pods of pyrrhotite and minor pyrite enclosed in banded hornfels and marble adjacent to a small stock of highly altered granodiorite porphyry. The host rocks are thermally altered marble and clastic sediments of the mid-Silurian Terra Cotta Mountains Sandstone, a unit of the Dillinger subterrane (Bundtzen and others, 1997). . Pyrrhotite occurs as disseminated grains in veinlets up to 8 centimeters thick, as semimassive to massive sulfide pods up to 30 centimeters thick, and as clots and crystals up to three centimeters across. Grab samples of pyrrhotite-rich sulfide mineralization collected during investigations by Anaconda Minerals Company contained up to 0.44 percent nickel and 460 ppm cobalt (Brewer and others, 1992). Selected samples reported by Foley (1987) contain up to 180 ppm nickel, 180 ppm copper, and 180 ppm zinc. Massive pyrrhotite-bearing samples contained 58.00 percent iron.

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Inactive

Mining district

District name McGrath

Comments on the workings information

  • Workings / Exploration = The Pyrrhotite occurrence was noted by the reporter during mapping conducted in 1981 (Bundtzen, Kline, and Clough, 1982). Grab samples of pyrrhotite-rich sulfide mineralization collected by Anaconda Minerals Company contained up to 0.44 percent nickel and 460 ppm cobalt (Brewer and others, 1992). Selected samples reported by Foley (1987) contain to 180 ppm nickel, 180 ppm copper, and 180 ppm zinc. Massive pyrrhotite-bearing samples contained up to 58.00 percent iron.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Foley, 1987

General comments

Subject category Comment text
Deposit Model Name = Polymetallic replacement (?) (Cox and Singer, 1986; model 19a).
Deposit Other Comments = See Post Lake Prospect (MG069).

Reporter information

Type Date Name Affiliation Comment
Reporter 08-DEC-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.