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Badnews

Prospect in Alaska, United States with commodities Silver, Gold, Copper, Zinc, Cadmium, Cobalt, Lead
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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 10307863
Record type Site
Current site name Badnews

Geographic coordinates

Geographic coordinates: -153.76883, 62.29648 (WGS84)
Relative position The Badnews Prospect is located on a steep and precipitous, north-facing slope of Peak 6,920, at an elevation of 5,700 feet (1,738 m) in the SW1/4 sec. 32, T. 26 N., R. 24 W., of the Seward Meridian. The location is from Foley (1987).

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
Silver Primary
Gold Primary
Copper Primary
Zinc Critical Primary
Cadmium Secondary
Cobalt Critical Secondary
Lead Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Pyrite Ore
Pyrrhotite Ore
Sphalerite Ore
Calcite Gangue
Epidote Gangue
Garnet Gangue
Quartz Gangue

Alteration

  • (Local) Strong secondary biotite (potassic) alteration in skarn.

Mineral occurrence model information

Model code 60
USGS model code 18c
Deposit model name Skarn Zn-Pb
Mark3 model number 22

Nearby scientific data

(1) -153.76883, 62.29648
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Badnews polymetallic prospect is a Cu-Pb-Zn-Ag-Au (Co-Pb) skarn deposit in tightly folded limestone, siltstone, and argillite of the mid-Silurian Terra Cotta Mountains Sandstone, a unit of the Dillinger subterrane (Bundtzen, Harris, and Gilbert, 1997). The limestone layers have been preferentially replaced by skarn minerals and locally sulfides; clastic rocks have been transformed into purple-green hornfels. Central to the prospect area is a granodiorite porphyry stock with apophyses and numerous dikes intruding a large aureole of hornfelsed sedimentary rocks (Bundtzen, Harris, and Gilbert, 1997). Several east-west trending, high-angle, granodiorite dikes cut the limestone; the dikes are apparently pathways for hydrothermal-skarn mineralization. A post skarn breccia occurs at the contact of one granodiorite dike. . Principle sulfide minerals include; chalcopyrite, pyrrhotite, sphalerite, and a trace of galena. Pyrrhotite is the dominant sulfide in practically all mineralized skarn zones. Skarn gangue includes abundant recrystallized calcite and red garnet, with minor epidote and quartz. Massive sulfide pods and mantos ranging up to 10 meters thick can be traced laterally for several hundred meters (Brewer and others, 1992). Individual sulfide zones reach a maximum thickness of 0.7 meters within skarn zones up to 2 meters wide. Sphalerite is most abundant in epidote-garnet-rich rock whereas chalcopyrite and pyrrhotite are most abundant in lighter calcite-garnet rock (Foley, 1987). In sulfide skarns where chalcopyrite and sphalerite dominate, 23 grab samples averaged 3.7 percent zinc and 0.4 percent copper (Brewer and others, 1992). Selected samples from zinc-rich areas also contain up to 1,740 ppm cadmium. Overall gold values are more anomalous in the Badnews skarn prospect than in any other area of the Farewell Mineral Belt, with assays of up to 11.2 grams/tonne gold and 143.1 grams/tonne silver noted (Brewer and others, 1992). An average gold value of 490 ppb gold was obtained from numerous other sulfide-bearing grab samples at the prospect. Two grab samples of sulfide-bearing skarn collected by Foley (1987) contained maximum values of 9.20 percent zinc, 93 ppm lead, 0.44 percent copper, 290 ppm cobalt, and 16.6 grams/tonne silver.

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 Badnews polymetallic prospect was named by Roger Burleigh during mineral investigations conducted in 1979 by Placid Oil Company. Only surface sampling has taken place at the site, mainly by Anaconda Minerals and the U.S. Bureau of Mines. Where sphalerite and chalcopyrite dominate, 23 grab samples average 3.7 percent zinc and 0.4 percent copper (Brewer and others, 1992). Overall gold values are more anomalous in the Badnews skarn prospect than in any other area of the Farewell mineral belt; with assays of up to 11.2 grams/tonne gold and 143.1 grams/tonne silver noted (Brewer and others, 1992). Two samples of sulfide-bearing skarn collected by Foley (1987) contained up to 9.20 percent zinc, 93 ppm lead, 0.44 percent copper, 290 ppm cobalt, and 16.6 grams/tonne silver.

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Foley, 1987

General comments

Subject category Comment text
Deposit Model Name = Low temperature lead-zinc skarn (Cox and Singer, 1986; model 18c).
Deposit Other Comments = Similar to Tin Creek-Midway (MG043), and Rat Fork-Headwall (MG059) prospects. The Badnews skarn prospect contains more gold than any other prospect or occurrence in the Farewell Mineral Belt.

Reporter information

Type Date Name Affiliation Comment
Reporter 07-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.