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Von Frank - South

Prospect in Alaska, United States with commodities Gold, Copper, Arsenic, Molybdenum
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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 10307785
Record type Site
Current site name Von Frank - South

Geographic coordinates

Geographic coordinates: -154.33797, 63.5275 (WGS84)
Relative position The Von Frank - South prospect is situated on a southerly spur of Von Frank mountain at an elevation of approximately 2,550 feet (777 m) in Section 1, T. 23 S., R. 23 E., of the Kateel River Meridian. The reporter visited the site in 1990.

Site location context

Political divisions (FIPS codes)

Yukon-Koyukuk(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Medfra C-3(quadrangle 1:63,360 scale)

Medfra N(quadrangle 1:100,000 scale)

Medfra C(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Takotna 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
Gold Primary
Copper Primary
Arsenic Critical Secondary
Molybdenum Secondary

Comments on the commodity information

  • Gangue = carbonate

Materials information

Materials Type of material
Arsenopyrite Ore
Bournonite Ore
Chalcopyrite Ore
Molybdenite Ore
Pyrite Ore
Sphalerite Ore
Stibnite Ore
Quartz Gangue

Alteration

  • (Local) Quartz+sericite+ankerite in diorite intrusion.

Mineral occurrence model information

Model code 78
USGS model code 20c
Deposit model name Porphyry Cu-Au
Mark3 model number 34

Nearby scientific data

(1) -154.33797, 63.5275
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The Von Frank - South prospect is a chalcopyrite-pyrite-(moybdenite) quartz stockwork in a 69 Ma diorite stock, a cupola of the larger Von Frank Mountain monzonitic pluton (Patton and others, 1980; Moll and others, 1981; DiMarchi and others, 1994; Bundtzen and Miller, 1997). Much of the stockwork occurs in joint-fractures with regular N 55 E, 80 SE, and N 45 W, 75 SW orientations. Mineralized veinlets ranged from 1 inch to 6 inches (2.5 cm to 15 cm) thick and total about 15 per every 4 feet (1.2 m). About 90 percent of the stockwork is in plutonic rocks; the remaining 10 percent occurs in hornfels. Sulfides in stockwork from drill core include chalcopyrite, sphalerite, bournonite, stibnite, and pyrite. Bundtzen and Miller (1997) compare the Von Frank - South prospect with other Cu-Au Porphyry prospects in the Kuskokwim Mineral Belt of Southwest Alaska. Drill intercepts include 429 feet (131 m) of 0.13 ounces/ton (0.45 g/tonne) gold, and 135 feet (41 m) of 0.035 ounces/ton (1.2 grams/tonne) gold (Bundtzen and others, 1994). Up to 0.35 percent copper was also present in drill core. The best mineralization from surface samples yielded 0.559 ounces (19.1 grams/tonne) gold. Gold and copper have a correlation coefficient of 0.92 (DiMarchi and others, 1994).
  • Age = Late Cretaceous (69.0 Ma), based on biotite age in host diorite (Bundtzen and others, 1994).

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 = ASA Inc. discovered the Von Frank-South prospect in 1992. In 1993, ASA Inc., an Alaskan-based exploration firm, completed 2,000 feet (610 m) of reconnaissance diamond drilling, geologic mapping, and geochemical sampling. Drill intercepts include 429 feet (131 m) with an average grade of 0.013 ounces/ton (0.45 grams/tonne) gold, and 135 feet (41 m) of 0.035 ounces/ton (1.2 grams/ton) gold (Bundtzen and others, 1994). Up to 0.35 percent copper was also detected in drill core, but analytical results from mineralized sample widths were not available. The highest grade surface sample yielded 0.559 ounces/ton (19.1 grams/tonne) gold. Gold and copper have a correlation coefficient of 0.92, with much lower values of gold and other metals (DiMarchi and others, 1994).

Reference information

Bibliographic references

  • Deposit

    Patton, W.W., Jr., Moll, E.J., Dutro, J.T., Jr., Silberman, M.L., and Chapman, R.M., 1980, Preliminary geologic map of Medfra quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-811-A, 1 sheet, scale l:250,000.

  • Deposit

    DiMarchi, J.J., Weglarz, T.B., Adams, D.D., Huber, J., and West, A.W., 1994, Annual Report for 1993--Doyon Option Lands, Volume 1: ASA Inc. Report, 187 p. (Report held by Doyon Ltd., Fairbanks, Alaska.)

  • Deposit

    Bundtzen, T.K., and Miller, M.L., 1997, Precious metals associated with Late Cretaceous-early Tertiary igneous rocks of southwestern Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Economic Geology Monograph #9, Mineral Deposits of Alaska, p. 242-286.

  • Deposit

    Bundtzen, T.K., Swainbank, R.C., Clough, A.H., Henning, M.W., and Hansen, E.W., 1994, Alaska's mineral industry, 1993: Alaska Division of Geological and Geophysical Surveys Special Report 48, 84 p.

Comments on the references

  • Primary Reference = DiMarchi and others, 1994

General comments

Subject category Comment text
Deposit Model Name = Porphyry Cu-Au (Cox and Singer, 1986; model no. 20c)
Deposit Other Comments = See Von Frank - North (MD035), Montana Saddle (MD0180), and Neirod - East (MD020) prospects. The Von Frank - South prospect is on land selected or owned by Doyon Ltd. For additional information, contact Doyon Ltd. at 210 1st Ave., Fairbanks, Alaska, 99701.

Reporter information

Type Date Name Affiliation Comment
Reporter 03-JUN-98 Bundtzen, T.K. 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

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