Rocky Cummins

Prospect in Alaska, United States with commodities Silver, Gold, Bismuth, Antimony, Tin, Tungsten
Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Mineral occurrence model information
  8. Host and associated rocks
  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 10096771
MRDS ID A011557
Record type Site
Current site name Rocky Cummins
Alternate or previous names Cummins

Geographic coordinates

Geographic coordinates: -150.82892, 62.71761 (WGS84)
Relative position Clark and Hawley (1968) locate this prospect 4.5 miles southeast of Mt. Goldie at about 2900 feet elevation in the southwest quarter of Section 5, T. 30 N., R. 8 W., of the Seward Meridian within Denali National Park and Preserve. Also shown as locality 45 in Reed and others (1978) and locality 15 in Hawley and Clark (1973) in a southeasterly flowing tributary about three miles upstream on the west side of the Tokositna Glacier.

Site location context

Political divisions (FIPS codes)

Matanuska-Susitna(Borough)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Talkeetna C-2(quadrangle 1:63,360 scale)

Talkeetna NE(quadrangle 1:100,000 scale)

Talkeetna(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Chulitna River(hydrologic unit)

Susitna River(hydrologic accounting unit)

South Central Alaska(hydrologic subregion)

Alaska(hydrologic region)

Federal lands

Denali National Park(National Park)

National Park NPS(Type of land area)

NPS(Federal land areas administered by NPS)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Bismuth Critical Secondary
Antimony Critical Secondary
Tin Critical Secondary
Tungsten Critical Secondary

Comments on the commodity information

  • Ore Material = unknown silver-bearing mineral
  • Ore Material = unknown silver-bearing mineral

Materials information

Materials Type of material
Arsenopyrite Ore
Gold Ore
Pyrite Ore
Quartz Gangue

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 Host
    Rock type

Nearby scientific data

(1) -150.82892, 62.71761

Economic information

Comments on the geologic information

  • Geologic Description = Mesozoic graywacke and argillite (KJs, Reed and Nelson, 1980) host steeply dipping, N75W striking, quartz veins in a 30 -foot-wide zone. Minor sporadic gold values occur within this zone, along with traces of silver, bismuth and tin (Cobb and Reed, 1980). Quartz is milky white, locally vuggy with minor pyrite, arsenopyrite, an unidentified gray-brown metallic mineral, white mica and free gold (Clark and Hawley, 1968; Hawley and Clark, 1973). The veins may be related to the Tertiary Kahiltna pluton (Tmk) mapped by Reed and Nelson (1980) to the northwest.? Clark and Hawley (1968) report samples containing 0.02 to 1.4 ppm Au, up to 20 ppm Ag, with anomalous As, Bi, Sn and W. ? Stream sediment samples from four streams in the area between the Tokositna and Kahiltna Glaciers indicate the area is auriferous and could host other prospects (Clark and Hawley, 1968). See TL015.
  • Age = Tertiary; mineralization is interpreted to be linked to the Kahiltna pluton (Tmk), part of the McKinley Sequence, that has been determined to range from 52.3 to 56.2 m.y. in age by K/Ar method (Reed and Lanphere, 1972; Reed and Nelson, 1980).
  • Age = Chron age is for McKinley Sequence.

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Mining district

District name Yentna

Comments on the workings information

  • Workings / Exploration = Some small prospect pits and reconnaissance mapping, stream silt and rock sampling (Clark and Hawley, 1968) are all that have been done here. Clark and Hawley (1968) report samples containing 0.02 to 1.4 ppm Au, up to 20 ppm Ag, with anomalous As, Bi, Sn and W.

Reference information

Bibliographic references

  • Deposit

    Clark, A.L., and Hawley, C.C., 1968, Reconnaissance geology, mineral occurrences, and geochemical anomalies of the Yentna district, Alaska: U.S. Geological Survey Open-File Report 68-35, 64 p.

  • Deposit

    Hawley, C.C., and Clark, A.L., 1973, Geology and mineral deposits of the upper Chulitna district, Alaska: U.S. Geological Survey Professional Paper 758-A, p. 1-10, 2 sheets, scale 1:250,000 and 1:500,000.

  • Deposit

    Reed, B.L., Nelson, S.W., Curtin, G.C., and Singer, D.A., 1978, Mineral resources map of the Talkeetna Quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-870-D, 1 sheet, scale 1:250,000.

  • Deposit

    Cobb, E.H., and Reed, B.L., 1980, Summaries of data and lists of reference to metallic and selected nonmetallic mineral deposits in the Talkeetna quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-884, 106 p.

  • Deposit

    Reed, B.L., and Nelson, S.W., 1980, Geologic map of the Talkeetna quadrangle: U.S. Geological Survey Miscellaneous Investigations Map I-1174, scale 1:250,000.

  • Deposit

    Clark, A.L., and Cobb, E.H., 1972, Metallic mineral resources map of the Talkeetna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-369, 1 sheet, scale 1:250,000.

  • Deposit

    MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.

Comments on the references

  • Primary Reference = Clark and Hawley, 1968

General comments

Subject category Comment text
Deposit Model Name = Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a).
Deposit Other Comments = This prospect lies within Denali National Park and Preserve.

Reporter information

Type Date Name Affiliation Comment
Reporter 10-AUG-1998 Madelyn A. Millholland Millholland & Associates

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.