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Rossness & Larson

Past Producer in Alaska, United States with commodities Gold, Silver
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Geologic information

Identification information

Deposit ID 10000409
MRDS ID A010573
Record type Site
Current site name Rossness & Larson

Geographic coordinates

Geographic coordinates: -150.59253, 59.55949 (WGS84)
Relative position The Rossness and Larson mine is about 0.2 miles north of VAMB Mid on the north shore of the North Arm of Nuka Bay. The property consists of three short adits, numerous open cuts, and the ruins of the mill and camp. Two of the adits are near the beach at 30 and 50 feet above sea level; they are on each side of a small stream which drains into the cove. The third adit is at an elevation of 107 feet and about 250 feet northwest of the lower tunnels.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary
Silver Secondary

Materials information

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

Alteration

  • (Local) Borden and others (1991) report carbonization, sulfidization, sericitization, and silicification of the wall rock adjacent to the veins.

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 Sedimentary Rock > Clastic Sedimentary Rock > Siltstone
    Rock unit name Valdez Group
    Rock description Valdez Group;Valdez Group;

Nearby scientific data

(1) -150.59253, 59.55949
ListMap

Comments on the geologic information

  • Geologic Description = The host rock of the prospect is graywacke and thin slate interbeds of the Cretaceous Valdez Group (Richter, 1970). The quartz veins of this prospect consist of white crystalline quartz with various amounts of sulfides. Arsenopyrite is the dominate sulfide with minor amounts of pyrite. Gold occurs as free gold and associated with arsenopyrite. The veins at this prospect are lens shaped and generally follow the bedding which strikes N30W and dips 67S (Pilgrim, 1933). They range from less than one inch to over four feet in width. ? the southwest adit is 30 feet in length and follows a stockwork of parallel quartz veins. The veins range in width from 0.1 to 0.5 foot and strike N30W and dip 67S. A composite sample across four of these veins assayed 26 ppm gold (Richter, 1970). The northwest adit is caved and appears to have followed a single quartz-arsenopyrite vein that trends east-west and dips 80S. Richter (1970) sampled this vein and it contained 0.05 ppm gold. ?The upper adit at 110 foot elevation trends east-west and dips 80S. There are no assay results from this adit. ? North of the two adits near the beach, there is a pyritized, light colored dike swarm which trends N20W. A sample of this dike swarm contained 0.028 ounces of gold per ton (Pilgrim,1933).
  • Age = Tertiary; Boden and others (1991) report other veins in the district are about 55 m.y. old.

Economic information

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Homer

Comments on the workings information

  • Workings / Exploration = According to Pilgrim, (1933) the mine produced some gold during the 1931-33 period but it was inactive during Capps' 1936 visit (Capps, 1938, p. 32). Three adits totaling 170 feet in length and numerous surface cuts occur on the property. Composite samples by Richter (1970) of the southwest veins assayed 26 ppm gold. Samples by Pilgrim (1933) assayed between 0.08 and 0.064 ounces of gold and 0.40 ounces of silver per ton. A sample of the pyritic dike assayed 0.028 ounces of gold per ton (Pilgrim,1933).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A010573
USGS Alaska Resource Data File ARDF SV018

Bibliographic references

  • Deposit

    Pilgrim, E.R., 1933, Progress of lode mining in interior Alaska, 1932: Alaska Territorial Department of Mines Miscellaneous Report 194, 11 p.

  • Deposit

    Capps, S.R., 1938, Lode mining in the Nuka Bay district, in Smith, P.S., Mineral industry of Alaska in 1936: U.S. Geological Survey Bulletin 897-A, p. 25-32.

  • Deposit

    Berg, H.C., and Cobb, E.H., 1967, Metalliferous Lode Deposits of Alaska. U.S. Geological Survey Bulletin 1246, 254 p.

  • Deposit

    Cobb, E.H., 1972, Metallic minerals resources map of the Seldovia quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-397, 1 sheet, scale 1:250,000.

  • Deposit

    Borden, J.C., Goldfarb, R.J., Gent, C.A., Burruss, R.C., and Roushey, B.H., 1992 Geochemistry of lode-gold deposits, Nuka Bay district, southern Kenai Peninsula: Geologic studies in Alaska by the U.S. Geological Survey, 1991: U.S. Geological Survey Bulletin 2041, p. 13-21.

  • Deposit

    Cobb, E.H., 1979, Summary of references to mineral occurrences (other than minerals fuels and construction materials) in the Seldovia quadrangle, Alaska: U.S. Geological Survey Open-file Report 80-87, 47 p.

  • Deposit

    Richter, D.H., 1970, Geology and lode-gold deposits of the Nuka Bay area, Kenai Peninsula, Alaska: U.S. Geological Survey Professional Paper 625-B, p. Bl-B16.

  • 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 = Pilgrim, 1933

General comments

Subject category Comment text
Deposit Model Name = Low-sulfide, Au-quartz vein (Cox and Singer, 1986; model 36a)
Deposit Other Comments = This prospect is within the Kenai Fjords National Park; the park is closed to mineral entry.

Reporter information

Type Date Name Affiliation Comment
Reporter 17-FEB-99 Jeff A. Huber U.S. Geological Survey