Salmon River

The Salmon River is a gold mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Salmon River

Commodity

Primary: Gold
Secondary: Mercury
Secondary: Chromium
Secondary: Diamond

Location

State: Alaska
District: Goodnews Bay

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Producer
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Model Name: Placer PGE-Au

Orebody

Not available

Structure

Not available

Alterations

Not available

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Chromite
Ore: Cinnabar
Ore: Diamond
Ore: Gold
Ore: Ilmenite
Ore: Magnetite
Ore: Mercury
Ore: Sperrylite
Ore: Tetraferroplatinum

Comments

Comment (Production): Production Notes = A large part of the 650,000 ounces of PGM and 15,600 ounces of Au produced from the Salmon River area was recovered from this placer.

Comment (Reference): Primary Reference = Mertie, 1976

Comment (Workings): Workings / Exploration = The Salmon River valley paystreak was worked by dredge starting in 1937, and several parallel cuts totaling approximately 15 to 20 miles of workings up to 60 feet deep have been made. Considerable exploration drilling was completed to delineate the paystreak.

Comment (Geology): Geologic Description = This placer mine is located in the present valley of Salmon River. Dredge mining took place from the mouth of Boulder Creek (HG026), a west tributary, south about five miles to within 11/4 mile of the mouth of the river. The dredge tailings are commonly few hundred feet wide and confined to the active drainage. The paystreak was 300 to 450 feet wide, except near the mouth of Platinum Creek (HG014) where it was up to 600 feet wide (Mertie, 1969, p. 82). Overburden gravel, sand, and silt deposits vary from 30 to 80 feet thick and do not change systematically in thickness. The gravels are mostly well-rounded pebbles and cobbles up to 2 feet across interbedded with sand and silt; clay is not present. The pay is on an uneven, non-weathered bedrock surface that is locally incised up to 20 feet; in the overlying 2 feet of gravels; and in 2 feet of fractured bedrock. The tenor of the worked paystreak was 0.002 to 0.026 ounce of PGM per cubic yard (Fechner, 1988). PGM grains become smaller southward through the Salmon River valley paystreak, from 0.2 to less than 0.002 inch in diameter. Four samples of tailings from this mine contained up to 0.0037 ounce of PGM per cubic yard (Fechner, 1988, p. 190, 193). PGM grains from Salmon River valley and bench tailings contain 0.6 to 1.1 percent Rh, 0.4 to 0.7 percent Ru, 60.3 to 85.5 percent Pt, 3.8 to 25.6 percent Ir, 1.2 to 6.3 percent Os and 5.9 to 8.9 percent Fe (Fechner, 1988, p. 81). The PGM-bearing phases identified in these samples included iron-platinum alloy containing 8 to 30 percent Fe; iron-platinum alloy with minor osmiridium inclusions; and osmiridium, sperrylite, and tetraferroplatinum (Fechner, 1988, p. 81). Small amounts of cinnabar and traces of native mercury have been identified in dredge concentrates (Mertie, 1976, p. 38). Two small diamonds were identified in the nondissolved residue from 8 PGM granules (Mertie, 1976, p. 17). The Salmon River vally placer is continuous with the placer in Platinum Creek (HG014) and with the placers in some of its other west tributaries. The paystreak apparently ends or becomes uneconomic at the south end of the mine workings. The workings are all below surface elevations of 150 feet and their proximity to the coastline and low elevation suggests that Quaternary sea level changes could have influenced placer development.

Comment (Exploration): Status = Active

Comment (Reserve-Resource): Reserves = Inasmuch as the recovery efficiency of the dredge operations was about 60 percent, the mine tailings are a low-grade resource. Fechner (1988, p. 27) estimates that over 40 million cubic yards of tailings are present that could contain 0.0013 to 0.017 ounce of PGM per cubic yard.

Comment (Geology): Age = Quaternary.

Comment (Deposit): Model Name = Placer PGE-Au (Cox and Singer, 1986; model 39b)

References

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Hagemeister Island quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-362, 1 sheet, scale 1:250,000.

Reference (Deposit): Fechner, S.A., 1988, Bureau of Mines mineral investigation of the Goodnews Bay mining district, Alaska: U.S. Bureau of Mines Open-File Report 1-88, 230 p.

Reference (Deposit): Mertie, J.B., Jr., 1969, Economic geology of platinum minerals: U.S. Geological Survey Professional Paper 630, 120 p.

Reference (Deposit): Mertie, J.B., Jr., 1976, Platinum deposits in the Goodnews Bay district, Alaska: U.S. Geological Survey Professional Paper 938, 42 p.

Reference (Deposit): Cobb, E.H., 1980, Summaries of data and lists of references to metallic and selected nonmetallic mineral deposits in fifteen quadrangles in southwestern and west-central Alaska: U.S. Geological Survey Open-File Report 80-909, 103 p.

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