West Coast Kodiak Island

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Cr; PGE
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale KR
Quadrangle map, 1:63,360-scale A-2
Latitude 57.14
Longitude -154.52
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site in the Karluk quadrangle represents an 18-mile stretch of beach which has been sporadically mined for placer gold. The beach extends southward to Cape Alitak in the Trinity Islands quadrangle (see Trinity Islands quadrangle, sites ARDF numbers TI001 and TI003) and northward to Red River on the Karluk B-2 quadrangle (Cobb, 1972, MF 459, locality 5; Cobb, 1973, Bulletin 1374, figure 11, locality 1; MacKevett and Holloway, 1977, locality 5).

Geologic setting

Geologic description

Placer mining in this area was first reported by Becker (1897) at Portage and Ayakulik Rivers. Maddren (1919) reported that finely divided gold was present along the entire beach. Becker's examination indicated that the gold occurs with other heavy minerals in patches approximately 1 inch thick and extending over a few square yards. The gold was scaly and not easy to amalgamate. The patches were not consistent in thickness or richness and thus did not form pay streaks in the usual sense. These patchy concentrations of heavy minerals consisted mostly of magnetite with lesser amounts of chromite, gold, pyrite, and a little platinum. In some instances good concentrations of gold were found to lie on a layer of compact clay bedrock. No estimates of gold values within these patchy zones of heavy minerals has been reported. Maddren (1919) estimated the total value of production of all the west coast Kodiak Island beaches up to 1917 to be $50,000 to $150,000 (gold at $20.67 per ounce), and an annual production valued at $3,000 to $10,000. Cobb (1973) estimates total production at probably not greater than a few thousand ounces. The immediate source of the gold appears to be nearby bluffs of glacial gravels and tills which are constantly being eroded by wave action.
An analysis of placer PGE concentrate from the beach (Maddren, 1919) is as follows: 26.9 percent iridium-osmium, rhodium; 6.1 percent iridium from part of iridium-osmium; 0.1 percent rhodium from part of iridium-osmium; 55.3 percent platinum; 2.4 percent iridium; 6.4 percent iron; 0.3 percent gold; 0.7 percent rhodium; 0.1 percent palladium; 0.6 percent copper; 0.08 percent nickel; trace silver and zinc. This sample recalculated free of impurities and totaled to 100 percent is as follows: 64.8 percent platinum; 10.0 percent iridium; 24.2 percent iridium plus osmium; 0.9 percent rhodium; 0.1 percent palladium (Mertie, 1969).
Geologic map unit (-154.522312398495, 57.1392349479322)
Mineral deposit model Gold-PGE placer (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quaternary

Production and reserves

Workings or exploration Small-scale placer mining has been reported in this area from 1898 to at least 1952. Maddren (1919) reports that in some years up to 100 men were engaged in placer mining. In 1917 twelve men were mining and in 1950-51 two men were mining. Mining was done by rockers and portable sluice boxes. All equipment had to be removed from the beach during high tides.
Indication of production Yes; small

References

MRDS Number A012463; M045383

References

Reporters S.H. Pilcher (Anchorage)
Last report date 9/11/1998