Kougarok River

Mine, Active?

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Pb; Sn
Ore minerals cassiterite; galena; gold
Gangue minerals magnetite; pyrite

Geographic location

Quadrangle map, 1:250,000-scale BN
Quadrangle map, 1:63,360-scale C-6
Latitude 65.685
Longitude -164.789
Nearby scientific data Find additional scientific data near this location
Location and accuracy Kougarok River is the largest and most important drainage in the Kougarok mining district. It drains south from its headwaters in Washington Creek (BN041) and Macklin Creek (BN045) in the northern part of the Bendeleben C-6 quadrangle; it is at least locally gold-bearing over a length of 18 miles in this quadrangle. The part of the Kougarok River included in this locality is the mile upstream and the 7 to 8 miles downstream from the mouth of Taylor Creek. Taylor Creek is a major east tributary to Kougarok River. The mouth of Taylor Creek is 1,000 feet north of the termination of the Nome-Taylor road at Taylor. This part of the Kougarok River includes localities 24 and 25 of Cobb (1972; MF 417; 1975; OFR 75-429).

Geologic setting

Geologic description

Kougarok River is the largest and most important drainage in the Kougarok mining district. Placer mining started here as early as 1900 when $50,000 worth of gold (about 3,000 ounces at $18 per ounce) were recovered (Brooks and others, 1901). Extensive dredging of the active floodplain has taken place from a mile upstream to 7-8 miles downstream from the mouth of Taylor Creek (Sainsbury and others, 1969). Placer mining, including dredging, has continued locally to the present. Most of the more than 240,000 ounces of known production from the Kougarok district (Hudson and DeYoung, 1977) is from the upper part of Kougarok River. The recovered gold is dark compared to that from tributaries (Collier and others, 1908). Placer concentrates contain cassiterite, abundant pyrite, and magnetite (Knopf, 1908). A gray, sulfide-rich dredge concentrate contained 2,000 ppm Ag, 7,000 ppm Bi, and greater than 10 % Pb (Sainsbury and others, 1969, p. 39). Bedrock in the upper Kougarok River drainage is dominately Lower Paleozoic metasedimentary rocks (Sainsbury and others, 1969; Till and others, 1986). Placer deposits on the active floodplain are the result of two or more cycles of erosion and placer development in the area.
Geologic map unit (-164.79169675727, 65.6842756309524)
Mineral deposit model Placer Au-PGE (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a
Age of mineralization Quaternary; placer deposits on the active floodplain are the result of two or more cycles of erosion and placer development in the area.

Production and reserves

Workings or exploration The entire length of this segment of the Kougarok River has been extensively placer mined for gold. Sainsbury and others (1969) show where many of these mine workings are located but additional mine tailings are also shown on the USGS 1:63,360 topographic map of the area (Bendeleben C-6 quadrangle). Most of these placer mine workings are the result of dredge operations.
Indication of production Yes; medium
Production notes Brooks (1901) reports initial production at the turn of the century to be $50,000 (about 3,000 ounces at $18 per ounce); this is an indication of the richness of the upper Kougarok River area. Most of the more than 240,000 ounces of known production from the Kougarok district (Hudson and DeYoung, 1978) is from the upper part of Kougarok River.

References

MRDS Number A012697

References

Brooks, A.H., Richardson, G.B., Collier, A.J., and W.C. Mendenhall, 1901, A reconnaissance in the Cape Nome and adjacent gold fields of Seward Peninsula, Alaska, in 1900: U.S. Geological Survey Special Publication, p. 1-185, maps.
Reporters Travis L. Hudson (Applied Geology)
Last report date 3/15/1999