Kougarok River

Mine, Active

Alternative names

Washington Creek

Commodities and mineralogy

Main commodities Au
Other commodities Pb; Sn
Ore minerals cassiterite; galena; gold

Geographic location

Quadrangle map, 1:250,000-scale BN
Quadrangle map, 1:63,360-scale C-6
Latitude 65.735
Longitude -164.855
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. Washington Creek is the western headwater tributary of Kougarok River. This location includes the upper 2 miles of the Kougarok River and the lower, almost 3 miles of Washington Creek; placer mining has been continuous over this length (Sainsbury and others, 1969). This is locality 23 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 on Kougarok River as early as 1900 when $50,000 worth of gold (about 3,000 ounces at $18 per ounce) was recovered (Brooks and others, 1901). Extensive dredging of the active floodplain has taken place throughout the upper two miles of the river and at least the lower parts of Washington Creek. Various dragline and dozer operations have also taken place along Washington Creek and bench placers have been locally productive along both drainages. Placer mining, including dredging, has continued locally in the upper Kougarok River area 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 gold is dark compared to that from tributaries (Collier and others, 1908). Placer concentrates have contained cassiterite, abundant pyrite, and magnetite (Knopf, 1908). The cassiterite that is reported from early operations may have been recovered from Washington Creek as the headwaters of Washington Creek drain Kougarok Mountain where lode tin deposits are present (Hudson, 1998). Sainsbury (1975, p. 69) reports that placer concentrate from Washington Creek contains cassiterite, pyrite, galena, and a silvery sulfide that predominately contains silver, tin and bismuth. Bits of cassiterite and base metal sulfides were also noted by Marsh and others (1972) in Washington Creek placer deposits. Bedrock is extensively mantled by tundra in the area but where exposed it is part of a Lower Paleozoic metasedimentary assemblage (Sainsbury and others, 1969; Till and others, 1986).
Geologic map unit (-164.857701840557, 65.7342765855929)
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 floodplains of the area are probably the result of at least two cycles of erosion and placer developement.

Production and reserves

Workings or exploration Open-cut placer workings, including extensive areas of dredging, are continuous along the upper 2 miles of Kougarok River and the lower almost 3 miles of Washington Creek.
Indication of production Yes; medium
Reserve estimates Placer mining claims cover much of the upper Kougarok River area, including the area south of Taylor (BN035). Placer mining has continued locally in this area and reserves probably remain, particularly between meanders on the active floodplain and on unmined benches.
Production notes Brooks (1901) reported initial production at the turn of the century of $50,000 (about 3,000 ounces at $18 per ounce); thisis 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 A010727

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