Kugruk River

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale BN
Quadrangle map, 1:63,360-scale D-1
Latitude 65.873
Longitude -162.451
Nearby scientific data Find additional scientific data near this location
Location and accuracy Kugruk River is a major north-flowing drainage in the northeast Bendeleben quadrangle. The mouth of Kugruk River is east of Deering on Kotzebue Sound. This mine is approximately located as on Kugruk River, 1 to 3 miles upstream of Chicago Creek, (BN068), an east tributary. This is locality 63 of Cobb (1972; MF 417; 1975; OFR 75-429).

Geologic setting

Geologic description

At this location, Kugruk River is a meandering stream in a 3,000 to 4,000 foot-wide floodplain. The elevation of the floodplain is less than 100 feet but some river terraces are present locally. A 30-foot high bench just above the mouth of Chicago Creek is reported to be auriferous (Roehm, 1941, p. 111). Placer mining for gold began as early as 1903 and initially included drift operations. Mining was variably located to be 1 to 3 miles upstream of Chicago Creek (BN068), an east tributary. Some dredging took place and an abandoned dredge was reported to be present by Cobb (1975). Between 1903 and 1905, gold production worth $150,000 (over 8,000 ounces) was reported from a crescent-shaped pay streak on Discovery claim (Henshaw, 1909). The gold was finer at the ends of the pay streak than in the middle. The depth to bedrock on Discovery claim was 12 to 14 feet including overburden. Henshaw (1909) describes a section 0.75 mile from Kugruk River near Discovery claim that included two gravel intervals. This section (from top down) was: 25 feet of clear ice, 60 feet of muck, 8 feet of reddish gravel, 3 feet of muck, and 10 feet of blueish gravel on schist bedrock. One mile above Chicago Creek, gravels were 8 to 10 feet thick on schist and marble bedrock; overburden was 5 to 7 feet thick (Henshaw, 1910). Bedrock in the area is mostly covered by tundra but it is probably part of a Lower Paleozoic metasedimentary assemblage (Till and others, 1986). Tertiary coal-bearing sediments are locally exposed along Kugruk River upstream from Chicago Creek.
Geologic map unit (-162.453693476122, 65.8723157219648)
Mineral deposit model Placer Au-PGE (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a
Age of mineralization Quaternary; two or more cycles of placer deposit development are indicated. The low elevation of the Kugruk River floodplain here indicates that Quaternary sea level fluctuations may have influenced the character of the placer deposits.

Production and reserves

Workings or exploration Both drift mining and dredging have take place here.
Indication of production Yes; small
Production notes Between 1903 and 1905, gold production worth $150,000 (over 8,000 ounces) was reported (Henshaw, 1909). This production was probably from drift mining.