Osborn Creek

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold

Geographic location

Quadrangle map, 1:250,000-scale NM
Quadrangle map, 1:63,360-scale C-1
Latitude 64.5573
Longitude -165.1253
Nearby scientific data Find additional scientific data near this location
Location and accuracy This alluvial placer gold mine is on Osborn Creek, an east tributary to Nome River. More than 3.2 miles of Osborn Creek, between elevations of 75 and 150 feet, have been placer mined. This location is the approximate midpoint of the placer workings, at the south edge of the SW1/4 section 5, T. 11 S., R. 32 W., Kateel River Meridian. It is locality 120 of Cobb (1972 [MF 463], 1978 [OFR 78-93]).

Geologic setting

Geologic description

Placer gold was discovered on Osborn Creek in 1900. Except in an area just above St. Michaels Creek (NM277), Osborn Creek placer deposits mostly have gravel walls and pay streaks are floored by clay-rich false bedrock. Gravel was composed mostly of schist, marble, and quartz. Boulders of greenstone and granite (orthogneiss?) are abundant. Granite boulders believed by Collier to come from the Kigluaik Mountains were found as high as 800 feet on the 1,000-foot-tall mountain south of Willow Creek (Collier and others, 1908, p. 171).
Shallow placer deposits were mined for about 5 miles above the mouth of the Osborn Creek. Gravels probably contained about 2.50 to 4.50 dollars in gold (gold at 20.67 dollars per ounce; Collier and others, 1908, p. 171). Gravels were about 5 to 6 feet thick above a false bedrock in a pay section 100 feet wide. Gold was mostly coarse and well rounded, although some pieces were angular. A copper-bearing lode, reported to contain as much as 2 ounces of gold per ton (Smith, 1908), occurs above Osborn Creek (NM278), but much of the placer gold is probably reworked from coastal plain deposits.
Small-scale mining began about 1903 (Collier and others, 1908, p. 171-172) and was almost continuous up to WW II. Dredging was nearly continuous in two periods, from 1913 to 1924 and from 1928 to 1940 (Cobb, 1978 [OFR 78-93]). Larger scale mining developed by about 1911 with dredging and hydraulic mining (Smith, 1912; Chapin, 1914; Eakin, 1915 [B 622-I. p. 360-373]). The early period of dredging lasted until about 1924 (Smith, 1926). In 1928 another dredge was moved in from the Solomon River (Smith, 1930 [B 813]), and dredge mining occurred in most years at least through 1940 (Smith, 1942).
Bedrock in lower Osborn Creek is marble and schist, probably of early Paleozoic protolith age (Hummel, 1962 [MF 247]; Till and Dumoulin, 1994; Bundtzen and others, 1994).
Geologic map unit (-165.127908819048, 64.5565407719761)
Mineral deposit model Alluvial placer Au (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration Extensive placer tailings on Osborn Creek start about 0.2 mile downstream of the mouth of St. Michaels Creek (NM277) and continue upstream for about 3.2 miles. Most of these tailings are probably the result of dredge operations that were almost continuous between 1911 and 1940. Gold was discovered in the creek in 1900, and small-scale mining began by about 1903.
Indication of production Yes; medium
Production notes Although production data are not available, the continuity and extent of mining operations suggest that Osborn Creek was one of the more productive creeks in the Nome area.

References

MRDS Number A012940

References

Till, A.B., and Dumoulin, J.A, 1994, Geology of Seward Peninsula and St. Lawrence Island, in Plafker, G., and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, v. G-1, p. 141-152.
Reporters C.C. Hawley and Travis L. Hudson
Last report date 7/10/2000