Shungnak River Mine, Shungnak District, Northwest Arctic Borough, Alaska, USA

Semiprecious quality nephrite (jade) boulders were found during placer mining and in the stream gravels of the Shungnak River (Bernice Sheldon, oral communication, 1991).
Location: The Shungnak River placer mine is about a mile below the mouth of the river canyon. The deposit probably extends northward into the Ambler river quadrangle. The map site is in the E1/2 section 34, T. 19 N., R. 7 E., of the Kateel River Meridian. Location is accurate to within a radius of 1,000 feet.
Geology: Placer gold was first mined from the Shungnak River in 1898. It was mined continuously through 1913, and intermittently on a small scale into the 1950's. Bedrock is predominately lower to mid-Paleozoic black shale and schist; some Jurassic-Cretaceous serpentinite also is in the immediate area. The stream gravels are unfrozen. Typically the top 2 feet of gravel was removed as overburden. The gold is mostly on bedrock, particularly in areas of black shale. The gold is reddish with a dull luster, shaped like flattened shot, and usually in small pieces. Assay value was $16.70 per ounce in 1931. The recovery during 1931 was on the order of $0.90 per cubic yard. Pay streaks were irregular and unpredictable. Magnetite is the most abundant mineral in the concentrates. Occasionally small nuggets of copper and silver were found in the sluice box (Smith, 1913). Some boulders of semiprecious nephrite (jade) were recovered during mining.
Workings: Gold was first mined from the Shungnak River in 1898. It was mined continuously through 1913, and intermittently on a small scale into the 1950's.
Age: Quaternary.
Production: Smith (1913) states that a liberal estimate of total production to 1912 would be less than $50,000.

Commodities (Major) - Au; (Minor) - Ag, Cu, nephrite
Development Status: Yes; small
Deposit Model: Placer Au-PGE (Cox and Singer, 1986; model 39a).

References:
Cobb, E.H., 1973, Placer deposits of Alaska: U.S. Geological Survey Bulletin 1374, 213 p. Cobb, E.H., 1977, Placer deposit map of central Alaska: U.S. Geological Survey Open-File Report 77-168-B, 64 p., 1 map, scale 1:1,000,000. Mayfield, C.F., and Grybeck, D., 1978, Mineral occurrences and resource map of the Ambler River quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-120-I, 1 sheet, scale 1:250,000. Reed, I.M., 1931, Report on the placer deposits of the upper Kobuk goldfields: Alaska Territorial Department of Mines Miscellaneous Report 37-1, 57 p. Smith. P.S., 1913, The Noatak-Kobuk region, Alaska: U.S. Geological Survey Bulletin 536, 60 p.