Birch Creek Mine, Ruby District, Yukon-Koyukuk Borough, Alaska, USA
This page is currently not sponsored. Click here to sponsor this page.
Geology: The bedrock under Birch Creek consists of granite near the head of the creek and black pyritic slate/shale further downstream (Mertie and Harrington, 1916). The creek contains both placer gold and cassiterite. Concentrates from stream placers and granite bedrock contained allanite, zircon, hematite, anatase, garnet, ilmenite, malachite, titanite (sphene), and traces of a radioactive mineral that may be uranothorite (White and Stevens, 1953). The mineralization may be related to the intrusive contact zone and veining(?) in pyritic shale (Eberlein and others, 1977). Birch Creek was first staked in 1914. Gold was found for more than 2 miles along lower Birch Creek and between Straight and Crooked Creeks. The gold was found on or near bedrock at depths of 70 to 90+ feet below the surface. Three mines operated between 1914-15 (Mertie and Harrington, 1916) and Green Mountain Mining and Exploration mined between 1993 and 1995 (Bundtzen and others, 1996). The gold from the granite area is fairly coarse and badly tarnished. Gravels from further downstream contain mostly pyrite from the underlying slate (Mertie and Harrington, 1916). The mean of three assays yielded 872 parts per thousand gold and 120 parts per thousand silver (Mertie, 1936).
Workings: Prospecting and mining were rendered difficult due to depth to paystreak and the presence of thawed ground above that depth in places. Mertie and Harrington (1916) reported that 'live water' was encountered in some shafts and drifts 80+ feet below ground surface. During 1914-1915, three underground mines were being worked (Mertie and Harrington, 1916). Green Mountain Mining and Exploration mined ground from 1993 to 1995 (Bundtzen and others, 1996).
Production: An unknown (probably small) quantity of placer gold was recovered from this creek.
Commodities (Major) - Au, Sn; (Minor) - Ag, Bi, Th, U
Development Status: Yes; small
Deposit Model: Placer Au (Cox and Singer, 1986; model 39a).
13 entries listed. 10 valid minerals.
The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.
Bundtzen, T.K., Swainbank, R.C., Clough, A.H., Henning, M.W., and Charlie, K.M., 1996, Alaska's mineral industry, 1995: Alaska Division of Geological and Geophysical Surveys Special Report 50, 72 p. Chapman, R.M., Coats, R.R., and Payne, T.G., 1963, Placer tin deposits in central Alaska: U.S. Geological Survey Open-File Report 239, 53 p. Cobb, E.H., 1972, Metallic mineral resources map of the Ruby quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-405, 1 sheet, scale 1:250,000. Cobb, E.H., and Chapman, R.M., 1981, Mineral occurrences (other than mineral fuels and construction materials) in the Kantishna River and Ruby quadrangles, Alaska: U.S. Geological Survey Open-File Report 81-170, 94 p. Eberlein, G.D., Chapman, R.M., Foster, H.L., and Gassaway, J.S., 1977, Map and table describing known metalliferous and selected nonmetalliferous mineral deposits in central Alaska: U.S. Geological Survey Open-File Report 77-168-D, 132 p., 1 sheet, scale 1:1,000,000. Mertie, J.B., Jr., 1936, Mineral deposits of the Ruby-Kuskokwim region, Alaska: U.S. Geological Survey Bulletin 864-C, p. 115-245. Mertie, J.B., Jr., and Harrington, G.L., 1916, Mineral resources of the Ruby-Kuskokwim region, in Brooks, A.H., and others, Mineral Resources of Alaska, Report on Progress of Investigations in 1915: U.S. Geological Survey Bulletin 642-H, p. 223-266. White, M.G., and Stevens, J.M., 1953, Reconnaissance for radioactive minerals in the Ruby-Poorman and Nixon Fork districts, west-central Alaska, in 1949: U.S. Geological Survey Circular 279, 19 pages.