|Quadrangle map, 1:250,000-scale||RB|
|Quadrangle map, 1:63,360-scale||B-5|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||Birch Creek is a headwater tributary of the Sulatna River. Coordinates corresponding to location 9 of Cobb (1972 [MF405]) are listed above, and mark the approximate center of mining activity, in section 7, T. 12 S., R. 18 E. of the Kateel River meridian. The location is accurate.|
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).
|Geologic map unit||(-155.355478881215, 64.4574487575193)|
|Mineral deposit model||Placer Au (Cox and Singer, 1986; model 39a).|
|Mineral deposit model number||39a|
|Age of mineralization||Quaternary.|
|Workings or exploration||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).|
|Indication of production||Yes; small|
|Production notes||An unknown (probably small) quantity of placer gold was recovered from this creek.|
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.
|Reporters||C.E. Cameron (Alaska Division of Geological and Geophysical Surveys)|
|Last report date||3/22/2000|