Birch Creek

Mine, Probably inactive

Commodities and mineralogy

Main commodities Au; Sn
Other commodities Ag; Bi; Th; U
Ore minerals anatase; cassiterite; gold; hematite; ilmenite; malachite; native bismuth; pyrite; titanite; uranothorite
Gangue minerals allanite; garnet; zircon

Geographic location

Quadrangle map, 1:250,000-scale RB
Quadrangle map, 1:63,360-scale B-5
Latitude 64.45805
Longitude -155.35305
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.

Geologic setting

Geologic description

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.

Production and reserves

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.

References

MRDS Number A015531

References

Reporters C.E. Cameron (Alaska Division of Geological and Geophysical Surveys)
Last report date 3/22/2000