Grubstake Creek

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Hg; W
Ore minerals cinnabar; gold; scheelite

Geographic location

Quadrangle map, 1:250,000-scale FB
Quadrangle map, 1:63,360-scale A-3
Latitude 64.03
Longitude -148.206
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Grubstake Creek mine is loated in sections 19, 20, and 29, T. 10 S., R. 3 W., Fairbanks Meridian. Placer mines on Grubstake Creek are marked in the southeast corner of the Fairbanks A-3 topographic map; the coordinates are the mine marked near the mouth of the creek. The mine is localities 77, 78, and 79 of Cobb (1972 [MF 410].

Geologic setting

Geologic description

The upper half of Grubstake Creek valley is incised into thick Nenana Gravel; the lower half of the creek has eroded through the base of the Nenana Gravel to a depth of 100 feet or more into semiconsolidated sediments composed of interbedded clay, sand, and gravel, and some thin beds of lignite (Maddren, 1918, p. 399). Since its discovery in 1905, Grubstake Creek has been a major producer of placer gold in the Tatlanika basin. Mining began as early as 1905 and continued intermittently until at least 1940 (Cobb, 1976 [OFR 76-662, p. 44]). Gold is found as small, worn, flat pieces in the bottom two feet of gravel or on the clay bedrock (Prindle, 1907). The gold varies from 817 to 842 fine (Glover, 1950). The gravels are as much as 6 feet thick and include clasts of schist, quartzite, and vein quartz (Prindle, 1907). Scheelite and cinnabar have been found in placer concentrates (Joesting, 1942 [ATDM Pamph. 1, p. 27]).
Geologic map unit (-148.208338280265, 64.0295562394141)
Mineral deposit model Placer Au (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a
Age of mineralization Quaternary placer.

Production and reserves

Workings or exploration Mining began as early as 1905 and continued intermittently until at least 1940 (Cobb, 1976 [OFR 76-662, p. 44]). In 1924, three men mined on the creek with an automatic dam (Wimmler, 1925 [ATDM MR 195-8, p. 43]).
Indication of production Yes; small
Production notes There is no record of the amount of gold that was produced.

References

MRDS Number A015354; D002634

References

Malone, Kevin, 1965, Mercury in Alaska, in Mercury potential of the United States: U.S. Bureau of Mines Information Circular 8252, p. 31-59.
Reporters J.R. Guidetti Schaefer and C.J. Freeman (Avalon Development Corporation)
Last report date 7/31/2001