Granite Creek

Mine, Active?

Commodities and mineralogy

Main commodities Au
Other commodities Ag; As; Cr; Hg; W
Ore minerals arsenopyrite; chromite; cinnabar; gold; ilmenite; scheelite

Geographic location

Quadrangle map, 1:250,000-scale ID
Quadrangle map, 1:63,360-scale B-4
Latitude 62.46473
Longitude -157.90003
Nearby scientific data Find additional scientific data near this location
Location and accuracy About 0.8 miles in the middle portion of Granite Creek has been mined and the workings are shown on the USGS 1:63,360-scale topographic map. The center of the workings is at an elevation of about 600 feet in the SE1/4, section 36, T. 28 N., R. 47 W., of the Seward Meridian. The location is accurate. Granite Creek is locality 32 of Cobb (1972 [MF 363]); also described in Cobb (1976 [OFR 76-576]).

Geologic setting

Geologic description

Placer gold has been mined on Granite Creek since 1910 (Mertie, 1936). The deposit developed where the creek dissects mineralized volcanic and plutonic rocks north of Otter Creek (Bundtzen and others, 1992). The gold fineness averages 854 (Mertie, 1936). Heavy minerals identified in concentrates include gold, arsenopyrite, cinnabar, scheelite, chromite, and ilmenite (Mertie, 1936; Bundtzen, Cox and Veach, 1987). The placer gold was very fine grained and shotty; about 1.5 feet of bedrock was dug up to recover the gold (Cobb, 1976 [OFR 76-576]). Granite Creek has produced at least 4,750 ounces of gold and 636 ounces of silver since the early 20th century (Bundtzen and others, 1992; Miller, Bundtzen, and Gray, 2005). These production estimates derived from incomplete mint records are probably conservative.
Geologic map unit (-157.902430858624, 62.4640458813184)
Mineral deposit model Placer Au deposit (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Unknown; probably Quaternary.

Production and reserves

Workings or exploration Mining began on Granite Creek in 1908 using scrapers working in open cuts; the most extensive mining took place between 1924 and 1940 (Cobb, 1976 [OFR 76-576]).
Indication of production Yes
Production notes Granite Creek has produced at least 4,750 ounces of gold and 636 ounces of silver since the early 20th century (Bundtzen and others, 1992; Miller, Bundtzen, and Gray, 2005). These production estimates derived from incomplete mint records are probably conservative.

References

References

Morgan, W., 1992, Synopsis of Granite Creek placer operation, Granite Creek, Iditarod quadrangle, central Alaska, unpublished company report for L.E., and Marilyn Wyrick, 22 p.
Reporters T.K. Bundtzen (Pacific Rim Geological Consulting, Inc.), M.L. Miller (U.S. Geological Survey); and C.C. Hawley (Hawley Resource Group)
Last report date 5/19/2003