Middleton Island

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold
Gangue minerals garnet

Geographic location

Quadrangle map, 1:250,000-scale MI
Quadrangle map, 1:63,360-scale B-7
Latitude 59.4082
Longitude -146.3647
Nearby scientific data Find additional scientific data near this location
Location and accuracy The beach along the bluffs at the southwest end of Middleton Island was the site of small-scale placer gold mining as early as 1901. This is locality 1 of Cobb (1972 [MF 380]; 1979 [OF 79-1246]). It is accurately located.

Geologic setting

Geologic description

Storm waves concentrate garnet-rich heavy mineral sands that contain small amounts of placer gold along the southwest headland of Middleton Island (Brooks, 1913; Reimnitz and Plafker, 1976). Other beaches around the island may also contain small amounts of placer gold. Some mining occurred as early as 1901, and by 1913, about 400 ounces of gold were estimated to have been produced (Brooks, 1913). The recovered gold was fine and flat; the coarsest grain weighed about 0.05 ounce (Brooks, 1913). Later residents of the Middleton Island military facilities conducted recreational placer gold mining on the island beaches (George Plafker, oral communication, 2001). The gold is derived from the reworking of the marine glacial deposits of the upper Cenozoic Yakataga Formation. These rocks make up the bedrock of Middleton Island and much of the surrounding continental shelf (Reimnitz and Plafker, 1976).
Geologic map unit (-146.366758399568, 59.40761646475)
Mineral deposit model Placer Au (beach) (Cox and Singer, 1986; model 39a)
Mineral deposit model number 39a
Age of mineralization Holocene.

Production and reserves

Workings or exploration Very small scale hand mining recovered a few hundred ounces of gold.
Indication of production Yes; small
Production notes About 400 hundred ounces of gold were estimated to have been recovered between 1901 and 1913 (Brooks, 1913).

References