Hogatza

Mine, Active?

Alternative names

Hog River
Bear Creek

Commodities and mineralogy

Main commodities Au
Other commodities PGE; REE; Sn; Th; U
Ore minerals cassiterite; gold; platinum group metals; uranothorianite
Gangue minerals epidote; garnet; sphene; zircon

Geographic location

Quadrangle map, 1:250,000-scale HU
Quadrangle map, 1:63,360-scale A-6
Latitude 66.1894
Longitude -155.7148
Nearby scientific data Find additional scientific data near this location
Location and accuracy The placer mine at Hogatza is located on the east side of the Zane Hills along Bear Creek. The coordinates are on Bear Creek near the midpoint of the area of tailings shown on the Hughes A-6 topographic map. The placered area extends up and down Bear Creek for about 1.5 miles.

Geologic setting

Geologic description

Placer mining on Bear Creek began in the early 1900s. A dredge was installed on Bear Creek in 1957 and operated until 1975 (Boswell, 1979). The dredge was reactivated in 1981, deactivated again in 1984, and reactivated in 1990 (Swainbank and others, 2000). The current (2001) operational status of the dredge is not known. The cumulative placer gold production from the Koyukuk-Hughes mining district from 1930 to 1999 is 245,188 ounces (Swainbank and others, 2000). Most of that production is from the dredge at Hogatza. Swainbank and others (1997) reported some production from Hogatza in 1996.
The gold-bearing gravels at the Hogatza mine were derived from glaciofluvial material deposited by outwash streams flowing from a glacier that moved eastward down Clear Creek and into the Bear Creek valley in the early Pleistocene (Miller and Ferrians, 1968). Miller and Ferrians suggest that the source of the gold was mineralization along the contact zone between Upper Cretaceous porphyritic monzonite and Lower Cretaceous andesitic volcanic rock. This contact crosses the upper parts of both Clear and Bear Creeks.
The placer concentrates include several accessory minerals that contain rare earth elements (REE), uranium, and thorium (Staatz and others, 1977). These minerals include zircon, uranothorianite, sphene, garnet, and epidote. Sphene from one sample contained 28,450 ppm REE and 1,400 ppm thorium. There have been reports of platinum-group metals (PGE) and tin in placer concentrate samples collected in the 1920s from the placers on Bear Creek (Cobb, 1973 [B1374]), but Cobb and Miller (1981) indicate that the earlier reports may be incorrect. Placer concentrates stockpiled from dredge operations contain 2.97% uranium, 4.38% thorium, 0.06% lanthanum, 0.21% cerium, 1.73% niobium, 0.05% praseodymium, 0.01% gadolinium, 0.02% yttrium, and less than 0.01% each of neodymium, tantalum, and tin (Barker, 1991). The REE values are relatively low for a dredge concentrate, although the neodymium are unusually high.
Geologic map unit (-155.717451986755, 66.1888396572763)
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 Placer mining on Bear Creek began in the early 1900s. A dredge was installed on Bear Creek in 1957 and operated until 1975 (Boswell, 1979). The dredge was reactivated in 1981, deactivated again in 1984, and reactivated in 1990 (Swainbank and others, 2000). The current (2001) operational status of the dredge is not known.
Indication of production Yes; medium
Production notes The cumulative placer gold production from the Koyukuk-Hughes mining district from 1930 to 1999 is 245,188 ounces (Swainbank and others, 2000). Most of that production is from the dredge at Hogatza. Swainbank and others (1997) reported some production from Hogatza in 1996.

References

MRDS Number A010760; M045382

References

Arctic Environmental Information and Data Center, 1982, Mineral terranes of Alaska: University of Alaska, Fairbanks, 7 sheets, scale 1:1,000,000.
Boswell, J.C., 1979, History of Alaskan Operations of United States Smelting, Refining and Mining Company: University of Alaska, Mineral Industry Research Laboratory, 126 p.
Bottge, R.G., 1988, Maps summarizing land availability for mineral exploration and development in western Alaska, 1986: U. S. Bureau of Mines Open-File Report 14-88, 38 sheets.
Bottge, R.G., 1988, Special publication - Availability of land for mineral exploration and development in western Alaska, 1986: U. S. Bureau of Mines Special Publication, 47 p., 38 sheets.
Heiner, L.E., and Wolff, E.N., 1968, Final Report - Mineral Resources of Northern Alaska, 306 pp.
Reporters J.M. Britton (Anchorage)
Last report date 8/1/2002