Won - North

Prospect, Active

Alternative names

Stockwork Zone
Standoff Ridge

Commodities and mineralogy

Main commodities Ag; Sn
Other commodities As; Cu; Pb; Sb; Zn
Ore minerals arsenopyrite; cassiterite; chalcopyrite; sphalerite; tetrahedrite
Gangue minerals axinite; quartz; tourmaline

Geographic location

Quadrangle map, 1:250,000-scale MD
Quadrangle map, 1:63,360-scale C-6
Latitude 63.504
Longitude -155.696
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Won - North prospect is situated on a north-facing slope near the summit of a north-south trending ridgeline at an elevation of 2,300 feet (701 m) in Section 12, T. 23 S., R. 16 E., of the Kateel River Meridian. Mineralization in the Standoff Ridge Zone of the Won - North prospect is about 2.1 miles (3.4 km) North of the Won - South prospect (MD024). Location is accurate; the reporter visited the site in 1984.

Geologic setting

Geologic description

The Won - North prospect is the northern-most group of silver-tin prospects that have been referred to by Burleigh (1992; BMOF 85-92) as the 'Won' deposit. Mineralization occurs as moderately dipping breccia vein structures in thermally altered rocks of the Upper Cretaceous Kuskokwim Group. The Stockwork zone consists of stockwork quartz veining and crosscutting tourmaline breccias that can be traced on the surface for about 1,000 feet (300 m) by 250 feet (76 m). Small 0.5 to 2 inch (1.2 to 5.0 cm) thick quartz veinlets occur often, with a density of 30 per foot (0.3 m). The Standoff Ridge Zone is a series of four or more north 25 degrees west -trending vein structures that can be traced for about 1,500 feet (457 m).
Arsenopyrite and cassiterite are the dominant ore minerals found in the various zones. Age of mineralization is inferred to be Late Cretaceous-Early Tertiary, based on ages of nearby plutonic rocks (Bundtzen and Miller, 1997). Anaconda Mineral Company drilled the property in 1984 and encountered up to 0.14 percent tin and 4.6 ounces/ton silver over narrow, sheeted veins up to six feet (1.8 m) wide.
Geologic map unit (-155.698366186645, 63.503392512077)
Mineral deposit model Tin-polymetallic (Cox and singer, 1986; model 20b).
Mineral deposit model number 20b
Age of mineralization Late Cretaceous-early Tertiary, inferred based on ages of nearby plutonic rocks (Bundtzen and Miller, 1997).
Alteration of deposit Axinite and sericite.

Production and reserves

Workings or exploration The U.S. Geological Survey AMRAP program of the Medfra quadrangle (King and others, 1980, 1983; Patton and others, 1980) reported anomalous values of arsenic, bismuth, tin, silver, tungsten, and lead in stream sediment and pan concentrate samples from streams draining the project area. Duval Corporation and Anaconda Minerals Company followed up on these anomalies and found the Won-North prospect. In 1984, Anaconda Minerals company drilled the Standoff Ridge zone, and encountered up to 0.14 percent tin and 4.6 ounces/ton silver over narrow, sheeted veins up to 6 feet (1.8 m) wide. Online Exploration Services Inc., Anchorage, Alaska, has continued exploration at the Won-North prospect in recent years.
Indication of production None
Reserve estimates No reserves were calculated from the drill program.

Additional comments

See: Won - South (MD024) and Gemini (MD023) prospects.

References

MRDS Number 10307774

References

Bundtzen, T.K., and Miller, M.L., 1997, Precious metals associated with Late Cretaceous-early Tertiary igneous rocks of southwestern Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 242-286.
Reporters Bundtzen, T.K. (Pacific Rim Geological Consulting)
Last report date 6/3/1998