Won - South

Prospect, Active

Alternative names

Prospect Pit
Dog Day
Tin Ridge

Commodities and mineralogy

Main commodities Ag; Sn
Other commodities As; Cu; Pb; Sb; W; 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 B-6
Latitude 63.482
Longitude -155.717
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Won-South Prospect is located in an inclined saddle on a south facing slope of a small but locally prominent 2,920 foot high mountain range in Section 23, T. 23 S., R. 16 E., of the Kateel River Meridian. The property is at an elevation of 2,350 feet (717 m). The reporter briefly visited the site in 1984.

Geologic setting

Geologic description

The Won - South prospect is one of several argentiferous and stanniferous prospects in a small but prominent mountain upland 10 miles (15 km) east of the Cripple Creek Mountains. The Won-South prospect consists of four or more, northwest trending, breccia-vein structures that cut tourmaline-axinite and quartz-altered hornfels (Burleigh, 1992; Bundtzen and Miller, 1997). The veins strike North 45 degrees West, and dip steeply both in northeast and southwest directions. The largest tin-silver bearing vein at the Won-South prospect is the Dog Day and Gash veins, which could be traced for strike lengths of up to 3,500 feet (1,067 m).
Tin and silver values occur in brecciated hornfels with cassiterite matrix, cassiterite-sulfide druse on fracture surfaces, in open space crackle breccias, and as disseminated cassiterite in quartz veins (Burleigh, 1992, BMOFR 85-92). Host lithologies are thermally altered (hornfels) of shallow marine-to-nonmarine facies of the Upper Cretaceous Kuskokwim Group. The thermal effects are caused by an underlying plutonic body that is manifested in the prospect area by fine grained, northwest trending intermediate dikes. Although some tin was found in the dikes, all significant mineralization thus far found is in the hornfels. Age of mineralization is inferred to be Late Cretaceous-early Tertiary based on age range of plutons in Kuskokwim Mineral belt (Bundtzen and Miller, 1997). In 1984, Anaconda Minerals Company completed two diamond drill holes into the Dog Day and Gash veins and encountered up to 6.90 percent tin and 3.3 ounces/ton silver and highly anomalous antimony, lead, arsenic, copper, and tungsten over unknown widths.
Geologic map unit (-155.719365728656, 63.4813919382442)
Mineral deposit model Tin-polymetallic veins (Cox and Singer, 1986; model 20b).
Mineral deposit model number 20b
Age of mineralization Late Cretaceous-early Tertiary (inferred) based on age range of plutons in Kuskokwim Mineral belt (Bundtzen and Miller, 1997).
Alteration of deposit Sericite-quartz in intermediate dikes.

Production and reserves

Workings or exploration A data release of the U.S. Geological Survey AMRAP study of the Medfra quadrangle (King and others, 1980, 1983b; Patton and others, 1980) reported anomalous tin, tungsten, bismuth, lead, silver, and arsenic in stream sediment and pan concentrate samples from creeks draining the project area. In 1983 Duval Corporation and Anaconda Minerals Inc. followed up on these anomalies and discovered the Won-South lode system. In 1984, Anaconda Minerals completed at least two diamond drill holes into the Dog Day and Gash Veins. Drilling encountered up to 6.9 percent tin and 3.3 ounces/ton silver, and anomalous antimony, lead, arsenic, copper, and tungsten over an undisclosed width. Online Exploration Services, Anchorage, Alaska, continued exploration activities in 1997.
Indication of production None
Reserve estimates Utilizing Anaconda Minerals exploration data and their own surface sampling, Burleigh (1992, BMOFR 85-92) and Bundtzen and Miller (1997) indicate that the Dog Day-Gash Vein system contains 981,875 tons (890,757 tonnes) of ore grading 1.03 percent tin. The average grade for silver, copper, tungsten and other commodities was not calculated.

Additional comments

See: Won - North (MD021), Gemini, (MD023), and Win (MD060) prospects.