Mallard Group

Prospect, Inactive

Commodities and mineralogy

Main commodities Au; Cu
Ore minerals chalcopyrite; gold; native copper; pyrite; pyrrhotite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale B-3
Latitude 60.2735
Longitude -147.8296
Nearby scientific data Find additional scientific data near this location
Location and accuracy The prospect is located about a mile south-southwest of the head of Mallard Bay, Knight Island, at 1,500 feet elevation. It is in the SE1/4 section 11, T. 2 N., R. 9 E., of the Seward Meridian. This is location 236 of Cobb and Tysdal (1980) and location S-43 of Jansons and others (1984). This location is accurate to within 300 feet.

Geologic setting

Geologic description

The deposit consists of auriferous, sulfide-bearing quartz veinlets hosted in sheared greenstone and sheeted basalt of the Orca Group of early Tertiary age (Cobb and Tysdal, 1980). The main shear zone is approximately 20 feet wide; it strikes N 35-80 E and dips 60-70 NW. The shear zone is cut by a series of smaller shear zones that trend west to northwest and dip steeply. These smaller zones vary from 1 foot to more than 5 feet in width and contain quartz veinlets. They are intermittently exposed along the bluff for approximately 200 feet. The bluff is the footwall of the main shear zone. Sulfide minerals, primarily pyrrhotite and pyrite, occur as dissemination and stringers within the shear zone. Traces of gold, chalcopyrite, and native copper also occur in the zone. Four random chip samples and two chip samples collected from the prospect by the U.S. Bureau of Mines in the early 1980s contained between 21 ppm and 2.0 percent copper and as much as 3.32 ppm silver (Kurtak and Jeske, 1986).
Geologic map unit (-147.831672719435, 60.2729449916825)
Mineral deposit model Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)
Mineral deposit model number 36a
Age of mineralization Tertiary or younger; the veins cut rocks of the Orca Group of Tertiary age.

Production and reserves

Workings or exploration The workings consisted of a shallow shaft and several prospect pits (Johnson, 1919 8 [B 662-C, p. 217]). In the early 1980s, U.S. Bureau of Mines collected six samples from the prospect that contained between 21 ppm and 2.0 percent copper and as much as 3.32 ppm silver (Kurtak and Jeske, 1986). They did not locate the shaft that was reported by Johnson, but did find several small open cuts.
Indication of production None

References

References

Reporters Jeff A. Huber and Carol S. Huber (Anchorage)
Last report date 12/14/2001