Unnamed (southwest coast of Halleck Island)

Prospect, Undetermined

Commodities and mineralogy

Main commodities Au
Ore minerals gold; pyrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SI
Quadrangle map, 1:63,360-scale A-5
Latitude 57.1924
Longitude -135.4634
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is at sea level on the southwest coast of Halleck Island, about 0.9 mile northwest of Krugloi Point. The prospect is 0.4 mile north-northwest of the center of sec. 18, T. 54 S., R. 63 E. It is location P-109 of Bittenbender and others (1999) and MAS no. 0021140152 (U.S. Bureau of Land Management, 2002). The location is accurate within 0.5 mile.

Geologic setting

Geologic description

The rocks in the vicinity of this prospect are Jurassic and Cretaceous, black slate and graywacke, with greenstone and chert bands (Roehm, 1938 [PE 114-10]; Loney and others, 1975). The rocks are locally altered to amphibolite or greenschist with minor phyllite and schist , and often have an intense cataclastic foliation.
This prospect was discovered a few years before 1938 and in 1936, the property was restaked and held by the Baranof Mining Company. The original discovery was said to be a quartz showing 6 feet long and 2 feet wide with visible gold (Roehm, 1938 [PE 114-10]). In 1938, there was considerable activity on the property and 5 men were employed. The machinery included a compressor powered by a gas engine, a hoist, and a jackhammer. The camp consisted of a compressor house, an oil house, a blacksmith shop, a dock house on a scow, a powder house and a bunk house. There is little indication of exploration work after 1939.
The early work was a rock cut 30 feet in length on the original quartz showing that proved to be only a 'small bunch of quartz'. At the time of Roehm's visit in 1938, only a few small quartz veinlets were exposed along a fault zone. The only sulfide in the quartz was sparse pyrite. A tunnel was being driven along the fault zone. Later information indicated that it was driven 66 feet and an 80 foot shaft was being sunk. Only scattered quartz veinlets were cut in the tunnel. A sample 2 feet long with quartz stringers was collected in the tunnel; it had nil gold. Roehm also collected a 54-inch sample across the fault zone that had small quartz veinlets in mineralized slate; it contained 0.02 ounce of gold per ton and nil silver.
Bittenbender and others (1999) collected seven samples of quartz with sheared graywacke; several of the quartz samples had minor pyrite. They contained less than 5 to 295 parts per billion gold, less than 0.2 parts per million silver, and background values of other metals.
Geologic map unit (-135.465167226214, 57.1920435863897)
Mineral deposit model Low-sulfide gold-quartz vein (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a
Age of mineralization Jurassic or younger based on the age of the host rock.

Production and reserves

Workings or exploration Apparently there was little work except from 1937 to 1939 when a substantial camp was on the property. Several trenches were dug, an adit was driven 66 feet, and a shaft was sunk 80 feet.
Indication of production None
Production notes Probably none.

References

References

Bittenbender, P., Still, J.C., Maas, K., and McDonald, M., Jr., 1999, Mineral resources of the Chichagof and Baranof Islands area, southeast Alaska: Bureau of Land Management, BLM-Alaska Technical Report 19, 222 p.
U.S. Bureau of Land Management, 2002, Alaska mineral locations database report (Sitka quadrangle), July 2, 2002, 205 p. [http://imcg.wr.usgs.gov/dem.html]
Reporters Donald Grybeck (U.S. Geological Survey)
Last report date 5/5/2005