Tolstoi

Prospect, Active

Commodities and mineralogy

Main commodities Ag; As; Cu
Other commodities Au; Be; Bi; Cd; Pb; Sb; Sn; Te
Ore minerals arsenopyrite; boulangerite; chalcopyrite; galena; pyrite; stromeyerite
Gangue minerals axinite; fluorite; quartz; tourmaline; white mica

Geographic location

Quadrangle map, 1:250,000-scale ID
Quadrangle map, 1:63,360-scale D-2
Latitude 62.91543
Longitude -156.98975
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Tolstoi prospect is at an elevation of about 3,400 feet on a steep saddle at the head of one of the headwater tributaries of Tolstoi Creek. It is about 0.5 mile south-southeast of peak 3970 and 0.1 mile northwest of the southeast corner of section 26, T. 33 N., R. 41 W., of the Seward Meridian. The location is accurate.

Geologic setting

Geologic description

The Tolstoi prospect consists of several tabular-to-pipe- shaped, sulfide-bearing, tourmaline-quartz breccia zones in a cupola of the 70.3 Ma, Beaver Mountains stock (Bundtzen and Laird, 1982; Bundtzen and Miller, 1997; Miller, Bundtzen, and Gray, 2005). The tourmaline-axinite-quartz breccia bodies are 6 to 65 feet thick and contain 1 to 8 percent arsenopyrite, chalcopyrite, and pyrite. Stromeryite and boulangerite, possibly the source of the high silver values in samples, have been identified in polished sections. The Tolstoi prospect is similar to a nearby unnamed prospect (ID006) although the sulfides at the Tolstoi prospect are more disseminated and the boron metasomatism in the form of tourmaline and axinite is more extensive. Grab samples of the mineralization at the Tolstoi prospect contained up to 10.0 percent copper, 500 parts per million (ppm) silver, 2.0 percent arsenic, more than 2.0 percent lead, 2.0 percent zinc, 1.0 percent antimony, 1,400 parts per billion (ppb) gold, 39 ppm bismuth, 200 ppm cadmium, and 200 ppm tin (McGimsey and others, 1988; Bundtzen and Laird, 1982). Grab samples collected by Battle Mountain Mining Company in 1990 contained up to 1,137 ppb gold, 86.1 ppm silver, 2.03 percent lead, more than 2.00 percent arsenic, and 81 ppm tin (Szumigala, 1993).
In 2007, Alaska Ventures, Inc. (Bundtzen, 2008) staked 84 Alaska mining claims that covered much of the north-central Beaver Mountains and most of the high-grade copper-silver-gold(-tin) prospects and occurrences in the area. Two high-grade samples were analyzed that came from veinlets in the Tolstoi deposit. They contained 3.09 to 4.43 grams of silver per ton, 5.91 to 87.3 grams of bismuth per ton, and 0.13 to 7.17 grams of tellurium per ton. The high bismuth and tellurium values suggest silver-rich zones in the deposit.
Geologic map unit (-156.992107635887, 62.9147749504955)
Mineral deposit model Sn-polymetallic veins (Cox and Singer, 1986; model 20b).
Mineral deposit model number 20b
Age of mineralization Undated; may be related to emplacement of the Beaver Mountains stock, which has been dated at 70.3 Ma. (Bundtzen and Laird, 1982).
Alteration of deposit Extensive greisen development marked by tourmaline, quartz, white mica, and fluorite.

Production and reserves

Workings or exploration The prospect was mapped and sampled by the Alaska Division of Geological and Geophysical Surveys and the U.S. Geological Survey from 1979 to 1986. Anaconda Minerals Company sampled and mapped the prospect in 1981 (D. Obolewicz, oral communication, 1981). Noranda Exploration examined the property in 1983 (John Dunbier, oral communication, 1983). The prospect was studied by Battle Mountain Mining Company in 1990 (Szumigala, 1993,1996). In 2007, Alaska Ventures, Inc. (Bundtzen, 2008) staked 84 Alaska mining claims that covered much of the north-central Beaver Mountains and most of the high-grade copper-silver-gold(-tin) prospects and occurrences in the area, including the Tolstoi deposit.
Indication of production None

References

References

Bundtzen, T.K., 2008, Tolstoi-A Promising copper-silver-polymetallic project ready for exploration and drill testing in 2008: Unpublished report for Alaska Ventures, Inc. by Pacific Rim Geological Consulting, Inc., Fairbanks, Alaska, 7 pages.
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.
Szumigala, D.J., 1993, Gold mineralization related to Cretaceous-Tertiary magmatism in the Kuskokwim Mountains of west-central and southwestern Alaska: Los Angeles, University of California Ph.D. dissertation, 300 p.
Szumigala, D.J., 1996, Gold mineralization related to Cretaceous-Tertiary magmatism in west-central Alaska-A geochemical model and prospecting guide for the Kuskokwim region: Geological Society of Nevada Symposium Proceedings, p. 1317-1340.
Reporters T.K. Bundtzen (Pacific Rim Geological Consulting, Inc.), M.L. Miller (U.S. Geological Survey); C.C. Hawley (Hawley Resource Group); D.J. Grybeck (Port Ludlow, WA)
Last report date 6/5/2008