MAS/MIL number 20760063.
Location: This prospect is at an elevation of about 2,800 feet, approximately 2 miles east of lower Eldridge Glacier. It is near the head of an unnamed, small south- flowing tributary of Coal Creek, in the SW1/4 sec. 21, T. 22 S., R. 12 W., Fairbanks Meridian. The location is accurate to within 1/4 mile. The area of interest extends 1 mile north and south of this location. This is locality 4 of Csejtey and Miller (1978).
Geology: This deposit consists chiefly of disseminated grains and locally high concentrations of cassiterite in a sheeted vein system; there is also minor disseminated cassiterite. The deposit is within and above an apical dome of greisenized lower Tertiary granite that intrudes older, probably cogenetic, granite (Nokleberg and others, 1987). Cassiterite also occurs in thin quartz-topaz-sulfide veinlets that postdate alteration and in stockwork veinlets. The veins vary in width from hairline to 1 cm, are nearly vertical, and reach a density of 10 veins per meter in the most intensely fractured zones. The veins form a stockwork along a fracture(?) zone in granite in an area of about 4,000 square meters (Gregory Thurow, written commun., 1984). The cassiterite is accompanied by sulfides including arsenopyrite, pyrite, pyrrhotite, and sphalerite. The granite adjacent to the veinlets is pervasively altered to quartz, tourmaline, topaz, sericite, and minor fluorite. The granite intrudes and contact-metamorphoses Devonian argillite, graywacke, and minor limestone. The granite is probably part of the 55 Ma McKinley plutonic suite (Nokleberg and others, 1987). A bulk sample collected by the U.S. Bureau of Mines averaged 0.31 percent tin (Kurtak and others, 1992). Grab samples contain up to 1.5 percent tin (Nokleberg and others, 1987). Samples collected by Reed (1978) contain up to 4.3 ounces of silver per ton. Selected samples collected by Balen (1990) have up to 65 parts per million silver, 0.5 parts per million gold, 328 parts per million lead, 720 parts per million tungsten, and 4.86 percent zinc. Exploration includes surface trenching and extensive diamond drilling by Houston Oil and Minerals, Inc. As of January 1, 2000, a block of 4 state claims covered this prospect (Northern Associates Inc., written commun., 2001).
Workings: Exploration includes surface trenching and extensive diamond drilling by Houston Oil and Minerals, Inc. A bulk sample collected by the U.S. Bureau of Mines averaged 0.31 percent tin (Kurtak and others, 1992). Grab samples contain up to 1.5 percent tin (Nokleberg and others, 1987). Samples collected by Reed (1978) assayed up to 4.3 ounces of silver per ton. Rock Selected samples collected by Balen (1990) assayed up to 65 parts per million silver, 0.5 parts per million gold, 328 parts per million lead, 720 parts per million tungsten, and 4.86 percent zinc. As of January 1, 2000, a block of 4 state claims covered this prospect (Northern Associates Inc., written commun., 2001).
Age: Probably genetically related to Tertiary granite.
Alteration: Sericitization and greisenization of granite (Nokleberg and others, 1987).
Reserves: The deposit is estimated to contain a resource of 5 million tons of material that contain 0.28 percent tin and about 0.5 percent copper (Gregory Thurow, written commun., 1984; Nokleberg and others, 1987).

Commodities (Major) - Sn; (Minor) - Ag, Au, Cu, Mo, W, Zn
Development Status: None
Deposit Model: Tin greisen (Cox and Singer, 1986; model 15c)

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Mineral List

10 valid minerals.