Headwall Prospect, Aniak Mining District, Bethel Census Area, Alaska, USAi

Regional Level Types
Headwall Prospect	Prospect
Aniak Mining District	Mining District
Bethel Census Area	Census Area
Alaska	State
USA	Country

Location: This prospect is in the Russian Mountains on the northeast flank of the sharp ridge between the headwaters of Cobalt and Mission Creeks. The map site is in the SW1/4 sec. 8, T. 18 N., R. 54 W., of the Seward Meridian. It is at an elevation of about 2,350 feet, about 0.15 mile south-southwest of a small cirque-basin lake. It is sample locality 14 of Bundtzen and Laird (1991).
Geology: The Headwall prospect is in syenite and includes several 10-foot wide banded tourmaline greisen zones that trend northwest for a distance of at least 790 feet (Bundtzen and Laird, 1991). The zones are exposed over a vertical range of 400 feet. The tourmaline greisens contain euhedral quartz, along with sericite and sulfide veinlets and clots. Arsenopyrite, native bismuth, pekoite, galena, bindheimite, and scorodite have been identified in the sulfide-rich assemblages (Bundtzen and Laird, 1991). The sulfide-bearing zones are disrupted by later faulting. Six channel samples average 3.3 ppm gold, 7.32 percent arsenic, 0.16 percent antimony, and 0.04 percent tin. Bismuth, copper, and lead analyses are not available. Assuming dimensions, in feet, of 4.45 x 400 x 790, Bundtzen and Laird (1991) estimated a resource of 82,900 tons of material with the stated average grades. The host rocks are part of the Upper Cretaceous intrusive complex of the Russian Mountains.
Workings: Surface observation and sampling has been completed (Bundtzen and Laird, 1991).
Age: Late Cretaceous or Tertiary. Greisens crosscut part of the intrusive complex of the Russian Mountains. Quartz monzonite from this complex has yielded a K/Ar age of 70.3 +/- 2.1 Ma (Bundtzen and Laird, 1991).
Alteration: Silicification and tourmalinization.
Reserves: Assuming dimensions, in feet, of 4.45 x 400 x 790, Bundtzen and Laird (1991) estimate a resource of 82,900 tons of material with average grades of 3.3 ppm gold, 7.32 percent arsenic, 0.16 percent antimony, and 0.04 percent tin. Bismuth, copper, and lead analyses are not available.

Commodities (Major) - Au, Sb, Sn; (Minor) - Cu, Pb
Development Status: None

Other Databases

Link to USGS - Alaska:	RM018

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References