Miyaoka West Prospect, Bonnifield Mining District, Southeast Fairbanks Census Area, Alaska, USAi

Regional Level Types
Miyaoka West Prospect	Prospect
Bonnifield Mining District	Mining District
Southeast Fairbanks Census Area	Census Area
Alaska	State
USA	Country

Location: The Miyaoka West prospect is located in the headwaters of an unnamed east fork of Whistler Creek at an elevation of about 4,500 feet. The prospect, located here at the approximate midpoint of a southeast-trending mineralized zone about a mile long, is about 750 feet west of the center of section 10, T. 14 S., R. 5 E., Fairbanks Meridian.
Geology: Rocks at the Miyaoka West prospect consist of complexly deformed greenstone, chlorite schist, and calc-schist of Devonian age (Nokleberg and Aleinikoff, 1985; Lange and others, 1993). The deposit is generally stratabound and consists mainly of pyrrhotite and pyrite. Chalcopyrite, sphalerite, and galena locally occur in fairly sparsely distributed pods, disseminations, and vein-like zones. The pods are as much as about 3 feet across. Samples collected during a 1980's U.S. Geological Survey reconnaissance contained as much as 0.5 percent zinc, 0.43 percent copper; and 0.017 percent lead. Trace elements in the mineralized rocks include as much as 50 parts per million (ppm) tin, 0.2 ppm gold, and 500 ppm cobalt (Nokleberg and others, 1991).
Workings: Re-examination of the prospect by American Copper and Nickel Company in 1993 indicated that pyrrhotite is the main sulfide and that base metal concentrations are generally low (W.T. Ellis, unpublished data, 1993).
Age: Devonian, the age of the host strata.

Commodities (Major) - Cu, Zn; (Minor) - Ag, Au, Co, Pb, Sn
Development Status: None
Deposit Model: Kuroko massive sulfide (Cox and Singer, 1986; model 28a).

Other Databases

Link to USGS - Alaska:	MH005

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References