Harris and Brown; Sky High; Grace E#1 Prospect, Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi

Regional Level Types
Harris and Brown; Sky High; Grace E#1 Prospect	Prospect
Fairbanks Mining District	Mining District
Fairbanks North Star Borough	Borough
Alaska	State
USA	Country

Location: Cobb (1972, MF-413), loc. 44; SW1/4SE1/4 sec. 20, T. 3 N., R. 2 E., of the Fairbanks Meridian. This prospect is on the summit of the divide between Chatham and Wolf Creeks; it is at an elevation of 2,050 feet, between the two northernmost pinnacles of schist. Accuracy is within 1,000 feet.
Geology: Mineralization consists of stibnite filling open fractures and a small proportion of sulfides (Smith, 1913; B 525). Minor amounts of jamesonite, arsenopyrite, pyrite and zinkenite(?) also were identified (Chapman and Foster, 1969). By 1912, a 60-foot-deep shaft had been sunk and 120 feet of drift had been driven at the 60-foot-level. Stoping of ore began in December, 1912. A 6- to 30-inch wide brecciated and quartz-cemented shear zone in the shaft trends N 70 E and dips 45 S (Times Publishing Company, 1912, p. 64). Assays from the development muck ranged from $28 to $130 per ton in gold (1.3 to 6.3 ounces of gold per ton) and average $30 per ton (1.4 ounces of gold per ton). Cobb (1976, p. 80) noted that Grace E #1 is probably the same ground as Harris and Brown or Sky High. Forbes and others (1968) reported that the Grace E #1 prospect opened two small quartz veins that carry 2%-3% sulfides (including arsenopyrite and minor pyrite) and free-milling gold. An unaltered schist 9 feet into the hanging wall assayed 1.3 ppm gold.
Workings: By 1912, a 60-foot-deep shaft had been sunk and 120 feet of drift had been driven at the 60 foot level (Times Publishing Company, 1912, p. 64). Stoping of ore began in December, 1912.

Commodities (Major) - Au; (Minor) - Sb
Development Status: Yes; small
Deposit Model: Polymetallic vein (Cox and Singer, 1986; model 22c).

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Link to USGS - Alaska:	LG145

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References