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

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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).

Mineral List



6 entries listed. 6 valid minerals.

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References

Chapman, R.M., and Foster, R.L., 1969, Lode mines and prospects in the Fairbanks district, Alaska: U.S. Geological Survey Professional Paper 625-D, 25 p., 1 plate. Cobb, E.H., 1972, Metallic mineral resources map of the Livengood quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-413, 2 sheets, scale 1:250,000. Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Livengood quadrangle, Alaska: U.S. Geological Survey Open-File Report 76-819, 241 p. Forbes, R.B., Pilkington, H.D., and Hawkins, D.B., 1968, Gold gradients and anomalies in the Pedro Dome-Cleary Summit area, Fairbanks district, Alaska: U.S. Geological Survey Open-File Report 324 (68-108), 43 p. Freeman, C.J., 1992, 1991 Golden Summit project final report, volume 2: Historical summary of lode mines and prospects in the Golden Summit project area, Alaska: Avalon Development Corp., 159 p. (Report held by Freegold Recovery Inc. USA, Vancouver, British Columbia.) Killeen, P.L., and Mertie, J.B., 1951, Antimony ore in the Fairbanks District, Alaska: U.S. Geological Survey Open-File Report 51-46, 43 p. Smith, P.S., 1913, Lode mining near Fairbanks, in Prindle, L.M., A geologic reconnaissance of the Fairbanks quadrangle, Alaska: U.S. Geological Survey Bulletin 525, p. 153-216. Smith, P.S., 1913, Lode mining near Fairbanks: U.S. Geological Survey Bulletin 542-F, p. 137-202. Times Publishing Company, 1912, Tanana Magazine, Quartz Edition: Fairbanks, Alaska, Times Publishing Company, 76 p.

 
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