East Scrafford Prospect, Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi

Regional Level Types
East Scrafford Prospect	Prospect
Fairbanks Mining District	Mining District
Fairbanks North Star Borough	Borough
Alaska	State
USA	Country

Location: The East Scrafford prospect is about 1,900 feet east of the Scrafford mine (FB077); it is located just north of Old Murphy Dome Road in the NE1/4 SE1/4 sec. 16, T. 2 N., R. 1 W., Fairbanks Meridian.
Geology: The following geologic description is summarized from a report by Sam Dashevsky (1993) on work done by American Copper and Nickel Company on the Eagle Creek property in the early 1990's. In the shallow subsurface at this prospect, a 30-foot-thick, medium-grained, equigranular granite and quartz porphyry sill intrudes quarz-mica schist and micaceous quartzite. The intrusion is truncated by a major fault, believed to be the eastern extension of the Scrafford shear zone (see FB077). The Scrafford shear trends N. 80-85 E. and dips 55-60 S. (Robinson and Bundtzen,1982). The upper intrusive contact is irregular and sub-horizontal and lies under 10 feet of schist and 4 feet of loess. At the surface, chip samples across the 30-foot exposure of the intrusion, are enriched in gold and arsenic; the samples average 0.024 ounce of gold per ton and 2,060 to 6,490 ppm arsenic. No significant antimony values are reported. Schist in the wallrock is weakly to unmineralized. The Scrafford shear contains as much as 350 ppb gold, 2,480 ppm arsenic, and 102 ppm antimony. Drilling indicated that the quartz porphyry sill does not exceed 210 ppb gold. The deeper intersection of the sill and the shear, which is composed largely of intrusive and quartz clasts in gouge, averages 0.029 ounce of gold per ton over 35 feet and 0.1 to 1.0 percent arsenic. The intrusive at the surface is moderately to strongly silicified, locally bleached, and iron stained. The schist country rock is strongly silicified at the intrusive contact. Downhole, the sill is cut by sparse, hairine quartz veinlets. In the shear zone, intrusive fragments are highly silicified and locally altered to clay.
Workings: In the 1970's, Cantu Minerals Association trenched at the East Scrafford site in pursuit of the eastern extension of the Scrafford shear (FB077). In 1991-93, American Copper and Nickel Company mapped the trench exposure, took soil samples, and drilled two reverse-circulation holes (Dashevsky, 1993). The gold assays of samples did not encourage them to continue.
Alteration: The intrusive at the surface is moderately to strongly silicified, locally bleached, and iron stained. The schist country rock is strongly silicified at the intrusive contact. Downhole, the sill is cut by sparse hairline quartz veinlets. In the shear zone, intrusive fragments are highly silicified and locally altered to clay (Dashevsky, 1993).

Commodities (Major) - Au
Development Status: None

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Link to USGS - Alaska:	FB078

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References