McKinley Lake mine, Rilley Group, Lucky Strike prospect, Bear Creek prospect (McKinley Lake gold camp)

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag; As; Sb
Ore minerals native gold; pyrite; stibnite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale CV
Quadrangle map, 1:63,360-scale B-4
Latitude 60.4807
Longitude -145.193
Nearby scientific data Find additional scientific data near this location
Location and accuracy This location includes the McKinley Lake mine, the Rilley Group prospect , the Lucky Strike prospect , and the Bear Creek prospect. The map site is the center of an approximately 0.75 square mile area north of McKinley Lake that contains these mines and prospects. It is in S1/2 sec. 15, T. 16 S., R. 1 E., of the Copper River Meridian. Accuracy of location is within 400 ft. The site corresponds to localities C-6 to C-9 in Jansons and others (1984), and locality 29 in Cobb (1972: MF-392).

Geologic setting

Geologic description

The deposits at this site consist of reportedly auriferous quartz veins in Tertiary Orca Group sedimentary rocks adjacent to the 51.6 Ma McKinley Lake pluton (Winkler and Plafker, 1981). Schrader and Spencer (1901) report that the veins both parallel and cross-cut the bedding in the host rock. They also report large amounts of visible gold in the quartz. Haney and Jansons (1987) report three major quartz veins and quartz stockworks from a few inches up to 40 ft. thick. They note that the veins are parallel to bedding in the host rock. Minerals noted by them include pyrite, stibnite, and gold. Analyses of samples from two adits at McKinley Lake contained 0.005 to 0.107 oz. Au/ton and 0.2 oz. Ag/ton. Samples from the mill site contained 25-50 ppm Au and 2.6 ppm Ag (Jansons and others, 1984). Goldfarb and others (1992) report anomalous values of Ag, As, and Au in concentrate samples from streams draining the nearby granite stock. They consider the granite to be the heat source for the mineralizing event.
Geologic map unit (-145.194996502523, 60.4801715230953)
Mineral deposit model Chugach-type low sulfide Au-quartz veins (Bliss, 1992; Goldfarb and others, 1986)
Age of mineralization Tertiary (51 Ma) based on the age of the mineralizing event (Goldfarb and others, 1992).

Production and reserves

Workings or exploration
Five adits ranging from 18-569 ft.; one shaft and numerous open cuts. Ball mill on site.
Analyses of samples from two adits at McKinley Lake contained 0.005 to 0.107 oz. Au/ton and 0.2 oz. Ag/ton. Samples from the mill site contained 25-50 ppm Au and 2.6 ppm Ag (Jansons and others, 1984). Goldfarb and others (1992) report anomalous values of Ag, As, and Au in concentrate samples from streams draining the nearby granite stock.
Indication of production Yes; small
Production notes 16 oz. Au and 9 oz. Ag apparently produced in the early 1900s (Schrader and Spencer, 1901).

Additional comments

Site is in Chugach National Forest.

References

MRDS Number A010443

References

Goldfarb, R.J., Leach, D.L., Miller, M.L., and Pickthorn, W.J., 1986, Geology, metamorphic setting, and genetic constraints of epigenetic lode-gold mineralization within the Cretaceous Valdez Group, south-central Alaska, in Keppie, J.D., Boyle, R.W., and Haynes, S.J., eds., Turbidite-hosted gold deposits: Geological Association of Canada Special Paper 32, p. 87-105.
Reporters S.W. Nelson, Anchorage, AK
Last report date 6/10/2000