Prospect, Active

Commodities and mineralogy

Main commodities Ni; Pd
Other commodities Cu; Pt
Ore minerals chalcopyrite; pentlandite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale B-5
Latitude 63.2515
Longitude -146.1632
Nearby scientific data Find additional scientific data near this location
Location and accuracy The LFF prospect is at an elevation of 3,750 feet on the north-facing slope of a hill one mile south of Eureka Creek. It is 2.1 miles southwest of the confluence of Eureka Creek and stream in Broxson Gulch. The prospect is in the SW1/4 section 23, T.19 S., R. 8.E., Fairbanks Meridian. The location is accurate within two-tenths of a mile.

Geologic setting

Geologic description

The LFF prospect is hosted by the Fish Lake mafic-ultramafic intrusive complex, which is Late Triassic in age and is believed to be a lopolithic feeder of the Nikolai basalt flows (Nokleberg and others, 1991). The prospect is poorly exposed; rubble and subcrop of pyroxenite and feldspathic peridotite probably are from the top of the first magmatic cycle of the Fish Lake complex (W.T. Ellis, unpublished data, 1996). The ultramafic rocks contain disseminations of pyrrhotite, chalcopyrite, and pentlandite; grab samples assay as much as 1.05 percent nickel, 0.19 percent copper, 1,580 parts per billion palladium, and 80 parts per million platinum (W.T. Ellis, unpublished data, 1996).
Geologic map unit (-146.165458199549, 63.2510763748822)
Mineral deposit model Ni-Cu-PGE in differentiated mafic-ultramafic sill.
Age of mineralization Late Triassic, the age of the host rock.

Production and reserves

Workings or exploration The occurrence is on active Fort Knox Gold Resource claims. Grab samples contained as much as 1.05 percent nickel and 1,580 parts per billion palladium.
Indication of production None