White Band

Prospect, Active

Commodities and mineralogy

Main commodities Au; Cu; Ni; Pd; Pt
Ore minerals chalcopyrite; malachite; pyrite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale B-4
Latitude 63.3179
Longitude -145.9143
Nearby scientific data Find additional scientific data near this location
Location and accuracy The White Band prospect is at an elevation of about 4,800 feet on the east valley wall of upper North Fork Rainy Creek. It is about 2.1 miles north-northwest of the junction of the North and West Forks of Rainy Creek and about 0.6 mile south-southwest of the center of section 30, T. 18 S., R. 10 E.

Geologic setting

Geologic description

The White Band prospect is in the Late Triassic, Rainy mafic-ultramafic complex which intrudes the Slana Spur Formation of Pennsylvanian and Permian age. The complex is up to 5,000 feet thick, dips shallowly north, and can be traced for more than 15 miles; it is mainly serpentinized dunite with subordinate peridotite, pyroxenite, and gabbro (Nokleberg and others, 1992 [MF]; 1992 [Open-File]; Bittenbender and others, 2007). The base of the complex is a layered gabbro as much as 1,500 feet thick.
The White Band prospect was found in the 1990s by American Copper and Nickel Company during their regional exploration for nickel and copper (W.T. Ellis, oral communication, 2001). The prospect consists of 2 to 3 percent of disseminated pyrite, pyrrhotite, and chalcopyrite in a prominent band of white, anorthosite gabbro in a peridotite unit near the southern contact of the Rainy complex. Samples of the sulfide-bearing white gabbro contained 3,688 parts per billion (ppb) gold, 210 ppb palladium, 95 ppb platinum, 0.27 percent copper, and 0.11 percent nickel (W.T. Ellis, oral communication, 2001). Samples of apparently the same rock collected by Bittenbender and others (2007) contained lower precious metal values: up to 16 ppb gold, 74 ppb platinum, 2,700 parts per million (ppm) copper, and 2,030 ppm nickel. They also collected a float sample of iron- and copper-stained melagabbro about 300 feet higher in elevation from the white gabbro that contained 1,070 ppb gold, 227 ppb platinum, 348 ppb palladium, 1,570 ppm copper, and 1,270 ppm nickel.
Geologic map unit (-145.916558748129, 63.3174831157715)
Mineral deposit model Nickel-copper-PGE mineralization in a differentiated mafic-ultramafic complex.
Age of mineralization Genetically related to the emplacement of a Late Triassic mafic-ultramafic complex.
Alteration of deposit The olivine-bearing ultramafic rocks are variably serpentinized; copper minerals are locally oxidized.

Production and reserves

Workings or exploration The White Band prospect was found in the 1990s by American Copper and Nickel Company during their regional exploration for nickel and copper (W.T. Ellis, oral communication, 2001). Examined and sampled by the Bureau of Land Management in the early 2000s.
Indication of production None
Reserve estimates None.
Production notes None.

References

References

Reporters W.T. Ellis (Alaska Earth Sciences), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS); D.J. Grybeck (Contractor, USGS)
Last report date 5/13/2012