Rainy

Prospect, Active

Alternative names

East Peak

Commodities and mineralogy

Main commodities Cu; Ni; Pd; Pt
Other commodities Au; Co; Cr
Ore minerals chalcopyrite; magnetite; pentlandite; pyrrhotite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale B-4
Latitude 63.3281
Longitude -145.9917
Nearby scientific data Find additional scientific data near this location
Location and accuracy The East Peak prospect is a few hundred feet east of peak 6346 at an elevation of 6,000 feet. It is about 4.0 miles northwest of the mouth of the West Fork of Rainy Creek and about 0.4 mile northeast of the center of section 27, T. 18 S., R. 9 E., of the Fairbanks Meridian. The location is accurate to within 1/4 mile.

Geologic setting

Geologic description

The East Peak prospect is in an Upper Triassic ultramafic-mafic Rainy complex which intrudes the Slana Spur Formation of Pennsylvanian and Permian age (Nokleberg and others, 1992; Nokleberg and others, 1992; Bittenbender and others, 2007). In this area the complex includes a basal layered gabbro sequence as much as 1,500 feet thick; prominent rock types are gabbronorite, coarsely-crystalline clinopyroxene melagabbro, wherlite, and minor serpentinized dunite.
From 1995 to 1999, the prospect was explored by American Copper and Nickel Company (ACNC) working with Fort Knox Gold Resources, Inc. Their work included rock sampling, airborne and ground geophysical surveys, and one diamond drill hole (W.T. Ellis, oral communication, 2001). Active claims were held by MAN Resources through at least 2001.
Mineralization consists of 5 to 15 percent disseminated pyrrhotite with minor chalcopyrite and pentlandite in coarse-grained olivine melagabbro with 15 to 25 percent feldspar. Two rock samples collected by American Copper and Nickel Company contained 0.27 and 0.30 percent copper, 0.13 and 0.08 percent nickel, 84 and 510 parts per billion (ppb) palladium, and 110 and 55 ppb platinum. A sample collected by MAN Resources contained 46 ppb gold, 0.03 percent copper, 0.085 percent nickel, 510 ppb palladium, and 55 ppb platinum (W.T. Ellis, oral communication, 2001).
Bittenbender and others (2007) collected two samples at the prospect and 5 more in the general area. The two samples from the prospect contained up to 100 ppb platinum, 65 ppb palladium, 36 ppb gold, 2,010 parts per million (ppm ) copper, and 1,175 ppm nickel. The five samples nearby contained lesser precious metals but up to 2,590 ppm nickel, 1,090 ppm chromium and 138 ppm cobalt.
In 2011, Pure Nickel Inc. reported a mapping program on the Rainy complex, identifying several gossanous areas at the complex's contact with the sedimentary host rocks. Grab samples from these gossanous contact rocks returned values up to 130 ppb gold, 150 ppb platinum, and 550 ppb palladium. The gossanous zones are interpreted to reflect deposition of sulfides at the basal contact of the Rainy complex and, thus this stratigraphic interval is thought to offer significant potential for economic mineralization (Pure Nickel Inc., 2011).
Geologic map unit (-145.993962697954, 63.3276818875222)
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 (Nokleberg and others, 1992).
Alteration of deposit The olivine melagabbro and dunite are locally serpentinized (Bittenbender and others, 2007).

Production and reserves

Workings or exploration
From 1995 to 1999, the prospect was explored by American Copper and Nickel Company (ACNC) working with Fort Knox Gold Resources, Inc. Their work included rock sampling, airborne and ground geophysical surveys, and one diamond drill hole (W.T. Ellis, oral communication, 2001). Claims held by MAN Resources were active through at least 2001. Examined and sampled by the Bureau of Land Management in the early 2000s.
In 2011, Pure Nickel Inc. reported a mapping program on the Rainy complex, identifying several gossanous areas at the complex's contact with the sedimentary host rocks. Grab samples from these gossanous contact rocks returned values up to 130 parts per billion (ppb) gold, 150 ppb platinum, and 550 ppb palladium. The gossanous zones are interpreted to reflect deposition of sulphides at the basal contact of the Rainy complex and, thus this stratigraphic interval is thought to offer significant potential for economic mineralization (Pure Nickel Inc., 2011).
Indication of production 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); V.C. Zinno (Alaska Earth Sciences, Inc.)
Last report date 12/11/2014