Summit Hill

Prospect, Active?

Commodities and mineralogy

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

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale A-3
Latitude 63.1312
Longitude -145.4738
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Summit Hill prospect is at an elevation of 3,600 feet, 0.75 mile east of mile 195 on the Richardson Highway. It is at the northeast corner of section 5, T. 20 S., R. 12 E.

Geologic setting

Geologic description

The Summit Hill prospect was discovered and claimed in about 1998 by American Copper and Nickel Company (ACNC). It was restaked by Nevada Star Resource Corp. in 2003 and claims were active as of 2005.
An airborne geophysical survey over the region area defined a circular core zone mainly of biotite diorite with a low magnetic response and a surrounding magnetic high of pyroxene hornblendite and associated mafic-ultramafic rocks (Burns and Clautice, 2003). Bittenbender and others (2007) dated the diorite as 123.2 +/- 1.1 Ma by 40Ar/39Ar methods and the mafic-ultramafic rocks as 123.4 +/-1.3 Ma. Olivine in the mafic-ultramafic rocks is partly serpentinized, and the pyroxene is mostly altered to amphibole. There is also local iron staining.
An ACNC sample of mineralized, medium grained to pegmatitic olivine gabbro with magnetite, chalcopyrite, pyrrhotite, and pentlandite contained 1.07 percent copper, 1.58 percent nickel, 484 parts per billion (ppb) palladium, 300 ppb platinum, and 110 ppb gold (W.T. Ellis, oral communication, 1998). Bittenbender and others (2007) examined and sampled the prospect. Two samples of pyroxenite with 20-30 percent magnetite and minor chalcopyrite were from near the ACNC discovery. The highest metal values were less than 5 ppb platinum, 29 ppb palladium, 195 parts per million (ppm) copper, and 55 ppm nickel. They collected one sample of gabbro and two samples of diorite at the contact of the diorite and the mafic-ultramafic rocks. The highest metal content in them was 22 ppb gold and 495 ppm copper.
Geologic map unit (-145.47602591624, 63.1307843740159)
Mineral deposit model Copper-nickel-PGE mineralization associated with a diorite surrounded by mafic and ultramafic rocks.
Age of mineralization Mid-Early Cretaceous (123 Ma) based on 40Ar/39Ar analyses.
Alteration of deposit Olivine is partly serpentinized, and the pyroxene is mostly altered to amphibole. There is also local iron staining.

Production and reserves

Workings or exploration The Summit Hill prospect was discovered and claimed in about 1998 by American Copper and Nickel Company (ACNC). It was restaked by Nevada Star Resource Corp. in 2003 and claims were active as of 2005. A 2003 airborne geophysical survey covered the area. 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

Bittenbender, P.E., Bean, K.W., Kurtak, J.M., and Deininger, James Jr., 2007, Mineral assessment of the Delta River Mining District area, east-central, Alaska: U.S. Bureau of Land Management, Alaska Technical Report 57, 675 p.
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