Unnamed (northeast side of West Fork Rainy Creek)

Prospect, Undetermined

Commodities and mineralogy

Main commodities Ag; Au; Cu; Zn
Ore minerals chalcopyrite; gold; magnetite; malachite; pyrite; pyrrhotite
Gangue minerals amphibole; calcite; epidote; garnet; pyroxene; quartz

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale B-4
Latitude 63.3036
Longitude -145.984
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is at an elevation of about 4,200 feet on the north side of West Fork Rainy Creek. It is about 0.7 mile northwest of the center of section 2 T. 19 S., R. 9 E.

Geologic setting

Geologic description

Mineralization in Rainy Creek has been known since 1916 (Brooks, 1918; Martin, 1920). There has been some hand trending of unknown age at this prospect and it was covered by regionally extensive claims staked by MAN Resources as of 2007. It was examined and sampled in several episodes by state and federal agencies from 1964 to the 2000s.
The prospect is in Pennsylvanian to Permian limestone to limey sedimentary rocks of the Slana Spur Formation (Rose, 1965; Nokleberg and others, 1992 [MF]; 1992 [Open-File]; Bittenbender and others, 2007).
The mineralization is associated with a band of magnetite-pyroxene-garnet skarn about 200 feet long. The limestone adjacent to the skarn is bleached and silicified. There is a gabbro dike nearby that may be related to the nearby Late Triassic Rainy mafic-ultramafic complex. Chalcopyrite occurs widely in the skarn in small amounts and there are lenses of sulfides made up mainly of pyrrhotite, pyrite, and chalcopyrite. Rose (1965) collected a sample of skarn that contained 0.42 percent copper, 0.01 ounce of gold per ton, and 0.40 ounce of silver per ton. The U.S. Geological Survey collected grab samples that contained up to 5.6 percent copper, 0.07 percent zinc, 0.009 ounce of silver per ton, and 0.035 ounce of gold per ton (Nokleberg and others, 1991). Bittenbender and others (2007) collected a sample from a pile of massive-sulfide rubble that contained 2.49 parts per million (ppm) gold, 4,770 ppm copper, and 3.4 ppm silver.
Geologic map unit (-145.986260237916, 63.3031812299759)
Mineral deposit model Silver-gold-copper skarn near a Triassic mafic-ultramafic complex.
Age of mineralization Perhaps related to a nearby Triassic mafic-ultramafic complex.
Alteration of deposit Mineralization associated with a band of magnetite-pyroxene-garnet skarn.

Production and reserves

Workings or exploration The mineralization at this prospect has been known since 1916 (Brooks, 1918; Martin, 1920). There has been some hand trending of unknown age on it and it was covered by regionally extensive claims staked by MAN Resources as of 2007. It was examined and sampled several times by state and federal agencies from 1964 to the the 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