Mount Ripinski

Prospect, Inactive

Commodities and mineralogy

Main commodities Au; Cu; Fe
Other commodities Pd; Pt
Ore minerals bornite; chalcopyrite; malachite; pyrite; pyrrhotite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale SK
Quadrangle map, 1:63,360-scale B-2
Latitude 59.256
Longitude -135.514
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is on the south side of Mt. Ripinski approximately 0.5 mile south of triangulation station '3563'. It is at an elevation of approximately 1,500 feet near the base of a steep south-facing cliff. Redman and others (1984) show this site as occurrence 1, but they were unable to locate the 100-foot adit reported to occur at this site by Robertson (1956). The location is accurate to within about 0.25 mile.

Geologic setting

Geologic description

The following description is from Still and others (1991). Chalcopyrite-bornite-bearing quartz-calcite veins and chalcopyrite-bearing metabasalt occur in cliffs and in rubble beneath the cliffs on the south side of Mount Ripinski. Almost all of the quartz veins that were sampled contained low gold values, but some veins contained up to 12.0 ppm gold and 3.97% copper. The metabasalt contained up to 0.60 ppm gold and 3.50 % copper. Eighteen of the 27 samples were analyzed for platinum and palladium. They contained from 0.01 to 0.06 ppm palladium and one sample contained 0.01 ppm platinum. This site is immediately north of the Johnson Creek fault which separates metabasalt to the north from Cretaceous ultramafic rocks, including pyroxenite, to the south. Iron deposits associated with pyroxenite are also reported from this general area but no descriptions are given (Redman and others, 1984).
The Cretaceous age of the metabasalts (Still and others, 1991; MacKevett and others, 1974) establishes a maximum age for the mineralization. However, based on fossil evidence from the Chilkat Peninsula to the southeast, Plafker, Hudson and Silberling (1979) and Plafker and Hudson (1980) infer a Late Triassic age for the metabasalts.
Geologic map unit (-135.515830367685, 59.2556725873889)
Mineral deposit model Possible metamorphic quartz-sulfide veins in association with copper rich metabasalts and an iron-rich ultramafic intrusion (Cox and Singer, 1986; model 36a?).
Mineral deposit model number 36a?
Age of mineralization Cretaceous or younger, or Late Triassic or younger (Plafker, Hudson and Silberling, 1979; Plafker and Hudson, 1980).

Production and reserves

Workings or exploration Redman and others (1984) refer to a report by Robertson (1956) of a 100-foot adit but were unable to find it.
Indication of production None
Reserve estimates Robertson (1956) indicates that several billion tons of material with 2 to 10% iron may exist in this area.

References

MRDS Number 10308241

References

Plafker, George, and Hudson, T., 1980, Regional implications of Upper Triassic metavolcanic and metasedimentary rocks on the Chilkat Peninsula, southeastern Alaska: Canadian Journal of Earth Sciences, v. 17, p. 681-689.
Reporters T.C. Crafford (T. Crafford & Associates, Anchorage)
Last report date 2/4/2001