Spirit Mountain

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu; Ni
Other commodities Ag; Co; PGE; Zn
Ore minerals bravoite; chalcopyrite; limonite; magnetite; pentlandite; pyrite; pyrrhotite; sphalerite
Gangue minerals antigorite; chlorite; epidote; hornblende; serpentine; talc; tremolite

Geographic location

Quadrangle map, 1:250,000-scale VA
Quadrangle map, 1:63,360-scale B-1
Latitude 61.3056
Longitude -144.2645
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is on the west side of upper Canyon Creek valley about 1.8 miles southwest of the west end of summit Lake and nine-tenths of a mile southeast of elevation 5,990. It is at an elevation of 4,000 feet near center of the east boundary of section 35, T. 6 S., R. 6 E., of the Copper River Meridian. This prospect is probably located to within one-quarter mile. It is locality 61 of Cobb and Matson (1972) and locality 52 of Winkler and others (1981 [OFR 80-892-B]).

Geologic setting

Geologic description

Mafic and ultramafic sill-like bodies that intrude metasedimentary rocks of the Haley Creek terrane contain disseminations and segregations of bravoite, chalcopyrite, pentlandite, pyrite, pyrrhotite, and sphalerite (Kingston and Miller, 1945; Herreid, 1970; Winkler and others, 1981 [OFR 80-892-B]; Winkler and others, 1981 [OFR 80-892-A]). The principal mineralization is in altered peridotite and a nearby hornblendite dike (Herreid, 1970). The peridotite has been altered to antigorite, chlorite, epidote, hornblende, limonite, magnetite, serpentine, tremolite, and talc. One mineralized body is 200 feet long, 1 inch to 22 feet wide, and exposed over 150 feet vertically. Another mineralized body is 45 feet long, 3 feet thick at the surface, but it pinches down to a thickness of 6 inches within 10 feet of the surface (Kingston and Miller, 1946). The resource estimate for these two bodies is 6,500 tons of material that contain 0.22 to 7.61 percent nickel and 0.12 to 1.56 percent copper (Kingston and Miller, 1945, p. 56). The highest values reported for other samples are 1.70 percent nickel and 2.95 percent copper (Pierce, 1945). Heads from a metallurgical sample contained 1.16 percent nickel, 0.76 percent copper, 0.04 percent cobalt, 0.02 percent zinc, 0.007 ounce of gold per ton, 0.077 ounce of silver per ton, 0.006 ounce of platinum per ton, and 0.005 ounce of palladium per ton (Foley and others, 1989). This prospect was explored by a large open cut, numerous test pits, and a 50-foot-long adit (Moffit, 1914; Pierce, 1946). The polydeformed host rocks of the Haley Creek terrane consist of metasedimentary rocks, including marble, and metaplutonic rocks that range from peridotite to trondhjemite (Winkler and others, 1981 [OFR 80-892-A]). The protolith ages are not known, but much deformation and recrystallization of the Haley Creek terrane probably occurred in the mid-Cretaceous or later.
Geologic map unit (-144.266571707114, 61.3051262961021)
Mineral deposit model Duluth Cu-Ni-PGE? (Cox and Singer, 1986; model 5a)
Mineral deposit model number 5a?
Age of mineralization Not known; the protolith ages of metasedimentary and metaplutonic rocks in the Haley Creek terrane are not known but much deformation and recrystallization probably occurred in the mid-Cretaceous or younger (Winkler and others, 1981 [OFR 80-892-A]).
Alteration of deposit The ultramafic host rocks are extensively altered to various assemblages of antigorite, chlorite, epidote, hornblende, limonite, magnetite, serpentine, tremolite, and talc.

Production and reserves

Workings or exploration This prospect was explored by a large open cut, numerous test pits, and a 50-foot long adit (Moffit, 1914; Pierce, 1946).
Indication of production None
Reserve estimates One mineralized body is 200 feet long, 1 inch to 22 feet thick, and exposed over 150 feet vertically. Another mineralized body is 45 feet long; it is 3 feet thick at the surface, but it pinches down to a 6-inch thickness within 10 feet of the surface (Kingston and Miller, 1945). The resource in these two bodies is 6,500 tons of material that contains 0.22 to 7.61 percent nickel and 0.12 to 1.56 percent copper (Kingston and Miller, 1945, p. 56).

Additional comments

This prospect is in Wrangell-St. Elias National Park.

References