Geologic descriptionMafic 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. |
| Alteration of deposit |
The ultramafic host rocks are extensively altered to various assemblages of antigorite, chlorite, epidote, hornblende, limonite, magnetite, serpentine, tremolite, and talc. |
