Wheeler

Mine, Probably inactive

Commodities and mineralogy

Main commodities Ag; Au; Cu
Ore minerals azurite; chalcopyrite; malachite
Gangue minerals limonite; quartz

Geographic location

Quadrangle map, 1:250,000-scale SO
Quadrangle map, 1:63,360-scale D-6
Latitude 64.917
Longitude -164.641
Nearby scientific data Find additional scientific data near this location
Location and accuracy This is a copper mine located on an east-facing marble slope in the headwaters of West Branch Sherrette Creek, at an elevation of about 1,350 feet. The location used by Cobb (1972, MF 445, locality 6) is closer to the upper Benson Creek occurrence (SO125). Cobb (1978, OF 78-181) referred to this site as Wheeler (Sherrette Cr.). This is Asher's (1969, DGGS R18) locality 1.

Geologic setting

Geologic description

The Wheeler mine has received more work than any other similar copper-bearing deposit in the area. The mine was explored by several prospecting pits, a 200-foot-long adit in barren marble, and a 90-foot-deep shaft that did not intersect the adit (Cathcart, 1922). The shaft was sunk on a 8-foot-wide exposure of malachite and encountered 30 feet of copper-bearing silica-rich rock, 5 feet of schist, and barren marble below. The copper-bearing zone conforms with layering in the host rock. Material on the shaft dump consists of seams of limonite and malachite to 3 inches wide and remnants of chalcopyrite. High grade malachite-azurite ore was handpicked and shipped to the Tacoma, Washington smelter in 1917 or 1918 (Wimmler, 1926, in Asher, 1969, DGGS R18). This ore was from the upper 20 feet of the shaft and assayed 0.33 ounces Ag per ton, 35.68 percent Cu, 7.60 percent Fe, and 15.40 percent silica. Another shipment, primarily from the schist zone in the shaft, assayed 1.82 ounces Au per ton, 5.16 ounces Ag per ton, and 17.18 percent Cu (Wimmler, 1926, in Asher, 1969, DGGS R18). A total of 24.5 tons of ore were shipped before 1920 (Cathcart, 1922).
This deposit is one of many occurrences of copper mineralization in silica-rich rocks near the regional contact between marble in a lower Paleozoic metasedimentary assemblage and pelitic schist of possible Cambrian or Precambrian age (Till and others, 1986). This type of copper occurrence is present at several localities in the western Solomon quadrangle (Gamble, 1988) and has similarities to several in the Kougarok area of the northeastern Teller quadrangle. In the Teller quadrangle, the Ward mine (TE071) is an example of this type of copper mineral occurrence. The Ward mine has been described as a zone of silicification in marble above a thrust contact with underlying metapelitic schist (Sainsbury and others, 1969; Sainsbury, 1975, p. 90-94). The silica-rich rocks have been metamorphosed and commonly have a laminar fabric. Copper-bearing minerals, mostly malachite but also including azurite and in places chalcopyrite and possibly bornite, are disseminated in the silica-rich rocks. The minor sulfides tend to be along faint laminae and joints (Sainsbury and others, 1969, p. 22). Malachite and azurite also occur in small veins and veinlets in the silica-rich rocks. The summary characterization of this type of Seward Peninsula mineral deposit by Sainsbury (1975, p. 90-94) contains inconsistencies with some descriptions of these deposits. Their origin is uncertain and other possibilities should be considered. One possiblity is that the silica-rich rocks are quartzites and that there is a stratigraphic control to the Ward deposit and similar occurrences elsewhere on Seward Peininsula. Quartzite at the base of the regional carbonate assemblage is recognized elsewhere in the Kougarok Mountain area (Puchner, 1986, p. 1777).
Geologic map unit (-164.64362612217, 64.9162558631509)
Mineral deposit model Copper-bearing mineralization in silica-rich zones at or near base of marble.
Age of mineralization Unknown; if stratigraphic controls are important then it is probably Paleozoic in age.
Alteration of deposit Silicification (?) and oxidation; the development of silica-rich rocks at or near the the base of Paleozoic marble overlying characterizes this type of copper occurrence.

Production and reserves

Workings or exploration The Wheeler mine has received more work than any other similar copper-bearing deposit in the area. The deposit was explored by several prospecting pits, a 200-foot long adit in barren marble, and a 90-foot-deep shaft that did not intersect the adit (Cathcart, 1922).
Indication of production Yes; small
Production notes High grade malachite-azurite ore was handpicked and shipped to the Tacoma, Washington smelter in 1917 or 1918 (Wimmler, 1926, in Asher, 1969, DGGS R18). This ore was from the upper 20 feet of the shaft and assayed 0.33 ounces Ag per ton, 35.68 percent Cu, 7.60 percent Fe, and 15.40 percent silica. Another shipment, primarily from the schist zone in the shaft, assayed 1.82 ounces Au per ton, 5.16 ounces Ag per ton, and 17.18 percent Cu (Wimmler, 1926, in Asher, 1969, DGGS R18). A total of 24.5 tons of ore were shipped before 1920 (Cathcart, 1922).

References

References

Puchner, C.C., 1987, Geology, alteration, and mineralization of the Kougarok Sn deposit, Seward Peninsula, Alaska; Discussion reply: Economic Geology, v. 82, p. 2201-2204.
Reporters Travis L. Hudson (Applied Geology)
Last report date 8/19/1999