Unnamed (south of Dora Lake)

Occurrence, Undetermined

Commodities and mineralogy

Main commodities Ag; Au; Pb; Zn
Ore minerals galena; pyrite

Geographic location

Quadrangle map, 1:250,000-scale CR
Quadrangle map, 1:63,360-scale A-1
Latitude 55.15524
Longitude -132.25036
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is in a borrow pit about 0.4 mile west-southwest of the southern tip of Dora Lake; it is about 0.6 mile northeast of the center of section 35, T. 77 S., R. 87 E.

Geologic setting

Geologic description

In a borrow pit at this site, Maas and others (1991) identified mineralization similar to that at the Lucky Boy Mine (CR174), about 0.5 mile to the east. The pit exposes calcareous metasedimentary rocks and greenstone that contain stratiform quartz-calcite-sulfide veins and stringers. On older maps, these rocks were considered to be part of the Wales Group of Late Proterozoic and Cambrian age (Eberlein and others, 1983; Brew, 1996). More recent mapping, however, indicates that they are previously unrecognized Silurian and Ordovician metamorphic rocks that are less deformed than those of the Wales Group (S.M. Karl, oral communication, 2003).
The prospect also includes a breccia zone about 5 feet thick that consists of rock fragments cemented by quartz and calcite with pyrite, sphalerite, and galena (Maas and others, 1991). A representative sample across the breccia contained 1,065 parts per billion (ppb) gold and 4,311 parts per million (ppm) zinc. A selected sample of sulfide-rich rock contained 6,797 ppb gold, 23.5 ppm silver, 3,210 ppm lead, and 8.87 percent zinc.
Geologic map unit (-132.252023871408, 55.1548857104406)
Mineral deposit model Breccia zone with sulfides; possible massive-sulfide-type mineralization in the host rocks.
Age of mineralization The stratiform sulfide-bearing veins may represent Silurian or Ordovician massive-sulfide-type mineralization. The sulfide-bearing breccia is epigenetic and younger.

Production and reserves

Workings or exploration Only surface sampling in a borrow pit.
Indication of production None

References