Geological setting of gold mineralization in the vicinity of the New Britannia Mine, Snow Lake Manitoba

Abstract

The New Britannia Mine is located in the Flin Flon - Snow Lake greenstone belt portion of the Trans-Hudson Orogen at Snow Lake, Manitoba. Between 1948 and 1958 this lode gold deposit, formerly called the Nor-Acme gold deposit, produced 628 461 ounces of gold from approximately 5.3 M tons grading 0.15 ounces gold/ton. TVX Gold Inc. re-opened the mine in 1995 and is a major gold producer at present. Gold mineralization at the New Britannia Mine is hosted in poly-deformed, mafic to felsic meta-volcanic rocks, which are of early Proterozoic age. There are a number of other gold mineralized occurrences in the vicinity of the New Britannia Mine, the most prominent being the No.3 Zone, the Birch Zone, Boundary Zone and the Bounter Zone. The gold mineralization in the Snow Lake area is associated with arsenopyrite, and an intense alteration including, carbonatization, biotitization and silicification of the host rocks. This al eration and gold mineralization is structurally controlled in early (D$\sb1$/D$\sb2$) ductile shear zones, such as the Birch Zone shear, and later brittle-ductile structures, such as the Howe Sound fault and the shear fracture at No.3 Zone. The brittle-ductile structures form imbricate structures that are spatially and structurally associated with the McLeod Road Thrust. In the vicinity of Snow Lake the large-scale outcrop pattern and structures suggest that the exposed meta-volcanic rocks are an oblique section through the hanging wall or side wall ramp structure of a regional scale thrust sheet.