Gunnar Mine

 

The country rocks at this locality are a series of mafic to intermediate lavas, some showing distinct pillow structures, which indicate underwater volcanic eruption. These rocks are intersected by a large dyke-like body of albite granite which is probably an apophysis of an underlying granitic pluton emplaced in the core of an anticline.

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Quartz lenses, veins, and stockworks - rarely exceeding 1m in width, occur in a group of shear zones which cut both the volcanic rocks and the granitic body. Mining was mainly restricted to the veins of one of these zones, which crosses the southern extremity of the felsic dyke. Ore grade mineralization is confined to mafic host rocks, and the productive ore bodies are near the margins of the granitic dyke.

The ore assemblage consists of abundant pyrite, with lesser amounts of sphalerite, pyrrhotite and galena. Gold occurs principally as the native metal, predominatly in quartz. In addition to quartz, the gangue material contains some ferruginous carbonate and subsidiary amounts of calcite, albite, sercite and tourmaline. Minor amounts of fuchsite occur sporadically. The sheared wall rocks show strong chlorite-carbonate pyrite alteration.

The main shaft reached a depth of 625m.

                  Tons Milled              -   298,829 tons

                  Gold Recovered     -   101,463 oz.

                  Silver Recovered   -  na.

                  Average Grade        -  0.34 oz./ton

                  Years Worked          -  1936-42

 

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