| The Snow Lake Arsenopyrite Stockpile is the legacy of inefficient processing of refractory ore at the Nor-Acme Mine, Snow Lake, Manitoba, Canada. Between 1948 and 1959, 250 000 tonnes of cyanide treated, high sulfide refractory ore concentrate were stored in an uncapped waste rock impoundment for future retreatment. Over 40 years of exposure resulted in the development of a supergene alteration profile in the waste. In 2000, the pile was capped by layers of waste rock, clay and silt to prevent water infiltration and the oxidative release of arsenic. The oxidation front is now located approximately 2.3 m below the original surface of the waste, as the waste is preserved from further oxidation by the waste rock cap.; The refractory sulfide residue contained up to 55% arsenopyrite, 10% pyrrhotite, and 5% pyrite. Gangue minerals include quartz, feldspar, biotite, amphibole and minor calcite.* (Abstract shortened by UMI.); *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Adobe Acrobat. |
