AV俱乐部

From 1862 to 1939, intermittent gold mining and milling at Wine Harbour, Guysborough County, Nova Scotia produced a total of 42,726 oz. of Au from 72, 413 tonnes of crushed rock. The gold occurs in a series of quartz veins, typically associated with arsenopyrite, that are hosted by the Goldenville Formation of the Meguma Group. Stamp milling and mercury amalgamation were the primary gold extraction methods. The tailings were slurried directly into surrounding streams and low-lying areas around the shores of Wine Harbour. In July 2005, mine tailings, waters and marine sediment samples were collected throughout the Wine Harbour gold district. Chemical analyses of 10 tailings samples collected on-land show very high concentrations of both As (200 to 200,000 ppm) and Hg (4900 to 320,000 ppb). The distribution of As and Hg in marine sediments confirms that most areas of Wine Harbour have been impacted by historical gold milling activities. Chemical analyses of 233 marine sediment subsamples show a wide range in both As (4 to 1500 ppm) and Hg (5 to 9500 ppb) concentrations. In general, the highest As and Hg values are located close to known stamp mill structures along the shores of Wine Harbour. However, high levels of both As and Hg also occur in the bottom sediments of a small inlet at the western end of the harbour, within the bounds of an active mussel aquaculture operation. Contamination of this latter site is likely related to a mill site(s) that is not shown on the historical maps for this gold district. The investigation is part of an ongoing multidisciplinary project which is assessing the marine and terrestrial environmental impacts of historical gold mining activities throughout Nova Scotia. Results from this study can be used to help assess potential ecosystem and human health risks associated with high levels of As and Hg in Wine Harbour.

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Pages: 165
Supervisors: Michael Parsons