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Mineral Extraction
Published in Earle A. Ripley, E. Robert Redmann, Adèle A. Crowder, Tara C. Ariano, Catherine A. Corrigan, Robert J. Farmer, L. Moira Jackson, Environmental Effects of Mining, 2018
A. Ripley Earle, Robert E. Redmann, Adèle A. Crowder, Tara C. Ariano, Catherine A. Corrigan, Robert J. Farmer, Earle A. Ripley, E. Robert Redmann, Adèle A. Crowder, Tara C. Ariano, Catherine A. Corrigan, Robert J. Farmer, L. Moira Jackson
Placer mining in Canada dates back to the mining of copper by native peoples (Gilbert 1989). The discovery of gold in the Yukon in the late nineteenth century led to the Klondike gold rush of 1898, during which placer mining methods were used to recover considerable quantities of the precious metal, reaching a peak of more than 30,000 kg in 1900. Since then, as primarily manual extraction methods gave way to giant dredges, decreasing demand led to a decline in production to less than 200 kg by 1972 (LeBarge and Morison 1990). The number of dredging operations decreased from 13 in 1917 to a few by the early 1970s. More recently, a strengthening market has prompted a rise in production to over 5,000 kg in 1989 (Van Kalsbeek et al. 1991), while the number of operations rose to 90 in 1979 and to well over 200 in 1989 (Gilbert 1989; LeBarge and Morison 1990). In recent years, production has been from 82 streams, with 16 of them accounting for 84% of the total.
An integrated approach to lithological and structural mapping
Published in Applied Earth Science, 2019
SRK ES applied this integrated approach to a 2-month mapping project in the Klondike Gold District of Canada. Bedrock mineral exploration within the region had traditionally focussed on orogenic gold-bearing quartz veins, which were interpreted to be the source for the world-class placer gold deposits made famous in the Klondike Gold Rush. However, the recent discovery of gold within a unit of felsic schist led to a new model for mineralisation that included an understanding of host rock rheology and composition. The mapping project aimed to provide a refined structural framework and subdivide the complex schist units that were previously classified as ‘undifferentiated’.