Previously unexplored deposits of copper, nickel, gold and other precious metals in Minnesota, Wisconsin, Michigan, and Ontario are attracting new attention from mining interests and citizens in the Great Lakes region. Although these deposits have long been known to geologists, they were not economically attractive until recently. Increasing global demand for copper, platinum and other metals widely used in renewable energy technology, cell phones, and electronic devices is driving metals prices up, and along with it, investment and exploration by mining companies.
The metals are contained in sulfide ore deposits, hence the use of the term sulfide mining. When rocks containing sulfides are disturbed, broken up, and come in contact with air and water, sulfuric acid is produced. The acid leaches out metals and other chemicals from the rock, forming acid mine drainage, which pollutes water and harms fish and wildlife. Acid mine drainage continues long after mines are no longer productive—for thousands of years in some cases (there are ancient Roman mines that are still polluting).
Citizens in communities across the Great Lakes are watching closely as mining proposals surface and many are voicing their concerns about sulfide mining in our region:
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