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Torch Lake AOC


Stephanie Swart

Torch Lake is an approximately 2,700 acre oligotrophic lake located in the historic copper mining district on the Keweenaw Peninsula in Houghton County. Torch Lake is connected to Lake Superior through Portage Lake by the Keweenaw Waterway's North and South Entry's. The Torch Lake Area of Concern boundary includes Torch Lake and those areas along the western shoreline of Torch Lake where wastes from the production of copper contributed directly to the contaminant loadings of Torch Lake. Torch Lake received approximately 200 million tons of copper ore tailings including stamp sands, water quenched slags, and other process wastes, between the late 1860s and 1968, filling an estimated 20% of the lake's volume and contaminating the lake sediments with copper, other heavy metals, polychlorinated biphenyls, and polycyclic aromatic hydrocarbons.