The Great Lakes region contains nearly 85 percent of North America's surface freshwater, and more than 20 percent of the world's supply of surface freshwater. Lake Superior alone holds 10 percent of the world's readily available freshwater, and by surface area is the world's largest freshwater lake. This immense lake, however, is facing a major threat of toxic pollution from numerous large-scale mining proposals. In addition to widespread mining and exploration in Ontario, Canada, major mines are being proposed or already active within the Lake Superior watershed in northern Minnesota, northern Wisconsin and the Upper Peninsula of Michigan. This includes the “Duluth Complex” in Minnesota, which stretches from the Canadian border south to Duluth, and which may contain the world's largest untapped copper deposit — an estimated 4 billion tons of copper-nickel ores that may be worth more than $1 trillion.
The primary concern with the current mining proposals in the Lake Superior watershed can be summed up in one word: water. This region is defined by its lakes, rivers, streams and high-quality wetlands. Mining for copper, nickel and other heavy metals is often referred to as “sulfide mining,” because these metals are found bonded to sulfur in sulfide ores. Mining proposals in the region would produce millions of tons of waste rock containing sulfides, which when exposed to air and moisture will generate sulfuric acid that can leach into the surrounding streams, wetlands and lakes. This phenomenon is known as “acid mine drainage,” and is responsible for massive water pollution problems at mine sites throughout the western United States. The Center is working with our allies in the region to help ensure that the Lake Superior watershed remains clean and safe for fish, wildlife and future human generations.
The untapped potential of the Duluth Complex has triggered exploratory drilling for copper, nickel and other heavy metals across northeastern Minnesota. In the past few years, mining companies have applied for many more than 100 permits to conduct exploratory drilling on the Superior National Forest of northeast Minnesota. The state of Minnesota owns the mineral rights of much of this region, and has leased many more than 100,000 acres of state mineral rights for exploration. Any new heavy-metals mines in northeastern Minnesota would be in addition to the many open-pit iron-ore and taconite mines in the region, which have already left behind a legacy of toxic pollution and significant harm to water quality and wild rice endurance.
The first proposed copper mine in Minnesota to have reached the environmental review stage is PolyMet's proposed NorthMet mine, to be located on the Superior National Forest. According to the draft environmental impact statement, this open-pit mine would generate 400 million tons of waste rock over 20 years, directly affect more than 800 acres of high-quality wetlands, and destroy 2 square miles of lynx and wolf habitat. Major environmental concerns triggered critical comments from the Environmental Protection Agency and other agencies and organizations, which resulted in the need for changes to the project and a new environmental impact statement.
The second copper-nickel mine proposal likely to reach the environmental review stage in Minnesota is the proposed Twin Metals mine, located near the Boundary Waters Canoe Area Wilderness. With a potential mining area covering more than 25,000 acres, Twin Metals would be the largest underground mine in Minnesota's history — and in fact one of the largest mines in the world. As stated by its proponent mining company, “It will be a lot like an underground city.”
Gogebic Taconite LLC (GTAC) is a Florida-based mining company aggressively promoting a four-mile-long open-pit iron-ore mine in the Penokee Range in northern Wisconsin. GTAC has already pushed through a new bill to significantly weaken Wisconsin's mining laws, and the company is actively exploring for further mining opportunities in the region. The currently proposed iron-ore mine is planned for the headwaters of Tyler Forks River, which flows into Bad River and then Lake Superior. The wild rice and wetlands ecosystem in the lower reaches of the Bad River near Lake Superior are of global ecological significance, and would likely be polluted by the proposed mine.
In addition to the proposed new mines and mineral exploration in northern Minnesota and Wisconsin, there are two new copper mines in the Upper Peninsula of Michigan that are both located close to Lake Superior. The first is the Eagle copper-nickel mine proposed by Kennecott Minerals, a subsidiary of Rio Tinto, located in the Yellow Dog Plains. The second is Orvana's proposed Copperwood mine, located near the Porcupine Mountains.