Minnesota is a mining state. The iron ore mines of Northern Minnesota built communities and provided good paying jobs during the boom times. Mining has devastated those communities during bad times and damaged the natural environment there with the open pits and disposal of tailings, most famously when Reserve Mining Co. dumped its tailings into Lake Superior.
Minnesota Center for Environmental Advocacy understands mining's place in Minnesota and does not oppose it. However, we do expect all mining, whether for taconite or copper-nickel, to be done through environmentally safe and modern mining techniques that do not leave the state's taxpayers cleaning up a mess.
Overview of Minnesota Mining Issues
Although Minnesota has a long history of iron ore mining, sulfide mining for copper, nickel, and precious metals has never been attempted. With increased demand from China and India, however, prices for these commodities are projected to remain high, and that is making Minnesota’s relatively low-grade sulfide ores economically attractive.
Sulfide mining, unfortunately, poses several significant environmental risks. The most significant one is the threat to water quality. When sulfide ores are exposed to air and water, the result is sulfuric acid, which causes the leaching of potentially toxic heavy metals and the release of sulfates that contribute to the methylation of mercury. Methylmercury is the form that bioaccumulates in fish, and therefore poses a direct threat to human health and other wildlife.
If acid mine drainage and sulfate contamination are not properly controlled at these mines, the damage to fish and wildlife, and ultimately to human health and safety, in the Lake Superior watershed will likely be irreversible. To protect water quality, then, there has to be assurance that the mine operators can and will meet all applicable water quality standards, both during mine operation and indefinitely after mine closure.
Minnesota’s citizens and all those with a stake in the preservation of the Lake Superior watershed do not have that assurance today. The project proposers acknowledge that sulfide mining may pose water quality risks, but they have not yet come up with or committed to the kind of large-scale active water treatment that will likely be required. The industry’s record on water quality is abysmal. Hundreds of hardrock mines in the American West have been abandoned, leaving behind mine pit lakes, waste rock piles, and tailings basins that have contaminated hundreds of miles of rivers and streams. The EPA estimates the total clean-up cost exceeds $50 billion. The hardrock mining industry has been the #1 source of toxic waste in this country ever since the annual Toxics Release Inventory was established.
The environmental risks are not limited to water quality, however. These mines will result in the loss of thousands of acres of protected wetlands, with no adequate wetland restoration and replacement plans yet offered. Many of the contaminants from the ore processing plants will be pumped to tailings basins, with large earthen dams that will require continual monitoring and maintenance to remain stable. These operations require enormous amounts of electrical power to operate, with the only available sources being GHG-emitting coal-fired power plants. And, the mining areas selected are critical habitat for at least one endangered species, the Canada lynx.
The Minnesota sulfide mining project that is nearest to actual operation is the PolyMet NorthMet operation in Hoyt Lakes, Minnesota. PolyMet is proposing 1,728 acre open pit mine with 32,000 tons of ore mined daily. Ninety-nine percent of that ore will be stockpiled as waste rock.
PolyMet, along, with the Minnesota Department of Natural Resources (DNR) and the U.S. Army Corps of Engineers (USACE), have released a supplemental draft environmental impact statement (DEIS). Their original DEIS, earned an EU-3 (Environmentally Unsatisfactory—Inadequate) rating from EPA—the lowest possible rating. You can find and read EPA's and MCEA's comments on Polyment's first draft here. As a result, PolyMet is redoing their proposal.
Watch this video (also available here) by Tom Powers to learn more about the costs and economic benefits of mining: