What is PolyMet proposing?
PolyMet wants to mine copper, nickel and precious metals for 20 years at a site located just north of Hoyt Lakes in the Superior National Forest. The NorthMet Deposit is part of what is known as the Duluth Complex, which stretches from about 150 miles north of Duluth all the way to the Canadian border. PolyMet would build three open pits and blast and drill to get to the ore containing minerals. Ore would be put in rail cars and shipped seven miles west to an old iron ore processing plant — LTV Steel — which closed in 2001. PolyMet is repurposing the facility to process up to 32,000 tons of copper and nickel per day.
How significant are the deposits?
The Duluth Complex is considered one of the biggest copper-nickel deposits in the world. PolyMet’s mine would tap into just a small part of that, with the possibility of expanding later. PolyMet’s goal is to produce 72 million pounds of copper, 15 million pounds of nickel and 106,000 ounces of precious metals annually.
How does this proposal compare to other copper-nickel mines in the U.S.?
PolyMet’s mine would initially be much smaller than many of the open pit copper mines in states like Arizona and Utah. But it’s bigger than two copper-nickel mines in the Midwest.
The Flambeau mine in Wisconsin operated during the ’90s and produced about 362 million pounds of copper over the life of the mine — what PolyMet hopes to produce in just five years of mining. One other Midwestern copper-nickel mine is currently under construction in Michigan’s Upper Peninsula. The Eagle Mine owned by Lundin Mining is being built underground, where mining would take place for eight years. That mine would produce more nickel but less copper than PolyMet.
Haven’t we been hearing about this for years? What’s new?
The first draft environmental impact statement for the project was released in 2009. But the draft was sharply criticized by the U.S. Environmental Protection Agency, which determined that the project would result in unacceptable and long-term water quality impacts.
In 2010, the Minnesota DNR, the U.S. Army Corps of Engineers and the U.S. Forest Service agreed to prepare a draft supplemental EIS that would improve the initial draft. This new version includes a proposed land exchange with the Superior National Forest into the draft, which is required for the project to proceed.
It also includes improvements PolyMet has incorporated into the project, designed to further mitigate environmental impacts. They include a cut-off wall around part of the tailings basin to trap water leaking from the site and water treatment plants that use a technology called “reverse osmosis” to purify water before it’s discharged off-site.
What is the environmental impact statement and what does it determine?
The EIS is a 1,800 page document that analyzes the potential environmental impacts associated with the proposed mining project and examines ways those impacts can be mitigated. The Minnesota DNR, the U.S. Forest Service and U.S. Army Corps of Engineers are jointly leading the study’s development, with input from cooperating agencies, including the U.S. Environmental Protection Agency.
After at least a 45-day comment public period, the agencies will incorporate any changes into a final EIS. Then, each of the lead agencies determines whether the EIS is “adequate.” To be deemed adequate, the Minnesota DNR’s Steve Colvin says the EIS must analyze the correct information, respond to substantive public comments in an appropriate way, and follow the EIS process as defined by law.
For the rest of this article, click here: http://minnesota.publicradio.org/display/web/2013/12/02/environment/copper-mining-faq