Will Copper Pots Destroy Lake Superior?

Adam Minter is a Bloomberg View columnist. He is the author of “Junkyard Planet: Travels in the Billion-Dollar Trash Trade.”
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Would you buy high-end copper-clad cookware for Christmas if you knew that its enduring long-term legacy wouldn't be family happiness, but rather a half-millennium of pollution monitoring at the mine where the metal was extracted? British Columbia-based PolyMet Mining Corp. is betting that you won't care and is pushing forward with a proposal to mine in northern Minnesota that, if approved, will likely prove its case.

The NorthMet project, as it's known, will be located in a scenic area within hiking distance of 1.3 million acres of federally protected wilderness and -- most crucially -- rivers that flow into Lake Superior. The mine will be big -- it's designed to tap into the Duluth Complex, one of the world's largest unexploited nickel and copper deposits -- and it will have significant environmental risks. Specifically, the tailings (leftover rocks) brought to the earth's surface during mining will leach acids when exposed to rain and melting snow. Potentially, that will be a lot of acid: PolyMet plans to mine 32,000 tons of rock per day. Similar so-called sulfide-mining operations in other parts of the U.S. have left expensive, polluting legacies that will last in perpetuity. PolyMet needs to do better, a fact it knows.

Indeed, these days, state and federallaws require miners to reclaim and take responsibility for the afterlife of shuttered mines via active reclamation and financial assurances. So, according to the 2,169-page supplemental draft environmental impact statement on the NorthMet project issued by two federal agencies and one state agency on Dec. 7 (an essential stepping stone in receiving development permits), once the mine shuts after operating for an estimated 20 years, the site would be equipped with pollution monitoring and treatment facilities. To determine the duration of these measures, PolyMet ran computer simulations. The results appear on page ES-11 of the impact statement: "200 years at the Mine Site, and 500 years at the Plant Site."

Forget for a moment the question of how likely it is that PolyMet or its successors will be around in 500 years to make good on this commitment; there is the matter of cost. According to the impact statement, starting in the year after closure and continuing for the next 180 to 480 years, annual costs are estimated to be as much as $6 million a year. How, precisely, will the company ensure that this money is still flowing in the year 2500? Details are unsurprisingly sketchy. The impact statement alludes to "financial assurances," "financial instruments" and the possibility of using surety bonds, irrevocable letters of credit, trust funds, insurance policies and -- supposing all else fails -- cash and cash equivalents. According to one prominent advocate of the mine, more details on these assurances will be provided during the permitting process -- if NorthMet makes it that far.

It shouldn't. NorthMet is only one of several proposals to mine the rich copper-nickel deposits in northern Minnesota. With global demand for copper and other metals increasing (if you are reading this on a screen, you're creating that demand, too), it's only a matter of time before the price of these metals makes mining too attractive to turn down. Federal and state governments should pressure mine developers to do better -- at least, better than PolyMet. In the meantime, PolyMet and the other miners would be well served by developing technologies and mining methods that ensure they won't need to create 500-year "financial instruments" that will serve only to secure the resentment of future generations.

This column does not necessarily reflect the opinion of Bloomberg View's editorial board or Bloomberg LP, its owners and investors.

To contact the author on this story:
Adam Minter at aminter@bloomberg.net