Questions over whether the state is demanding the highest possible environmental and safety standards in the rebirth of a 1950s-era tailings dam are growing more urgent just as Minnesota’s first proposed copper nickel mine is reaching the final stage of regulatory approval.
Throughout the last decade of environmental review and bitter debate, the $1 billion project by PolyMet Mining Co. has always been anchored to a 2.5-square-mile taconite basin near Hoyt Lakes that would eventually hold hundreds of millions of tons of ore processing waste — perhaps for centuries.
Environmental groups, which have long argued that the design is risky, have now made it a primary focus of their request for a legal review of the project that is now awaiting a decision by state officials.
They cite internal state documents that show that the Department of Natural Resources’ consultants and staff have expressed recurring concerns about the long-term costs and failure risks of the massive earthen structure, and that there could be better options.
Debate over environmental standards also is taking on even greater urgency in the wake of a recent financial filing from PolyMet. In it, company officials told investors that the project’s biggest profits would lie in eventually tripling the size of the mine. And that would triple the amount of the waste.
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