An administrative court has recommended denying a key permit for PolyMet Mining's open-pit copper-nickel project, asserting that its design would risk contaminating too much water.
Administrative Law Judge James E. LaFave wrote in a ruling released on Tuesday that the company's plan to apply bentonite clay to an old taconite tailings basin, and then put waste rock from its hardrock mine on top, would not satisfy the state's rules because it was not a "practical and workable" solution.
As a result, PolyMet's permit to mine should be denied by the Minnesota Department of Natural Resources, LaFave wrote.
"That's an amazing result, and a huge victory," said Paula Maccabee, an attorney with the nonprofit group WaterLegacy, one of several organizations that challenged the tailings basin design.
The ruling is not a final decision — it will be sent to back to DNR, which can accept or reject it. LaFave also wrote that if DNR decides differently and proceeds with the permit, the agency should attach special conditions to manage water seeping through mine tailings.
"We're reviewing the [administrative law judge's] recommendation and evaluating our options at this time," Bruce Richardson, a spokesman for PolyMet and NewRange Copper Nickel, wrote in an email.
PolyMet wants to build a massive, open-pit hardrock mine near Babbitt, Minn., and use the former LTV Steel site in Hoyt Lakes to process the material. Hardrock mining has been controversial in Minnesota because of an increased risk of acid mine drainage, compared to the iron mining that's traditionally dominated the state.
Since proposing its mine, PolyMet, which is owned by the international conglomerate Glencore, formed the NewRange partnership with a subsidiary of the Canadian firm Teck Resources. Teck was developing its own mining project next door.