The court also ordered regulators to set a fixed term for PolyMet’s permit to mine, which had initially been granted without an end date.
The $1 billion NorthMet project has been met with criticism and resistance from environmental groups who are concerned about its potential impact on nearby water sources.
PolyMet owns 100% of the NorthMet Project, the first large-scale project to be permitted within the Duluth Complex in northeastern Minnesota, one of the world’s major, undeveloped mining regions.
The project comprises 290 million tonnes of proven and probable reserves grading 0.288% copper and 0.083% nickel and marketable reserves of palladium, cobalt, platinum and gold.
It would be Minnesota’s first copper-nickel mine.
Back in February the same Court unanimously ruled in favor of a Clean Air Act permit issued by the Minnesota Pollution Control Agency, overturning an order by the state Court of Appeals that had remanded the permit back to the agency.
Midday Wednesday, Polymet’s stock was down up 1% on the NYSE. The company has a $319 million market capitalization.
(With files from Reuters)
