The US Environmental Protection Agency has issued an EC-2 environmental concerns rating for PolyMet Mining's NorthMet project, for the supplemental draft of its environmental impact statement.
The NorthMet project is 100%-owned by PolyMet through a long-term lease and is part of north-eastern Minnesota's Duluth Complex, one of the world's largest undeveloped deposits of copper, nickel and other precious metals.
NorthMet ore body features two significant assets and comprises 275 million tonnes of proven and probable reserves, grading at 0.79% copper equivalent with measured and indicated mineral resources of 694 million tonnes, grading at 0.74% copper equivalent.
PolyMet Mining noted that the rating demonstrates the significant improvements the company has made to the project in response to previous public and regulatory comments.
PolyMet Mining president and CEO Jon Cherry said the EPA review provides feedback and guidance to the co-lead agencies for enhancements to finalise the environmental review process.
"We will continue to work with the co-lead agencies to ensure they receive additional data or information that might be required to address the EPA's comments," Cherry said.
The EC rating is one of four possible with the highest, lack of objections, typically reserved for conservation-related projects such as the Upper Mississippi National Wildlife and Fish Refuge comprehensive conservation plan implementation.