ST. PAUL, Minn. (AP) — The Minnesota Supreme Court has agreed to hear a challenge by environmentalists over portions of a lower court ruling involving a key permit for the proposed PolyMet copper-nickel mine.

The Minnesota Court of Appeals in January reversed a 2018 decision by state regulators to issue PolyMet Mining Corp. a water quality permit for the project. It sent the case back to the Minnesota Pollution Control Agency for further proceedings. That was a win for environmentalists, but they’re challenging other parts of the ruling.

The Supreme Court’s order Tuesday is just the latest step in a long legal battle over the project.

By — Lakeland News