ST. PAUL, Minn. (AP) — The final environmental review for Minnesota's proposed PolyMet copper-nickel mine says wastewater from the project would have to be treated indefinitely to prevent pollution.

The 3,500-page document released Friday also says developers would have to put up money to make sure that all cleanup costs are covered after the mine closes. The exact amount and form of those financial assurances would be determined during the permitting process.

Answering a concern raised by critics, the document also says mine runoff would not reach the Boundary Waters Canoe Area Wilderness or Voyageurs National Park.

The release of the report by the Department of Natural Resources starts a 30-day public comment period. The agency will determine early next year whether the review is adequate. Then the company can start applying for permits.