ST. PAUL — The Minnesota Department of Natural Resources has denied requests to reconsider the tailings dam permits that it issued for the planned PolyMet copper-nickel mine.

The DNR said Wednesday that opponents did not raise any new issues that materially affect its 2008 decision granting the permits.

The Fond du Lac Band of Chippewa and environmental groups asked the DNR to reconsider in light of tailings dam failures elsewhere.

DNR Commissioner Sarah Strommen said in a statement that her agency studied the failures but remains confident in the safety of the PolyMet dam.