The Minnesota DNR today (FRI) is expected to release its environmental study of a copper-nickel mine proposed for Northeastern Minnesota. The valuable minerals occur in a sulfide deposit, and sulfide mining elsewhere in the world has damaged water systems as the waste rock produces sulfuric acid. Betsy Daub (DAWB) is with the group Friends of the Boundary Waters Wilderness. She says it's unlikely the proposed Polymet mine would be any different.