The state agency said project is within expansions considered by its original 45-year-old review. 6:10 pm, Jun. 30, 2021 × An aerial view looking southeast at Cleveland-Cliffs’ Milepost 7 tailings basin. The area in the foreground is where the expansion would take place. (Clint Austin / 2020 file / caustin@duluthnews.com) Minnesota regulators said Northshore Mining's planned 650-acre tailings basin expansion doesn't require an environmental review and awarded the project a key water permit this week. In a 68-page environmental review of need determination, the Minnesota Department of Natural Resources on Monday said because the project was within the maximum size considered in the 1975-1976 environmental impact statement, or EIS, it prepared with the Minnesota Pollution Control Agency, a new environmental assessment worksheet and supplement to its EIS were not needed.