Dear Forest Service Chief Tidwell and BLM Director Kornze,
We are writing on behalf of dozens of organizations, representing hundreds of thousands of people, regarding the catastrophic failure of the tailings dam at the Mount Polley mine in British Columbia, and the implications for tailings dam design and operational safety at hardrock mines on public lands throughout the United States.
Based on the findings and recommendations of the technical review panel of the Mount Polley tailings dam failure, we urge the Forest Service and BLM to take immediate measures to assess the threat posed by similar tailings dams at existing and proposed mines on public lands in the U.S.
In January, a panel of independent experts released its findings from its investigation of the Mount Polley tailings dam, a modern impoundment that breached on August 2014 and released 25 million cubic meters of tailings into the Fraser River watershed in British Columbia. The panel concluded that the dam failed because of a faulty design that didn’t account for the instability of the glacial till on which it was constructed. The failure was complicated by operational practices including storage of excess water in the facility and over-steepening of dam slopes.
The British Columbia Minister of Mines has called for an immediate investigation of all 123 tailings dams within the province and it executed a search warrant at the corporate and mine offices as well as the engineering firms involved in the tailings dam design and management, including AMEC and Knight Piesold.