Waste rock is bedrock that has been mined and transported out of the pit but does not have metal concentrations of economic interest. Tailings are the finely ground residuals that remain after the mill process has removed the valuable metals from the ore. Because the waste could affect surface water and groundwater, the waste facilities must limit those impacts to comply with regulatory standards. During mining, we will place all waste rock and tailings on engineered liners similar to those used by community landfills or industrial solid waste disposal facilities.
During closure, the waste rock will be used to backfill the mine pit. The tailings and any remaining waste rock will be covered and monitored per Michigan’s mining regulations.