Is Montana Resources “mining” the Berkeley Pit water?
Yes. The company is still recovering copper from the water in the Berkeley Pit. Since February 2004, 13 million gallons of water per day have been pumped out of the Berkeley Pit and up to a precipitation plant. The water is collected at a depth of 150 feet from the far west side of the Pit below the viewing stand, and is pumped up and around the south and east walls of the Pit to the precipitation plant northeast of the Pit. The precipitation plant uses a centuries-old technology where the acidic (pH of about 2.5) and copper-rich water flows through piles or “cells” of recycled scrap iron. The process is known as “cementation.” The iron in the cells and the copper in the water trade places through a replacement reaction. The iron-rich water is returned to the Pit, creating the waterfall seen on the north rim near the Horseshoe Bend Plant. The product, containing about 70% copper, is dried through a filter press and then sent to an off-site smelter.
