A review estimates that $5.6 million to $13 million would be needed at the closed Formosa Mine.
Besides leaving massive piles of polluted waste rock, the company caused a perpetual flow of highly acidic waters to stream down the mountainside and into the headwater of a creek that feeds the Umpqua River. The mine is about 10 miles south of the town of Riddle.
The so-called “acid mine drainage” carries arsenic, cadmium, copper and zinc. The toxic metals have decimated most life in and around the creek, including a fishery that included fall and spring chinook and coho salmon, an EPA report said.
Read more at the Eugene Register-Guard.