A mined-out pit used to store wastewater and milling leftovers at British Columbia's Mount Polley Mine is expected to fill up in April. The B.C. government just issued a permit allowing treated pit water to be discharged into a nearby lake. (Photo by Monica Lamb-Yorsk/Williams Lake Tribune)

A mined-out pit used to store wastewater and milling leftovers at British Columbia’s Mount Polley Mine is expected to fill up in April. The B.C. government just issued a permit allowing treated pit water to be discharged into a nearby lake. (Photo by Monica Lamb-Yorsk/Williams Lake Tribune)