BUTTE, Mont. (AP) — Treated water that was contaminated by toxic mining waste is being pumped out of Butte's Berkeley Pit.
The Montana Standard reports that officials last week started pumping out about 3 million gallons a day, which is roughly the daily amount of water entering in the pit.
The water is being temporarily discharged into a tailings pond. Pumping is expected to stop at the end of the month for the rest of the system to get running, after which the discharge will flow into Silver Bow Creek.
The pit began slowly filling up with contaminated groundwater and storm water in 1982 after Atlantic Richfield Co. turned off groundwater pumps of the former copper mine.
The Environmental Protection Agency set 2023 as the target date to begin pumping and treating before the water in the pit reaches a critical level.
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Information from: The Montana Standard, http://www.mtstandard.com