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Treated water being pumped out of Butte's Berkeley Pit

Posted at 11:30 AM, Oct 02, 2019
and last updated 2019-10-02 13:30:26-04

BUTTE — A historic milestone was reached this week in Butte’s continuing Superfund cleanup journey as the first treated water from the Berkeley Pit was discharged into Silver Bow Creek.

“We’re very excited, this is just a monumental day for us, and ARCO and the city of Butte,” said Mark Thompson of Montana Resources.

This was part of a decree between the EPA, Atlantic Richfield and other agencies requiring the rising contaminated water in the pit located on Montana Resources property be treated and halted from rising.

There was a deadline of 2023 stop the water from rising as it reached the critical level where it could spill over into the city’s groundwater.

“Instead of the pit rising as it has for the past 36 years, it will actually stop rising for the first time,” said Thompson.

Water is taken from the pit and treated to remove toxic materials at a processing plant and in a tailings pond. From there, the water is pumped to a polishing plant where it goes through a final step of cleaning and then is discharged near the confluence of Silver Bow and Blacktail creeks.

Montana Resources finished the project more than three years ahead of deadline, “now it’s our turn to show that we can control the pit,” Thompson said.

Officials say the water looks clean and pure. Pure enough to drink? “It’s clean. It’s drinking-water quality, it’s safe for aquatic life, it’s clean water,” said Thompson.

Up to 10 million gallons of water can be pumped from the pit per day.