Montana Public Radio

Berkeley Pit Water Treated And Released Into Silver Bow Creek

Sep 30, 2019

For the first time ever, once-toxic water from the Berkeley Pit, Butte’s abandoned open pit copper mine, is being pumped, treated and discharged into Silver Bow Creek.

Last week, the companies in charge of the Berkeley Pit got the greenlight from the Environmental Protection Agency to release treated Pit water into Silver Bow Creek.

On Monday, Atlantic Richfield and Montana Resources achieved that long awaited milestone, and started sending 6 million gallons of treated water per day into the stream. Ron Halsey, an operations manager with AR, explained the event's significance.

"The combination of Montana Resources pumping water from the Pit, and then us treating it and discharging it, is the proof that we can actually hold the water level steady in the Pit," he said.

Under Superfund, the companies are required to keep the acidic and metal-laden water flooding the Pit from reaching the so-called “critical level," when its toxic contents would enter the alluvial aquifer. Uncontrolled, that’s expected to happen in 2023.

Related: Richest Hill - a podcast about the past, present and future of one of Americas most notorious Superfund sites in Butte, MT.