BUTTE — The all-important pumping of the toxic water in Butte’s Berkeley Pit is temporarily on hold as Butte mine officials are addressing stability issues on this portion of the pit's north wall.
“The pit will go unpumped essentially for the first time since late 2019 for several months,” Montana Resources VP of Environmental Affairs Mark Thompson said.
In December, Montana Resources, which monitors the pit, noticed some instability in the slope that runs under the ramp leading to the pit's pump station on the north wall of the pit. The ramp is the only access to the pump station.
WATCH: Berkeley Pit pumping halted for months due to north wall stability issues
“If we lose the ramp, we would have lost all the pumps and infrastructure at the pump house down below,” Thompson said.
Last month, crews were able to remove that infrastructure and plan to build a new pump house at this location on the south end of the pit. The process of getting the new pump house online could take a few months.
The mine can pump about five million gallons of water out of the pit each day, and it requires pumping about three million gallons a day to maintain the pit’s water level.
Officials say it would take about four years for the pit water to rise to the critical level where it could get into the groundwater.
Thompson assures the community that a few months of not pumping the water will not raise the water level significantly.
“And then we're going to pump at an increased rate when we get set back up to pull it back down because we really kind of like this water level,” he said.
Montana resources will continue to monitor what is causing the movements on the north wall to try to prevent slope failures.
