As of December 1, 2016, the Pit’s water level was 5,336.34 feet above sea level. When water levels at one of the monitoring compliance points around the Pit reach the Critical Level of 5,410 feet, pumping and treating of Pit water will begin. Current projections estimate that the Critical Level will be reached around 2023. Full monitoring reports and data are […]

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Berkeley Pit slough

On February 8, 2013 material from the southeast wall of the Berkeley Pit collapsed into the Pit water in what is known as a rotational slump or slough. Such sloughs are relatively common in open pit mines. For example, a similar slough occurred at the Berkeley Pit in 1998. The recent slough was about 550 feet wide and caused an […]

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Do Butte residents need flood insurance?

No. Butte residents don’t need to worry about flood insurance in regard to the Berkeley Pit and connected underground mine workings. The Berkeley Pit and connected tunnels act as a sink that collects groundwater in the area. Water levels in the Berkeley Pit and associated mine shafts are currently 175 to 200 feet below the rim of the Pit. The […]

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The water level at the Berkeley Pit has been recorded every month for more than 23 years. In addition to that monitoring, scientists at the Montana Bureau of Mines and Geology have been sampling and analyzing water from the Berkeley Pit twice a year for its chemical composition and physical properties. In the Berkeley Pit, samples are taken from anywhere […]

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Summary of 2012 (published in March 2013) monitoring data related to the Butte Mine Flooding Consent Decree, which includes the Berkeley Pit and associated workings, from the Montana Bureau of Mines & Geology.    

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