The Montana Bureau of Mines & Geology (MBMG) measures the water levels at the Pit and in connected mine shafts and wells each month. To monitor water quality, water samples are collected from the Pit semi-annually at multiple depths as safe access allows.
23 wells and 14 mine shafts supply information about the deep bedrock aquifer. 36 wells provide similar data about the alluvial aquifer, which is much closer to the surface. Each month, scientists manually check and record the water levels in these wells. Twice a year, they collect samples to analyze the water’s chemistry. All of this information helps scientists understand where the water is coming from and how it is moving underground.
Complete MBMG monitoring reports and data can be downloaded from our Monitoring Reports page.
The EPA also evaluates site progress and management through five year reviews. The third five year review for the Butte Mine Flooding Operable Unit (BMFOU), which includes the Berkeley Pit and underground mines, took place in 2011. For more information, or to download the 2011 report, click here.