State Water Resources Research Institute Program
Project ID: 2007MT188B
Title: Resource Recovery from Flooded Underground Mine Workings- Butte, Montana
Project type: Research
Start date: 3/01/2007
End date: 1/01/2008
Congressional district: at-large
Focus categories: Agriculture
Keywords: groundwater, mining, irrigation
Principal Investigator: Petritz, Keri
Federal funds: $ 2,400
Non-Federal Matching Funds: $ 0
Abstract: Extensive mining in Butte, Montana has created a system of flooded underground mine workings. The groundwater in the Butte Historic Mining District has excessive concentrations of heavy metals and metalloids due to this past mining activity and the high sulfide mineral content of the area. The US EPA determined that it is technically impracticable to remediate this bedrock aquifer. However, there is still potential for utilizing this water in a beneficial way.
The Belmont Mine is one of several dozen vertical shafts that were constructed to access the underground mine workings. It is located near the Berkeley Pit Lake viewing stand. A past attempt was made at pumping water from the Belmont shaft for irrigation of a nearby park and a football field. However, after several weeks of continuous pumping, the concentrations of arsenic, manganese, iron, and zinc surpassed the proposed irrigation standards, and using this source of irrigation water was abandoned
The idea of using Belmont Mine water for irrigation is now being re-visited through a new research grant to MSE-Technology Applications through EPA and DOE’s Mine Waste Technology Program. The project has three facets: 1) A new pumping test of the Belmont Mine will be performed in July, 2007, up to a maximum of 45 days in duration. The rate of pumping and length of the test will be set to simulate the water needs of a full irrigation season. Major cations and anions, total recoverable metals, dissolved metals, alkalinity, iron and arsenic speciation, pH, specific conductivity, temperature, dissolved oxygen, oxidation-reduction potential, and stable isotopes of water, dissolved sulfate, and dissolved inorganic carbon will be monitored for the duration of the pumping test; 2) Bench scale and field scale experiments will be performed to test different low-cost technologies for treating the Belmont water to meet irrigation requirements. From prior data, it is expected that water treatment will need to focus on arsenic, iron, zinc, and manganese; and 3) MSE will examine the potential for using the Belmont pumping station for heating and/or air conditioning of nearby buildings.
In summary, this project has the potential to turn an aquifer that was deemed technically impracticable into a valuable resource, and affords an opportunity to learn more about the flooded underground mine workings of Butte, especially with regards to chemistry, hydrology, and interconnectivity of the mine workings in the southern portion of the district. If successful, using this water in a beneficial way will positively impact the municipal water supply and reduce the stress on the Big Hole River.
Progress/Completion Report, PDF