M&A characterizes several deep aquifer systems to evaluate the feasibility and potential impacts of proposed block-cave operations at an Arizona mine.
Client: Resolution Copper, a member of the Rio Tinto Group- Time frame: 2001–present
- Location: Near Superior, Arizona
M&A is assessing the potential hydrologic impacts of proposed block-caving operations at the Resolution Mine, one of the largest copper resources ever identified in North America. The investigations — which include extensive characterization efforts and long-term monitoring — are designed to support the ongoing prefeasibility study (PFS) and upcoming EIS. As part of PFS activities, dewatering of the existing mine workings began in March 2009. Our extensive monitoring activities provide critical information on the system’s response to dewatering activities, which will play an important role in the EIS process.
As part of our efforts to characterize local and regional hydrogeologic conditions, M&A analyzed available data and designed and initiated a rigorous field exploration program. We designed and constructed wells to depths of up to 2,000 feet in the Apache Leap Tuff aquifer. We also conducted pumping tests at these wells to quantify aquifer parameters for multiple completion intervals.
In addition, M&A evaluated groundwater conditions in the deep ore zone by designing, constructing, and testing exploration wells that were completed within multiple horizons. These wells were advanced to depths of up to 6,700 feet.
To better understand the hydraulic properties of aquifers and aquitards, we initiated long-term tests. We also characterized recharge / discharge relationships, integrating all information into a conceptual hydrogeologic model for the groundwater system. Additional drilling and testing is planned for continued hydrogeologic characterization near proposed mining operations.
M&A instrumented boreholes with fiber optics and vibrating-wire piezometers, which were grouted in the boreholes at depths of up to 4,500 feet, to monitor rock stresses and pore pressures in units overlying the ore zone. We also installed packers to permit the testing and monitoring of multiple water-bearing zones within the ore body.
We used a preliminary flow model to simulate conditions that will occur when groundwater starts draining to the proposed mine workings — in particular, mine inflow rates and water-level declines in the overlying aquifer. M&A also analyzed the impacts of groundwater inflow during proposed shaft-sinking and tunnel-drilling operations.
M&A designed and implemented a comprehensive program for monitoring groundwater levels and water quality. We also supported permitting for required rights-of-way by conducting analyses and preparing submittals.
M&A installed a real-time monitoring network to track water levels during mine dewatering. Data are uploaded via telemetry to a web portal designed and hosted by our HydroGeoMetrics Team and accessed as needed by the client.
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