M&A helps a mining company develop its water resources and implement an unprecedented monitoring program to protect nearby water users.
Client: Augusta Resources / Rosemont Copper Company - Time frame: 2006–present
- Location: Southern Arizona
M&A conducted hydrogeologic investigations to support water supply development and permitting for the proposed Rosemont Mine, located on private and public land 30 miles southeast of Tucson. The client’s goal is to not only minimize water use but also to avoid impacts to nearby groundwater users and surface water resources. To accomplish these goals and provide the documentation for the EIS process, M&A hydrogeologists, groundwater modelers, and water policy experts worked closely with a team of engineers, geochemists, and regulatory and legal experts.
M&A designed and implemented a groundwater exploration program to characterize the local hydrogeologic conditions in the area of the proposed mine. The program entailed drilling, installing, and testing 36 monitoring wells and piezometers. M&A also conducted an exploration program for the area around the mine’s production water wellfield, located on Rosemont properties in the Santa Cruz basin, 14 miles northwest of the proposed mine site.
M&A developed a groundwater flow model to evaluate the impacts of future pit-dewatering operations. The model was used to simulate the geochemistry of the pit lake, identify dewatering requirements, and develop a water balance for the system. It was also used to predict surface water and long-term impacts on local and regional groundwater levels. M&A also developed a second groundwater flow model to evaluate impacts associated with the proposed production wellfield in the Santa Cruz basin.
M&A evaluated potential water supply sources — both on site and in nearby groundwater basins — to identify the most reliable, institutionally viable, and environmentally sound alternative for mine operations.
We also developed and implemented a strategy for replenishing 105 percent of the mine’s projected use by purchasing CAP water for recharge within the Tucson Active Management Area. By the end of 2009, more than 40 percent of the mine’s total projected water use was stored.
M&A established a monitoring program for nearby residential wells. We worked with the client and representatives of a group of about 200 property owners to develop a GIS system, to implement a long-term monitoring program, and to create plans for mitigating drawdown impacts.
M&A addressed regulatory and legal issues related to water rights, permitting, well development, and recharge for the project. In addition, we created a GIS database to manage well, groundwater level, and groundwater quality data.
Using the modeling, characterization, and monitoring information, M&A prepared several hydrogeologic reports and data transmittals in support of the EIS process and the application for an APP
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