Water Supply Management Solutions for Rosemont Copper, Southern Arizona

This presentation describes the development of water supply management solutions for Rosemont Copper, a company proposing to develop a copper mine and processing operations on company-owned land and adjacent Federal land in the Santa Rita Mountains of southern Arizona. The proposed mining plan of operations and water management strategy are subject to public input and regulatory requirements as part of an ongoing National Environmental Policy Act (NEPA) process. Rosemont has put forth a plan based on water conservation in processing operations, groundwater recharge to balance groundwater pumping for copper production, and mitigation of potential impacts to nearby well owners due to groundwater pumping. Key water conservation measures as part of copper production include use of dry stack tailings technology, as well as recapture and recycling of mine/mill operations process water. Errol L. Montgomery & Associates assembled a team of technical and legal consultants to work with Rosemont to address the pumping and recharge strategy, including mitigation of pumping impacts on nearby wells. Policy/partnership elements of the Rosemont water management plan include agreements to acquire enough Central Arizona Project (CAP) water to recharge the aquifer with an amount equal to 105% of expected pumping, implementation of the recharge program years in advance of mine operation, recharge in the vicinity of the planned wellfield, and negotiation and implementation of a groundwater monitoring and well protection program for well owners in the vicinity of the planned wellfield. Supporting technical analyses include: groundwater exploration and well design, groundwater modeling of impacts due to groundwater pumping and recharge, geographic information system database development, and hydrologic instrumentation and monitoring programs required for ongoing model calibration and documentation of actual groundwater impacts.