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350 Indiana Street,Suite 500 <br /> TETRA TECH Golden,Colorado 80401 <br /> Tel(303)217-5700 Fax(303)217-5705 <br /> www.tetratech.com <br /> Technical Memorandum <br /> To: Raymond Lazuk From: Daryl Longwell <br /> Environmental Manager-Climax Mine Andrew Harley <br /> Doc Richardson <br /> Keith Thompson <br /> Company: Climax Molybdenum Company a Date: March 22, 2016 <br /> Freeport-McMoRan Company (CMC) <br /> Re: Eagle Park Reservoir Chemical Loading Project#: 114-910345 <br /> and Mixing Analysis <br /> cc: File <br /> Overview <br /> A mass balance mixing model has been developed to evaluate the loading of potential chemical <br /> constituents to Eagle Park Reservoir (EPR) if groundwater quality equaled proposed Numeric <br /> Protection Level (NPL) values to be submitted by Climax to DRMS in a revised Water Quality <br /> Monitoring Plan. The mass balance mixing model was developed using available groundwater <br /> quality and calculated flux values of groundwater flow to the reservoir. The geochemical mixing <br /> model was constructed using PHREEQC, version 3.0.6 (Parkhurst and Appelo, 1999). This <br /> modeling platform is able to process multiple equilibrium and mixing reactions that include the <br /> prediction of final chemical speciation. PHREEQC is capable of performing a variety of aqueous <br /> geochemical calculations, such as speciation,saturation indices, mixing of solutions, mineral and <br /> gas equilibrium, and surface complexation reactions. <br /> Model Development and Inputs <br /> Setting <br /> The attached Figure 1 provides a map of the area that identifies the monitoring locations and <br /> physical features in the vicinity of EPR, including Robinson Lake, the Climax Mine process water <br /> storage facility. The Robinson Lake system is considered an Environmental Protection Facility <br /> (EPF). Operation of this storage system is covered under the Robinson Lake Operating Plan, <br /> approved as part of TR-18, to prevent a release of water from the reservoir which could impact <br /> Eagle Park Reservoir. The Robinson Lake Seepage Pump System (also an EPF) is located in the <br /> primary drainage below Robinson Lake Dam, above EPR. This system, consisting of a concrete <br /> Climax Molybdenum Company Page- 1 - <br />