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• <br />Water Quality Monitoring Plan Climax Molybdenum Company <br />Version: R1 Permit No. M -1977 -493 <br />Groundwater analytical data from the EVMW are available from quarterly sampling events <br />starting in 1997. The water quality data are presented in Appendix A. As shown, the water <br />quality data from the EVMW show low to non - detectable concentrations of primary constituents <br />with the exception of manganese, iron, molybdenum, TDS and sulfate. Overall these five <br />constituents have downward trends over the sampling period and exhibit variability related to <br />seasonal groundwater elevation fluctuations. <br />In addition to EVMW, Climax will investigate the geology and groundwater conditions in the area <br />between the north abutment of 1 Dam and Eagle Park Reservoir. This information will be used <br />to identify potential locations of one or more groundwater monitoring wells in the area between <br />the north abutment of 1 Dam and the Eagle Park Reservoir. The new monitoring locations will <br />provide water quality data that may indicate potential changes in groundwater quality due to <br />seepage from the Robinson and Tenmile TSFs that could potentially reach Eagle Park <br />Reservoir. <br />For illustrative purposes a location for this new well, identified as EVMW -2, is presented on <br />Figure 3; however the final location will be determined through site reconnaissance and other <br />investigation. Available information indicates that there is a bedrock ridge underlying shallow <br />alluvium /colluviums that trends north -south from Sheep Mountain towards Robinson Lake that <br />separates the northwest portion of Robinson Tailing Storage Facility from Eagle Park Reservoir. <br />Depending on water table depth, the new well will be completed in the saturated <br />alluvium /colluviums and /or shallow bedrock so that seepage through or around the north <br />abutment area of 1 Dam can be detected. <br />Additional monitoring locations at surface seeps /springs upgradient and to the east - southeast of <br />Eagle Park Reservoir will also be investigated and established based on the results of site <br />reconnaissance and investigation (Figure 3). These surface water features represent shallow <br />groundwater in this vicinity and also will be used to detect potential water quality changes. The <br />exact number and locations of the seep /spring monitoring sites will be established during 2011, <br />when snow melt in this area has ended. <br />Data analysis and follow -up actions to be taken by Climax for the internal monitoring sites are <br />described in Section 5 of this Plan. <br />3.3 Tenmile Creek Watershed <br />The open pit mine, mill facilities, Overburden Storage Facilities (OSFs), and the Robinson, <br />Tenmile and Mayflower TSFs are all located within the Tenmile Creek Watershed, west of the <br />Continental Divide (Figure 1). <br />3.3.1 Existing and Potential Future Uses of Groundwater <br />Groundwater in the Tenmile Creek Valley within the Climax Mine property boundary occurs <br />primarily in the areas downstream of the tailings storage facility. Within these areas, current and <br />future domestic and agricultural development of groundwater would not be likely given the site <br />location and climate conditions. Climax does use a bedrock well in the McNulty area in the <br />upper portion of the Tenmile drainage that provides a limited yield that is combined with surface <br />water sources for industrial makeup water and supply to a small potable water treatment system <br />at the Sludge Densification Plant (SDP) located on the east side of Tenmile Tailing Storage <br />Facility. With the exception of this well, the current and future groundwater use at the site is <br />limited to recharge of Tenmile Creek that occurs in the lower portion of the drainage below the <br />tailing storage facilities. <br />EPP — Appendix C <br />August, 2011 8 <br />