2011-08-08_REVISION - M1977493 (36)

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Unit Hydraulic Conductivity Range (ft/yr) Alluvium 2,595 — 88,378 Glacial Till 22 — 1,238 Paleozoic Sedimentary Bedrock 0 — 596 Tertiary Quartz Monzonite Bedrock 18 — 54 • Water Quality Monitoring Plan Version: R1 EPP — Appendix C Table 3 -1 - Summary of Field Hydraulic Conductivity Tests Climax Molybdenum Company Permit No. M -1977 -493 As shown, the field hydraulic conductivity test data indicate that the alluvium and glacial till in the Tenmile drainage are significantly more permeable than the bedrock units. By comparison, the bedrock units are of relatively low permeability. Therefore, the bedrock units are not capable of transporting significant quantities of groundwater. 3.3.5 Monitoring Sites 3.3.5.1 POC Monitoring Site Climax will use existing well GWM -2 as the POC monitoring well for the Tenmile basin. This well is completed in the Tenmile Creek Alluvium and is considered representative of shallow groundwater downgradient of the tailing facilities that ultimately recharges Tenmile Creek. GWM -2 was constructed in 1987 and its location is illustrated on Figure 4. Historical groundwater quality data for GWM -2 are presented in Appendix A. As illustrated by • the analytical results provided in Appendix A, the water quality at GWM -2 is good with low to non - detectable concentrations of primary constituents. The drillers' and completion log for GWM -2 is included in Appendix B. 3.3.5.2 Internal Monitoring Site Similar to the Eagle River basin, Climax recognizes that, in addition to protecting Tenmile Creek, its water quality monitoring system also needs to monitor for any changes to surface water quality upstream of Clinton Reservoir so that appropriate actions can be taken. In addition to the POC well downgradient of the Mayflower TSF, Climax will monitor two internal surface water locations between mine facilities and Clinton Reservoir. The first new location will be a surface water monitoring site located in upper Clinton Creek between Clinton Reservoir and the Open Pit (Figure 5). The second new location will be a surface water monitoring site in the East Interceptor Ditch between the McNulty Overburden Storage Facility and Clinton Reservoir (Figure 5). These locations were selected so that water quality changes from surface runoff in the vicinity of mine facilities toward Clinton Reservoir will be detected. Data analysis and follow -up actions to be taken by Climax for the internal monitoring sites are described in Section 5 of this Plan. August, 2011 10