2011-03-14_REVISION - M1977493 (57)

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Permit Amendment (AM-06) - Climax Mine CM0000489 of the Tenmile Tunnel. As in Phase I Deposition, the first priority water to be delivered to the mill would be the water decanted from the water pool on Tenmile TSF. Supernatant from the Mayflower TSF water pool would be delivered to Robinson Lake at times when the upstream sources are inadequate to satisfy the mill water demand or when there is storage space available in Robinson Lake. During Phase II Deposition, the SDP will provide first stage treatment of impacted water for use at the mill, with the sludge pumped into the tailing delivery line. However, first stage treatment of other impacted water will take place in the Mayflower TSF water pool. The discharge of circumneutral tailing slurry into the water pool is expected to be consistent with first stage treatment in the facility. Excess water in the Mayflower TSF will be decanted from the water pool and delivered to the new Property Discharge Water 'Treatment Plant (PDWTP). The new PDWTP is anticipated to provide second stage treatment of the impacted waters to comply with stream standards and discharge permit requirements. In conjunction with these operations, potential sources of contamination in the Tenmile Creek watershed include: • Designated chemicals (stored and used) for production of concentrates; ¦ Dust palliatives (stored and used); ¦ Mill water reclaim circuit (including storage tanks and supply system); ¦ Process facility/mine yard (aka: camp) run-off and seepage; ¦ Underground mine and open pit water; ¦ OSF seepage (North 40 and McNulty); ¦ Tailing and process water delivery systems (new TDL and ETDL); ¦ Water treatment chemicals (stored and used) for treatment of mine water (including the Lime Station and SDP); ¦ Robinson TSF; • Tenmile TSF and 3 Dam seepage; and ¦ Mayflower TSF and 5 Dam seepage. 'These potential sources of contamination are also listed in Table T-3 and are shown on Figure AM-06-T- 01. The process water tanks near the mill facilities were demolished and removed in 2006. A new water storage tank is planned as part of the new mill facility. An extensive clear water interceptor system has been established by Climax around the affected areas of the upper Tenmile Creek watershed. The interceptor canal system conveys stormwater around the process facility and TSFs, which limits the amount of impacted waters to be treated and discharged. While these interceptors are not designated EPFs, CIVIC recognizes the importance of these structures to the overall water management system in reducing the quantity of impacted water that must be managed, as more fully described in Exhibit G. The Interceptor System is inspected and maintained as part of routine site monitoring activities. 'The interceptors total approximately 13 miles in length and are labeled as the west interceptor and the east interceptor (Figure AM-06-T-01). These interceptors were constructed in the 1970s during construction of the Mayflower TSF to intercept and convey snowmelt and stormwater around the three TSFs in the Tenmile Creek watershed. The west interceptor begins at the Robinson TSF and drains directly into Tenmile Creek within the Climax property line downstream of the Mayflower TSF. The east interceptor begins at the edge of the McNulty OSF and terminates at the Clinton Gulch Reservoir. The Clinton Canal begins at Clinton Reservoir and terminates at Mayflower Creek. The total Interceptor System handles approximately 14,500 acre-feet of water annually. Clinton Reservoir offers flood protection for Mayflower TSF. T-5.3.2 Environmental Protection Facilities -rhe Climax water management and treatment system, which terminates at the base of 5 Dam, contains E=xhibit T T-17 May 2010