2011-03-14_REVISION - M1977493 (48)

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Permit Amendment (AM-06) - Climax Mine CM0000090 • The peak flow rates from the individual subbasins at Climax are relatively high, due primarily to the steep slopes and high-intensity rainfall associated with the PMP event. Runoff from these basins discharges into the water pools on the three TSFs where the peak flows are attenuated to more manageable levels. The flood storage capacity of the TSF water pools is a primary component of the flood routing system at Climax. The hydrology model results suggest that 2,400 acre-feet of flood storage capacity along with a decant discharge capacity of about 70,000 gpm (156 cfs) would be sufficient to provide adequate PMP flood protection for Tenmile TSF. The model results also suggest that 3,500 acre-feet of flood storage capacity along with a decant discharge capacity of about 180,000 gpm (400 cfs) would be required for Mayflower TSF. For each of the analyses presented herein, it has been assumed that the Clinton Canal would fail during a PMP event. G-8 Water Rights G-8.9 History of Climax Water Rights Climax has appropriated or acquired numerous water rights and constructed a complex network of water diversion, conveyance, and storage facilities to support mineral extraction and production. The majority of the water rights associated with these diversions are located in the Tenmile Creek and upper Eagle River basins, which are tributary to the Colorado River. As mining activities and tailing deposition operations slowly changed the configuration of the process and fresh water systems at Climax, many of the original facilities and water diversion points were demolished or replaced. In response to these changing conditions, Climax filed a blanket water rights application in 1994 for the purpose of obtaining Water Court approval for a simplified and updated water rights decree to cover the Climax water rights in the Tenmile Creek and Eagle River basin. This effort culminated in a decree, informally known as the readjudication decree (case Nos. 92CW233 and 92CW336), which was approved by the Water Court in 2001. The integrated water system approved by the readjudication decree is called the Climax Water Supply System. Thereafter, these water rights have been administered in accordance with the criteria set forth in that decree. The readjudication decree allows flexibility so that water can be diverted at generally any location on the Climax property, upon proper notice to the Colorado Division of Water Resources. Water that fills the reservoirs, TSF water pools, and the underground levels of the existing mine are accounted for as part of the streamflow depletion pursuant to the decree. The terms and conditions of the readjudication decree limit the amount of water that Climax is allowed to deplete from Tenmile Creek and the upper Eagle River each month and each year. The decree also includes detailed information concerning the amount of depletion that can occur under each of the individual water rights. Tenmile Creek depletions are limited to a five-year running average of 5,393 acre-feet per year and a maximum annual depletion of 7,727 acre-feet. No depletions are allowed during the months of November through March, but depletions in the other months are allowed in the following maximum amounts: Month Limit (acre-feet) April 116 May through July (combined) 5,807 August 847 September 538 October 419 Depletions to the upper Eagle River are limited to a five-year running average of 243 acre-feet and a maximum annual depletion of 398 acre-feet. There are no specific monthly limitations for Eagle River depletions. All of the Tenmile Creek and Eagle River water rights are junior to the 1906 hydroelectric water right at the Shoshone Power Plant on the Colorado River, owned by Xcel Energy. Therefore, depletions are further limited to those periods of time when the Shoshone Water Right is satisfied by available river flow at that location. The period of time when Shoshone is satisfied can vary widely from year to year, depending on conditions of river flow. The Climax water rights are sufficient for year-on-year attainment of the five-year Exhibit G G-17 May 2010