2011-03-14_REVISION - M1977493 (48)

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Permit Amendment (AM-06) - Climax Mine CM0000084 same water handling facilities that are required during mineral production. Also, the facilities that remain will need to be protected from inundation during extreme storm events such as the probable maximum precipitation (PMP) event (reference Exhibit K- Climate Information). The general arrangement of the closure system configuration is shown on Figure AM-06-G-03 through AM-06-G-07, and a schematic depiction of the system is shown on Figure AM-06-G-11. Upon closure, the isolation of impacted water from fresh water and continued compliance with regulatory discharge standards will be of paramount importance. Whenever possible, the site will be reclaimed in such a manner as to reduce the quantity of water requiring treatment. To accomplish this, parallel systems to convey impacted and freshwater through the system will be necessary. Upon closure, the East Side Channel (ESC) will be developed to extend from the camp area to Tenmile Creek below 5 Dam. The intent of this open channel will be to eventually convey fresh water runoff from the reclaimed areas below the fresh water interceptor system to Tenmile Creek without coming into contact with impacted materials or waters. The proposed East Side Pipeline (ESP) will run parallel to the ESC and will be used to collect and convey impacted waters to the water pool on Mayflower TSF. For the purposes of closure, this water pool will be called Mayflower Pond. Impacted waters from the upper Tenmile basin and upper Eagle River basin will continue to receive first-stage treatment at the SDP. The effluent from the SDP and all other impacted waters will be directed to Mayflower Pond for temporary storage prior to treatment by the PDWTP and eventual discharge to Tenmile Creek. Eventual abandonment of the SDP as the volume of impacted water decreases is a possible scenario. The closure configuration will render several of the former water handling facilities as obsolete in regard to management of process waters by Climax. These obsolete facilities, which include the Mayflower Pump Barge, the Robinson Lake Pump Station, the Reclaim Pipeline, tailing delivery lines, tailing distribution systems, the Tenmile Tunnel, and Supply Canal No. 2, will be demolished and reclaimed. G-5.2 Tenmile TSF and Robinson TSF Closure Upon closure, the Tenmile and Robinson TSFs will be reclaimed. A significant amount of reclamation has • already taken place on the former Robinson TSF and a similar approach is anticipated for Tenmile TSF. Given the geotechnical nature of the saturated tailing that currently resides within these existing water pools, called Robinson Pond and Tenmile-Pond upon closure, it is currently considered to be unlikely that a standing water pool, or wet cover, can be avoided without extensive mechanical earthwork efforts. The water quality of these pools is expected to improve in the post reclamation setting. It is anticipated that these water pools can eventually be considered as fresh water and therefore discharged to Tenmile Creek without additional treatment. In 2005, a spillway system was constructed to allow passive conveyance of storm flows through Robinson Pond. This spillway discharges into the ESC, which at this time, empties into the Tenmile TSF water pool. Upon closure, a similar spillway system will be constructed on Tenmile TSF and the ESC will be extended to Mayflower Pond. When the water quality of Robinson Pond and Tenmile Pond has sufficiently improved, the ESC will be extended to bypass Mayflower Pond and discharge directly into Tenmile Creek below 5 Dam. G-5.3 Robinson Lake and Chalk Mountain Reservoir Closure Without the need for reclaim and makeup water storage, Robinson Lake will no longer be needed to complete the process water circuit. It is currently planned that this reservoir will be reclaimed and will eventually become a fresh water facility. Also, because the domestic water requirement upon closure is certain to be significantly less than during mineral production, the need for Chalk Mountain Reservoir for mine related uses will eventually become obsolete. The long-term fate of these facilities is not currently known. However, it has commonly been considered that upon closure, ownership of these facilities could potentially be transferred or sold to other parties such that their ultimate configurations will depend largely on their planned future uses. G-5.4 Fresh Water Interceptor and Bypass Systems As shown on Figures AM-06-G-03 through AM-06-G-07, significant changes to the fresh water interceptor and bypass facilities within the Tenmile Creek watershed are not expected for the closure scenario. The Tenmile Exhibit G G-11 May 2010