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G-3 Reclamation and Closure Water Management <br /> G-3.1 System Overview <br /> The closure scenario occurs after mineral extraction and production at the site have permanently terminated. <br /> The facility configuration described herein has been developed for planning purposes. During this period,the <br /> site will be reclaimed and significant changes to the water handling systems will take place. If possible,select <br /> areas of the site may be reclaimed during the production period. It is expected that certain impacted waters <br /> will continue to require treatment thereby necessitating the operation of many of the same water handling <br /> facilities that are required during mineral production. Also,the facilities that remain will need to be designed <br /> for hydrologic events in accordance with regulatory requirements. The general arrangement of the closure <br /> system configuration is shown on Figure G-04 through G-09, and a schematic depiction of the system is <br /> shown on Figure G-10. <br /> Upon closure, the isolation of impacted water from fresh water and continued compliance with regulatory <br /> discharge standards will be of paramount importance. Whenever possible,the site will be reclaimed in such a <br /> manner as to reduce the quantity of water requiring treatment. To accomplish this,parallel systems to convey <br /> impacted and fresh water through the system will be necessary. <br /> G-3.2 Final Process Water Area <br /> The final process water area after closure and reclamation is estimated to be 1850 acres(2.89 sq-mi). This is <br /> 32 percent of the current process water area. The estimated final process water areas are shown on Figure <br /> G-04. The final area is based on the following assumptions: <br /> a. It is assumed that the open pit basin will remain part of the process water area and the pit lake <br /> will contain impacted water. <br /> b. The final process water area includes an area along the toe of 1 Dam where impacted seepage <br /> is expected to continue. A small area at the toe of Robinson Dam is also included in the final <br /> process water area. <br /> c. A reduced portion of the Storke Camp area is assumed to continue to generate impacted <br /> seepage and runoff indefinitely. <br /> d. The southern portion of Mayflower TSF below the fresh water interceptor system will remain <br /> within the process water area. This area is needed for storage of impacted water before <br /> treatment. <br /> e. The area at the toe of 5 Dam is also assumed to remain within the process water area where <br /> impacted seepage is expected to continue. <br /> As previously impacted areas are reclaimed, non-impacted storm water runoff will be routed appropriately off <br /> site. Assuming all the areas shown on Figure G-04 have been reclaimed and removed from the process <br /> water area, the amount of impacted water at the site will be reduced. It is estimated that the closure water <br /> treatment requirement will average approximately 4,820 acre-feet per year(approximately 3,000 gpm average <br /> annual rate). This is about 52 percent of the current annual treatment requirement at the PDWTP. These <br /> values are based on a simplified water balance of the closure site configuration. <br /> G-3.3 Closure System Description and Assumptions <br /> The following closure configuration assumptions and options have been developed by W. W. Wheeler & <br /> Associates, Inc. (Wheeler) through discussions with Climax Environmental and Engineering and through <br /> experience at the site. Design options for similar projects at Climax and other sites were also used when <br /> applicable. Several of the assumptions and configurations were developed during workshops/meetings with <br /> Wheeler, AECOM, Climax, and FMI. The conceptual site closure configuration is shown on the attached <br /> Figures G-05 through G-09. These options and assumptions may be refined as additional information and <br /> designs are available. A schematic of the Closure water management system is shown on Figure G-10. <br /> Exhibit G G-10 May 2024 <br />