2024-05-17_REVISION - M1977493 (4)

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G-3.3.1 Figure G-05: Storke, Open Pit, and Mill Facility Areas A. Open Pit It is assumed that the open pit would be allowed to fill with water to a level well below the top of the Mosquito Fault(11,113'), which maintains containment of the impacted water. The water in the pit lake would be impacted and require treatment priorto release to Tenmile Creek. As shown on Figure G-05, it was assumed that the elevation of the water level in the pit lake would be approximately 11,000 feet which results in a water surface area of about 77 acres. An in-pit pump station would be installed and the existing 5-Shaft Pump System would be maintained as a back-up for environmental containment. Impacted water would be conveyed to the East Side Pipeline (ESP). Interceptor channels are shown on the figure. The assumption is made that the water collected in these channels would be impacted. Therefore, the only benefit would be to reduce pumping cost, which may or may not justify the expense of their construction. If it can be determined that these channels could collect non-impacted water,there would be more justification to building this system. B. Storke Area It is assumed that,with improvements to the interceptor channels,the drainage area that reports to the existing Storke Wastewater Pump Station (SWPS)could be reduced from the current 93 acres to about 30 acres. The SWPS would be required to continue operations to convey impacted water from the Arkansas River basin to the water treatment systems in the Tenmile Creek drainage. It is also assumed that the overburden material along Ceresco Ridge within the Arkansas River basin would either be reclaimed in place or hauled into the open pit. C. Mill/Camp Area It is assumed that all of the structures in the Mill/Camp area would be demolished and asphalt paving would be removed. The entire area would be graded to a more natural configuration and then reseeded. Buried utilities and foundations would be left in place as much as possible. It is assumed that surface drainage from this reclaimed area would eventually be clean water. The regrading design would include drainage channels to collect the surface runoff and convey it to the East Side Channel (ESC). It is also assumed that subdrains will be required to collect impacted waterthat is expected to be present,similarto the Storke area. The collection channel and subdrain configurations shown on the figure are conceptual. Impacted water would be conveyed to the East Side Pipeline and clean water would be conveyed to the East Side Channel. D. Arkansas Well It is assumed that the Arkansas Well would continue to be operational to provide fresh water or replacement water to the reclaimed mine site. The system would remain similar to the current configuration. E. Water Conveyance It is expected that there will be impacted and clean water sources throughout the site. This will require separate conveyance down the Tenmile Creek valley. The East Side Pipeline is designated for impacted water. The East Side Channel is designated for clean water. There may be a period during initial reclamation that these functions are reversed. It is assumed that the existing Tailings Delivery Line (TDL)would be used to convey impacted water and the East TDL would be removed. TR-22 in 2012 adjusted the start point for the ESC from what was shown on the original AM-06 G figures. It states that clean water from the Camp area would be diverted to the North 40 clean water system. The ESC above Robinson TSF would then not be needed for clean water. Figure G-05 shows an East Side Channel Camp Extension starting just north of the Gate House. The ESP is too low to feed into the SDP by gravity so the TDL would be used if the SDP remains in Exhibit G G-11 May 2024