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�COLORADO LEGACY LAND <br /> SCHWARTZWALDER MINE <br /> EXHIBIT G. WATER INFORMATION <br /> This information is presented in Technical Revision 23, Attachment B Schwartzwalder Mine Environmental <br /> Protection Plan (Whetstone Associates Inc.,2016)and Exhibit E of this document,which provides an updated <br /> description of the current environmental monitoring program. Additional information regarding the Black <br /> Forest Mine is discussed below: <br /> Disposal of radionuclide impacted alluvial valley soils in the Black Forest Mine is expected to improve the water <br /> quality in shallow groundwater and Ralston Creek. This is because Ralston Creek is in direct communication <br /> with the shallow alluvial aquifer and the contaminated alluvial soils are the primary source of metals loading <br /> to both surface water and groundwater at the Site(Whetstone Associates Inc.,2016). As described in Technical <br /> Revision #14, the scope of the alluvial valley excavation project is to remove any soils with the potential to <br /> leach uranium to groundwater above 0.03 mg/L(Colorado Groundwater Quality Standard and USEPA Drinking <br /> Water Standard). The Black Forest Mine is a dry mine and therefor is not hydraulically connected to the alluvial <br /> aquifer,bedrock aquifer,or Ralston Creek. This is because underground mining in the Black Forest occurred <br /> at elevations equal to or above 6,604 feet above mean sea level. The original Construction Materials 110 Permit <br /> (M-2001-036) for the Black Forest Mine states that the natural (pre-mining) depth to groundwater in the <br /> adjacent alluvium to was approximately 9 feet below ground surface (6,595 feet above mean sea level). The <br /> current static water level (March 2020) in alluvial groundwater well MW-19 (total depth of 21.6 feet below <br /> ground surface)is approximately 15 feet below ground surface(6,625 feet above mean sea level). The current <br /> static water level (March 2020) in nearby deep bedrock groundwater well MW-18 (total depth of 239.9 feet <br /> below ground surface) is approximately 120 feet below ground surface (6,484 feet above mean sea level). <br /> These wells are part of the quarterly groundwater sampling network discussed in Section E.6. Heads in these <br /> wells are likely depressed due to the sump capture system, Ralston creek bypass pipeline, and the inward <br /> gradient created by dewatering the mine pool(the mine pool is required to be 150 feet below the Steve or 6,452 <br /> feet above mean sea level). Following the alluvial valley reclamation, the heads in the shallow groundwater <br /> wells (e.g. MW-19) are expected to return to natural elevations. The head in MW-18 is expected to remain <br /> depressed,as the deep bedrock well is more indicative of the mine pool elevation. Figure G-1 and Figure G-2 <br /> show a cross section of the Schwartzwalder Mine workings. The Steve Adit elevation (6,602 feet above mean <br /> sea level) is approximately the same as the Black Forest entrance adit(6,604 feet above mean sea level). The <br /> maximum mine pool elevation is 150 feet below the Steve Adit (6,452 feet above mean sea level). Additional <br /> surface water and alluvial groundwater data from 1998 to 2010 are presented and summarized in Sections 11 <br /> and 9 of the Schwartzwalder Mine Environmental Protection Plan(Whetstone Associates Inc.,2016). Removing <br /> soils from the alluvial valley and placing them inside the Former Black Forest Mine will prevent these soils from <br /> potentially leaching uranium to the surrounding waters. <br /> NOVEMBER 2020 37 AMENDMENT 5 <br />