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premature." Therefore, TR-28, which addressed long-term water quality in the <br />West Pit, was withdrawn from consideration by DMG at the request of BMRI. <br />With regard to the installation of a slurry wall, BMRI, the DMG, and the CDPHE <br />have reviewed the potential merits of the slurry wall and all parties have <br />concluded that the long-term consequences of the slurry wall outweigh the short- <br />term benefits as perceived by the reviewers. The flushing action provided by the <br />inflow of groundwater from the Rito Seco alluvial aquifer is a fundamental <br />component of the TR-026 water management plan because the inflow of <br />groundwater with lower concentrations of constituents more effectively flushes <br />the secondary sulfate salts associated with the backfill material. When the TR- <br />026 water management program is completed, the water quality in the West Pit <br />will no longer contain elevated concentrations of constituents. Thus, the issue of <br />"keeping clean water clean" is simplistic and will no longer hold. Additionally, <br />the installation of a slurry wall would further disturb the hydrologic system <br />beyond the changes induced as a result of the historical mining activity with no <br />corresponding benefits. <br />The suggestion by the reviewers that BMRI install a reactive barrier/wall is an <br />inadequate technical solution because of the nature of the chemical changes that <br />would have to occur in order to alter the concentrations of the key constituents <br />(i.e., sulfate and manganese). A reduction in the concentration of sulfate (and <br />TDS) can only occur through a chemical transformation that includes: (1) <br />precipitation of a solid phase (e.g., gypsum) or (2) a redox transformation coupled <br />to the precipitation of a solid phase (e.g., elemental sulfur or a metal sulfide). In <br />contrast, manganese removal would require an oxidizing environment ideally <br />coupled with a state of elevated pH. Thus, the ideal chemical state of a reactive <br />barrier for treatment of sulfate is antithetical to the optimum conditions for <br />treatment of manganese. <br />An extensive portion of the reseazch and chazacterization conducted as part of the <br />TR-015 Response Plan, as reported in TR-026, focussed on identifying viable <br />Battle Moun(ain Resources, Inc. HS/ GeoTrans <br />11 July 21.1000 <br />