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Whetstone' Associates Technical Memorandum 16) On page 15-1 and in other sections of the EPP, the Operator states that limited source removal of contaminated material will be performed in the alluvium as part of RML termination. In light of the elevated uranium concentrations that have been reported over the last year in alluvial monitoring wells (MW3A, MW6, MW9, and MW12) and in Ralston Creek (SW-BPL, SWFBRG, SW- ARH, and SW-LLHG), DRMS strongly recommends that the Operator scrutinize this plan to ensure that source material removal is as thorough as possible to minimize potential future loadings from the alluvium to ground water and surface water. Detailed plans and schedules must be provided to implement complete source removal and impact mitigation. The limited source removal planned for 2010 was to be performed in conjunction with removing the concrete waste water treatment ponds and terminating the Radioactive Materials License. This limited source removal was not intended to be the final or complete source removal for the site. The Operator is committed to source removal of alluvium and fill material, aimed toward meeting water quality standards and achieving long-term sustainable mitigation. 17) On page I5-3, Operator states that they may "seek higher alternate concentration limits (ACLs) based on human health risk. " Operator is reminded that, under §34-32-116(7) (g) C.R.S., DBMS is required to protect the prevailing hydrologic balance.' In this context, DRMS will evaluate environmental impacts relative to baseline conditions rather than impacts or perceived risk to human health or aquatic life. The Operator believes that protection of human health and the environment should be achieved using quantifiable, risk-driven analysis and decision making. This approach has been widely used for decades by State and Federal regulatory agencies to assess appropriate responses to environmental issues. The protective intent of water quality standards themselves are developed based on concepts of probabilistic risks to human health or aquatic life. 18) On page 15-3, Operator proposes a constructed wetland. Constructed wetlands do not always ensure effective treatment, and long term maintenance is required. Please describe in detail, the composition and construction of the wetland, the proposed loading rates, the expected geochemical attenuation processes, and the expected water quality that will ultimately be discharged from the wetland at the down gradient terminus. Please also provide maintenance and bonding details. A constructed wetland is one of several alternatives that have been considered for long-term sustainable treatment of alluvial groundwater to meet the 0.03 mg/L standard. Recent additional feasibility assessments and consultations with additional experts on a constructed wetlands for alluvial groundwater mitigation at the Schwartzwalder site have indicated that a wetland approach, while still a potential option as a mitigation enhancement to any final reclamation plan, should be downgraded in terms of potential feasibility as a primary mitigation measure. This is mainly because aside from source term removal from alluvial fill, any mitigation method will require maintenance and a constructed wetland could have considerably more re-generation requirements than previously thought if used as a primary mitigation mechanism. In all cases, the selected mitigation method(s) will be bonded appropriately once any requisite engineering and feasibility studies are completed. However, unless such engineering studies are determined to be necessary as part of a selected option, it is not possible to determine the water quality that would be expected to result. The Operator looks forward to working with DRMS to gain approval for any selected 4109C.100731 8