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Response to DBMS Comments <br />Environmental Protection Plan, <br />Denison Sunday Mines Group <br />Response PVC liner will be utilized and liner seams will be completed by the <br />manufacturer to provide a complete panel for installation; the seams will <br />be tested in accordance with the manufacturers' QA/QC policy. In <br />particular, destructive tests will be performed to verify that the seam <br />strength requirements of the specifications are met. In addition, thickness, <br />bond seam strength (shear strength), and peel adhesion quality assurance <br />tests will be performed. Copies of the QA/QC documentation will be <br />provided to Denison prior to installation of the PVC liner panel. The ore <br />storage pad specifications are attached and provide additional QA/QC <br />requirements. <br />Comment 6 .41zachmen(X Comment 1. <br />Denison: In the context of questioning whether uranium should be regarded as a <br />toxic forming material due to its presence at low concentrations, the Applicant <br />states "Denison selected the BLM risk management criteria (RMC)(BLM 2004) <br />to be appropriate criteria for the site based on future land use for the mines. " <br />DRMS response: The BLMpublication "Risk Management Criteria for Metals at <br />BLMMining Sites, Technical Note 390 rev., October 2004, " contains no <br />reference information for uranium. If this is the same document to which the <br />Applicant refers, please elaborate on how the information in this document was <br />extrapolated to risk management of uranium at the Denison sites. <br />Response BLM did not develop RMCs for several metals detected at the Sunday <br />Mines Group including uranium. In order to assess the potential toxicity <br />of these metals in development rock and ore, EPA Regional Screening <br />Levels (RSLs) for commercial/ industrial exposure scenario were utilized <br />for the following metals: aluminum, tin, titanium, uranium, and <br />vanadium. This assessment approach is described in Appendix B of the <br />EPP, Section 4.1.3 of the report Environmental Geochemistry Investigation of <br />Rock and Soil Material, Sunday Mines Group. As described in this report, <br />maximum concentrations of these metals did not exceed their respective <br />RSLs, indicating that concentrations of these metals in development rock <br />and ore are not a human health risk via direct contact. <br />Comment 7 Fina1D"SReoor1 Z/ 0 Waler Oualilvffonilorin,PPlan. The compliance limit <br />at the groundwater compliance points is proposed to be the 95'h confidence <br />interval of the mean, as defined by the mean ambient water quality from the <br />subsurface monitoring wells nest samples multiplied by two times the standard <br />deviation of the concentrations. <br />DRMS Comment: How many samples will be collected in order to establish the <br />statistical basis for the plan described? <br />Response The compliance limit will be based on groundwater samples collected <br />from wells WS-1, WS-2, and WS-3 which are located within the Top Rim <br />Sandstone of the Salt Wash Member of the Morrison Formation. This is <br />• <br />Final Sunday Mines RTC_v2.doc