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AM-02 EPP Adequacy Review 6 14 December 2010 <br />Schwartzwalder Mine File No. M-1977-300 <br />AFA to meet the state ground water domestic water supply standard, but more importantly, to ensure <br />that Ralston Creek meets the drinking water quality criteria defined by the state WQCC. DRMS will <br />not accept any alternative water quality criteria. <br />C) Section 15(a)(iv), page 15-3. The EPP states that "sorption and precipitation processes remove <br />uranium from solution." Have any geochemical studies been conducted to verify that those processes <br />are indeed occurring in the stream and are removing uranium? <br />D) Section 15(b)(iii) Source Removal, page 15-7. The operator proposes accelerated weathering tests. <br />As previously discussed in the review process for TR-14, EPA method 1312 (synthetic precipitation <br />leaching procedure, or SPLP) is more appropriate for this type of characterization than method 1311. <br />However, these tests are only 18 hours in duration and do not provide a complete assessment of long- <br />term leaching behavior. For that reason, the operator must select one sample among the suite to be <br />submitted for SPLP analysis that will also be subjected to a long-term accelerated weathering test. The <br />Division recommends the humidity cell test, ASTM method D 5744-07, and the test must be run for a <br />duration of at least six months. The sample to be submitted shall be subject to prior DRMS approval. <br />The specific sample selected, parameters to be evaluated over the test duration, and the analytical <br />frequency are to be determined in collaboration with DRMS before the testing commences. <br />E) Section 15(b)(iv) Permeable Reactive Barrier (PRB). <br />(1) On page 15-8, the EPP states that ground water flowing through the PRB gate would be <br />stripped of uranium and molybdenum. As the Operator's intent is to utilize the AFA as a capture <br />facility for potential leakage from the mine pool, and as the mine pool contains constituents other <br />than uranium and molybdenum that are elevated to undesirable concentrations and may include a <br />combination of cationic and anionic species, please comment (and provide specification if available) <br />on the ability of the PRB to capture additional constituents that will report to the PRB in the event of <br />mine pool leakage. <br />(2) On page 15-9 the EPP discusses hydraulic conductivity. How will the hydraulic conductivity of <br />the PRB compare to the hydraulic conductivity of the AFA? How will this affect ground water flow <br />and what is the possibility that the hydraulic conductivity of the PRB will be substantially less than <br />that of the AFA such that ground water flow will back up and circumvent the PRB? <br />(3) On page 15-10 the EPP describes a pretreatment zone (PTZ) ahead of the reactive cell that <br />might act as a zone for mineral precipitation. Is it possible to quantify the extent of mineral <br />precipitation that will occur? Will the precipitate be removable during periodic system <br />maintenance? If not removable, to what extent will the precipitate shorten the life of the PRB and <br />interfere with PRB operation? <br />(4) On page 15-10 the EPP describes possible flushing with reagents during system maintenance. <br />Please provide a list of all possible reagents that might be used to flush the PRB during the periodic <br />maintenance.