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Paragraph 4. For QA/QC, Cotter should collect a split periodically (one in ten or thereabouts) <br />for analysis at an independent laboratory. Will the XRF analyses be done at a laboratory or on <br />site using a hand-held unit? <br />Response: <br />Cotter will send sample aliquots to a vendor laboratory for analysis of Ra-226 and uranium for <br />verification purposes as indicated in item No. 5 in TR-14. <br />Any XRF analyses will be done on site using a hand-held unit for screening purposes, <br />recognizing that moisture content and material particle size may be limiting factors in the <br />reliability of such measurements. In general, solid phase source term materials within the <br />alluvial fill are expected to have a clear gamma signature that can be readily measured with <br />gamma detection instruments. <br />The above information has been added to the text of item No. 4 in TR-14. <br />Paragraph 5. EPA Method 1311 is acceptable for this type of analysis, but EPA Method 1312, <br />the synthetic precipitation leaching procedure, is more appropriate for mining-derived material. <br />Response: <br />The referenced analytical method "EPA Method 1311" has been replaced in the text of item No. <br />5 in TR-14 with "EPA Method 1312" and EPA Method 1312 will be used in accordance with <br />this DRMS recommendation. <br />2