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As discussed in Section 2.1, Tailings Deposition Sequence, tailings were onlydeposited in the <br />upper impoundment during the use of the AVR detoxification method. No deposition occurred <br />in the upper impoundment during interim detoxification. As such, the upper impoundment <br />samples represent tailings material treated only with the AVR system. Howeve[, the free water <br />pool in the upper impoundment was treated with hydrogen peroxide to lower oyanide levels in <br />the water and this treatment may have had some effect on the tailings materialfr below the free <br />water pool. <br />Freezing conditions during November and December allowed access to the lolver pond beach <br />in mid-December. Sampling of the lower pond beach took place from December 16 through 19. <br />Holes 7 through 13 are located on the lower pond beach. <br />Figure 2.2 shows the locations of Holes 1 through 13. Hole logs are contained lin Appendix A. <br />2.2.1.2 Sample Collection <br />The procedures for sample collection were the same for both the up~er and lower <br />impoundments. Fach sample location was staked prior to sampling, and the Coordinates and <br />elevation of each location were surveyed. The locations were then plotted on t~te as-built liner <br />contour map, and the tailings thickness at each location calculated. To preserve) the integrity of <br />the liner during sampling, a maximum hole depth equating to an elevation fivd feet above the <br />liner cover material was determined for each hole staked. No hole was to penetr$te into this five <br />foot zone. <br />Two holes were drilled at each location. The holes were spaced approximately 'three feet apart <br />so that drilling activity in one hole would not cause caving in the second hole. Samples <br />collected from the first hole were used for geochemical test work samples. Samples collected <br />from the second hole were used for column leaching tests with additional maternal available for <br />geochemical testing, if needed. <br />A three-inch diameter hand auger with an extended auger stem was used for sarttple collection. <br />s <br />