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<br />1 <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />1-z <br />measures described in this report represent further efforts 6y Homestake to <br />prevent seepage from progressing downstream and to determine remedial measures <br />to reduce the amount of seepage occurring from the pond. <br />The slurry wall cutoff, located downstream from the lower tailings dam as <br />shown Sn Figure 2, was installed to intercept surface flow and ground water <br />seepage originating from the tailings pond. The intercepted seepage 1s to be <br />forced to the surface, collected, and returned by a pump-back system located <br />immediately upstream from the slurry wall. <br />Location of the nine grout holes used in the grouting of the lower tailings <br />dam foundation, are shown in Figure 2. The grouting was an investigative <br />experimental program intended to determine if grouting could significantly <br />reduce seepage beneath the dam, and also to stop as much seepage under the dam <br />as possible. <br />Five new monitoring wells were installed at the toe of the tailings dam and <br />downstream from the slurry wall cutoff to monitor ground water levels and <br />water quality before and after construction. Monitoring of these wells allows <br />assessment of the performance of the remedial construction measures. <br />The design, construction of the remedial measures for the lower tailings dam <br />are described in the following sections of this report. The monitoring wells, <br />the slurry wall cutoff and pump-back system, and dam grouting are discussed <br />separately. 8ecommendations For further monitoring activities are also <br />presented. <br />~~~IaRYl`~7 HL~ <br />