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conclusion for the pond embankment stability analysis. 1 Response: Construction specifications for the solution ponds are equivalent to the heap leach facilities. Berm construction specifications were intended to include pond embankment berms and heap leach perimeter berms. Liner placement and secondary recovery layer placement construction specifications were also intended to include both the pad and ponds. Appendix N has been revised to clarify this issue. Regarding slope stability documentation, it has been the industry standard to construct pond berms with 3H:1V internal side slopes and 2H:1V external side slopes. This geometry is readily accepted in every state as a stable structure. Cases requiring further attention and perhaps subsequent modification generally include ponds constructed in exceptionally weak foundations or using weak construction materials and ponds constructed on steep natural terrain. The design engineer for the project, SRK, does have on file stability calculations for ponds constructed under the above exceptions which are similar in configuration to the ponds proposed for the San Luis Project and which have been demonstrated to be stable. Pond stability analyses submitted in letter dated 2/22/89. Section D.7.6 ' added to Exhibit D to incorporate this information into the permit application 4/20/89. 42. Pease specify pond sediment accumulation monitoring, maintenance and disposal measures. Response: No significant sediment accumulation is anticipated based on the San Luis ore characteristics as a sandy ore. BMR will lower the ponds annually for a visual examination of sedir~~ent levels. If sediment levels are in excess of 2.5 feet, there~y eliminating one foot of the provided two feet of freeboard, EMR will remove the pond sediment and dispose of the sediment on inactive areas of the leach pad. I Exhibit D, Section D.7.4.2 revised to include this information 4/20/89. Section 0.7.4.3 Leak Detection System t 43. Please specify the leak detection monitoring schedule, reryorting procedures, and mitigation methods to be employed, should solution be detected. Response: 8MR will monitor the secondary recovery/leak detection systems once each day during the initial month of start up for each phase. After the initial month, the secondary recoveryjleak detection system will be monitored weekly. Results will be reported and mitigation employed in accordance with the following schedule.