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Geotechnical Stability Exhibit <br />Exhibit 6.5 <br />Augmentation Pond: <br />Wildcat Mining Corporation <br />May Day Idaho Mine Complex — 112d Permit Application <br />Revised August 2011 <br />Geotechnical Stability Exhibit 6.5 <br />The augmentation pond option is the only proposed impoundment for the May Day Idaho Mine <br />Complex (Attachment D -6). There are no geologic hazards associated with this location and <br />based on the results of the soil testing and the shallowness of the bedrock observed in the field, <br />there are no geologic hazards that will affect this functionality of the augmentation pond. <br />• When field access is granted, Wildcat will implement its Augmentation Pond <br />Construction Work Plan (Attachment D -6). A geotechnical and civil engineering work <br />plan of the area for the construction of the augmentation pond foundation and <br />embankment will be conducted. An engineering geologist will perform an evaluation of <br />the site including reviewing existing geologic data and a detailed site reconnaissance to <br />develop a detailed geologic map of the site; <br />• Drill 6 test borings, 10 to 30 feet deep, at the approximate location shown in Figure 6.5 -4. <br />Wildcat's engineer /geologist will log the borings and obtain both relatively undisturbed <br />and bulk samples of the materials encountered. Samples will be inspected to confirm <br />field classifications and select samples for laboratory testing. Selected samples will be <br />transported to a testing laboratory; <br />• Perform laboratory testing on selected samples including moisture content and dry <br />density, strength, classification, grain -size distribution, hydraulic conductivity, and <br />compaction tests; and <br />• Perform engineering and geologic evaluations to develop conclusions and <br />recommendations regarding the following: <br />o Grading, including fill placement and compaction, embankment configuration, <br />keyway depths, subsurface drainage, and allowable cut and fill slopes; and <br />o Impoundment liner evaluations, including suitability of onsite soils, compaction <br />and moisture conditioning requirements, and soil improvement considerations, as <br />necessary. <br />Data obtained from the assessment will be utilized to finalize pond design and construction <br />criteria. In addition engineers will determine the best method and equipment to excavate <br />transport and dispose of the excavated material in addition to determining the best methods to <br />place the liner and to stabilize the cut slopes of the structure. <br />Augmentation pond cut and fill slopes: Embankment slopes will not be steeper than 1 (H) to 1 <br />(V) without DRMS approval and Colorado State Engineer permits. The downstream <br />embankment will be constructed with a 2(H):1(V) out slope and the embankment in slope will be <br />equal to or flatter than 1(H):1(V) as illustrated on Attachment D -5, Figure D -5 -1. <br />Augmentation pond excavated material: Excavated material (11,000 cubic yards) will be stored <br />west of the augmentation pond with a slope of <30 degrees or used in the dam embankment. <br />Page 8of <br />