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May Day and Idaho Mine Complex 112 (d) Permit Application <br />• Augmentation pond foundation: Prior to constructing a 1 acre foot storage augmentation <br />pond, Wildcat Mining Corporation will perform a subsurface geotechnical investigation <br />to determine pond foundation characteristics. Data obtained from the assessment will be <br />utilized to finalize pond construction criteria and to determine (a) the best method and <br />equipment to excavate, transport and dispose the excavated material, and (b) the best <br />methods to line and stabilize the structure cut and fill slopes. <br />• Augmentation pond cut and fill slopes: Embankment slopes will not be steeper than 1.5 <br />(H) to 1 (V) without DRMS approval. The downstream embankment will be constructed <br />with a 3(H):I(V) outslope and the embankment inslope will be equal to or flatter than <br />2(H):1(V). <br />• Augmentation pond excavated material: Excavated material (7000 cubic yards -3,000 <br />storage area and 4,000 yds embankments and upslope cut) will be stored west of the <br />augmentation pond with a slope of 30 degrees. Erosion and sedimentation BMPs will be <br />installed prior to excavating or disposing the material in the designated disposal area. <br />• Idaho Operational Area diversion structure: A V notched diversion structure will be <br />designed to contain approximately 5,000 gallons and designed to release excess flows <br />through the weir. Adjacent to the diversion structure, a small pump house will be <br />constructed to convey water from the diversion structure to the augmentation pond <br />through a 4 inch HDPE pipe. <br />• Chief Operational Area Reclaimed Drainage Channel: <br />o The channel and adjacent disturbed area will be stabilized and reclaimed using <br />BMPs. The drainage channel is designed (Table 6.5 -1) to convey the peak flow <br />from a 100 year 24 hour storm event of 87 cfs. The channel will be a trapezoid <br />configuration built on a 5 percent slope where the bottom width and channel <br />depth will be 2 feet and 3(H):I(V) side slopes. The flow velocity is estimated to <br />be 7.5 feet per second (fps). Prior to construction activities erosion and <br />sedimentation BMPs will be installed which will include straw /silt fences bales <br />(above and below the construction area), a rock check dam down gradient of the <br />structure, the disturbed area will be stabilized by seeding, jute netting and <br />appropriately sized rip rap. <br />• The area disturbed by the construction of the road to the Chief Channel and the <br />Portal will be graded, and seeded. The access road will be graded and an inside <br />road ditch with a 1:1 slope configuration will be constructed with ditch rock <br />check dams placed on a 30 foot spacing leading to the Little Deadwood Gulch <br />drainage. <br />• Approximately 200 cubic yards are required to stabilize the access road and to <br />reclaim the Chief portal access road, the Chief Channel, and Chief Portal. <br />L� <br />May Day Idaho Mine Complex 112(d) Permit Application <br />September 21, 2010 <br />El <br />