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October 19, 2010 C-1981-019/Colowyo Coal Mine KAG <br />Stock tank PD1 has been constructed along the Prospect Ditch permanent drainage. The pond sits immediately <br />south of the drainage thalwag with the upstream portion of the drainage making a gentle turn diverting flow into <br />the pond. The pond embankment appears to be approximately 8-10 feet in height. A riprap emergency spillway <br />allows for excess flows to leave the pond and enter the lower section of the Prospect ditch on the way to Prospect <br />pond. The operator should increase the ground elevation 3-5 feet in the area shown by the arrow to ensure that the <br />topography controls drainage in this critical area. <br />Repair measures as required by NOV CV-2010-004 in <br />the lower potions of the North Tributary of the East Pit <br />Ditch and the lower portion of the East Pit Ditch are <br />now complete (Abatement step #1). Riprap sizing <br />now appears to be in compliance with the design <br />requirements. The operator used a rock breaker to <br />reduce the size of the over-sized material previously <br />placed to the current size. Average size was measured <br />in numerous locations and was 18-28 inches, as shown <br />at right. <br />Number of Partial Inspection this Fiscal Year: 5 <br />Number of Comt)lete Inspections this Fiscal Year: 1 <br />Page 4 of 8 <br />