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Mr. Dan Mathews <br />June 13, 2008 <br />Page 5 <br />22. For the Stockpond ST-1 Permanent Impoundment Demonstration, insufficient information was <br />provided regarding the spillway capacity. There was no SEDCAD demonstration provided as <br />referenced in the demonstration. The peak flow from the 25-year, 24-hour storm event, the <br />depth of flow and freeboard with emergency spillway flowing at design depth were not <br />provided. Please provide the SEDCAD run and information listed above. <br />23. Under the capacity discussion, SCC indicates that "since the capacity is under 2 ac. ft. limit, the <br />State Engineer's office does not need the review the permanency request". Please provide your <br />reference for the two acre-feet limit. Based on our discussions with the Office of the State <br />Engineer, the two acre-feet limit only applies to Erosion Control Dams with respect to the <br />location of an outlet at or below the two acre-feet storage volume level. Permits or notification <br />may still be required by the State Engineer for these structures. This structure was legally <br />constructed under DRMS jurisdiction. However, at the time of bond release all impoundments <br />including stockponds that are intended to be retained as permanent postmining features shall <br />comply with the applicable State Engineer rules and regulations. State Engineer and DRMS <br />approval shall be obtained for this structure before bond release can occur. <br />24. An error was noted under the capacity discussion of the Stockpond ST-1 Permanent Pond <br />Demonstration, SCC states that "The Factor of Safety from this analysis shows 1.3". This <br />should read "A safety factor greater than 1.3 was calculated by this analysis." <br />C: Sandy Brown