Laserfiche WebLink
SNOWCAP COAL COMPANY <br />POND NO. 11 -CAMEO BORROW AREA NO. 2 <br />CERTIFICATION STATEMENT <br />Sediment Pond 11 was first certified by, Larry M. Reschke, P.E., on July 21, 1994. Mr. <br />Reschke's certification statement noted the pond was constructed during June and July <br />1994. The pond was constructed with an open channel emergency spillway that was <br />designed to flow into Coal Canyon. Dewatering would be by pumping. <br />This pond was changed substantially during borrow operations at CBA-2 during the first <br />quarter of 2002. The embankment on the west end of the pond was opened up to the <br />borrow area. Therefore, the capacity of the pond was expanded to beyond what is <br />necessary for the design event from CBA-2. <br />A September 21, 2005 storm generated peak flows in the Coal Gulch watershed that <br />exceeded those associated with the 10 year event. The Coal Gulch channel overtopped <br />and filled the sediment pond with water and debris. The water and debris flowed into the <br />pond through its open channel emergency spillway. <br />As a result of this problem with the pond, the Operator obtained approval from the DMG, <br />(TR-47), to amend the design of the pond so it relies primarily on storage to control run-off <br />from the design event (DMG Rule 4.05.9(2)(e)). Therefore, the open channel primary <br />spillway was no longer required and it could be backfilled. The design event the pond <br />must contain is the 25-year event which generates 0.47 A-F of sediment and 0.66 A-F of <br />run-off for a total required pond capacity of 1.13 A-F. The estimated capacity of the pond <br />is 5.7 A-F so the pond is significantly oversized for both sediment and water capacity. <br />The primary spillway was backfilled during late October 2005. My final inspection of the <br />pond occurred on December 13, 2005. To the best of my knowledge and belief, the <br />spillway was backfilled as designed and in accordance with the approved plan and <br />applicable regulations. Additionally, to the best of my knowledge and belief, the <br />impoundment has been maintained as designed and in accordance with the approved <br />plan and applicable regulations. ®~4 ~s=°~_ <br />James E.$to;i~r9v %~; ~;<~ ' <br />Colorado Prof i~nal Engineer <br />Registration No _ 0 .<< <br />