Laserfiche WebLink
Name of Addressee <br />Page 2 <br />Date <br /> <br />E. SedCad model for Pond 16 as built certification, 10yr 24 hour storm event <br />Sediment Volume Estimate <br />It appears that the pond has the capacity to contain this event. <br />1. Why are spillway dimensions particularly slopes, different in the as <br />built model when compared with the postmining model? <br />2. Why is the bottom width of the spillway different in the as built model <br />when compared with the postmining model? <br />3. Also, why is the crest length different between as built and postmining <br />models? <br />4. The cover page reads Sediment Volume Estimate for 100 yr, 24 Hour <br />Storm . This is incorrect it should read fro 10 year 24 Hour Storm. <br />Please revise and resubmit cover page. <br /> <br />F. SedCad model for Pond 16 as built certification, 100yr 24 hour storm event, <br />Containment Analysis <br />It appears that the pond has the capacity to contain this event. <br /> <br />5. Why are spillway dimensions particularly slopes, different in the as <br />built model when compared with the postmining model? <br />6. Why is the bottom width of the spillway different in the as built model <br />when compared with the postmining model? <br />7. Also, why is the crest length different between as built and postmining <br />model? <br />G. SedCad model for Pond 16 as built certification, 100yr 24 hour storm event, <br />emergency spillway hydraulics <br /> <br />H. Pond As Built revised pages <br />NH indicates that the side slopes are no steeper than 2.9H:1V, however the <br />spillway design indicates that the left side slope is 3.4H:1V. <br /> <br />8. Please correct the revised pages to reflect the steeper slope. <br /> <br />I. Post Mining Drainage Analysis Pond 13 Map 1 Attachement 2.05.3(3)-32 <br />Appears adequate. <br /> <br />Due to the short turnaround time the following were not reviewed and will require <br />an extension to adequately address these items: <br /> <br />J. Revised tailwater ditch design <br />K. Pond 13 erosion protection