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Brock Bowles <br />Page 7 of 8 <br />December 12, 2014 <br />Rules 4.05.9(3), 4.05.9(8)(a), and 4.05.9(20): None of the proposed sedimentation ponds will have <br />a capacity in excess of 100 acre -feet, an embankment height in excess of 10' in vertical height, or a <br />surface area in excess of 20 acres and therefore were not required to be designed and constructed <br />in accordance with C.R.S. 87 -37 -105. <br />Rules 4.05.9(4), 4.05.9(8)(b), and 4.05.9(21): None of the proposed sedimentation ponds meet the <br />size or other criteria of 30 CFR 77.216(a) and therefore were not required to be designed and <br />constructed in accordance with the requirements of 30 CFR 77.216(a). <br />Rule 4.05.9(5): None of the three proposed sedimentation ponds will impound water for a <br />beneficial use during mining and reclamation operations. WFC has been granted approval for <br />planned consumptive uses of water (dust suppression and indoor and outdoor water use at the <br />mine offices) as described in the approved water augmentation plan in Appendix 2.05.6(3) -1c of <br />the permit application package. <br />Rule 4.05.9(6): The three proposed sedimentation ponds have been designed to be stable during <br />all phases of construction and operation. As noted previously, there is some question about the <br />constructed slopes of Pond NHN -001 that will need to be resolved to ensure that the pond is <br />stable. <br />Rule 4.05.9(7): WFC, in Appendix 2.05.3(4) -1 of the permit application package, addresses the <br />embankment stability requirements of Rule 4.05.9(7) for the three proposed sedimentation ponds. <br />The three ponds will have a minimum factor of safety of at least 1.52. <br />Rule 4.05.9(9): It does not appear that the requirements of Rule 4.05.9(9) have been considered <br />in the designs for the three proposed sedimentation ponds. Please describe the measures that <br />WFC will employ to stabilize the upstream face of the sedimentation pond embankments. <br />Rule 4.05.9(10): All three proposed sedimentation ponds have been designed with adequate <br />freeboard to prevent overtopping by waves or by sudden increases in volume. The height of each <br />embankment is at least one foot above the maximum water elevation in each pond. <br />Rule 4.05.9(11): Division inspection reports to date indicate that routine maintenance of the NHN- <br />001 sedimentation pond embankment has been adequately addressed. <br />Rule 4.05.9(12): NA - None of the three proposed sedimentation pond embankments incorporates <br />a remaining highwall. <br />