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Kiowa Clay Mine, M-2007-009 <br />Response to Adequacy Comments <br />17 April 2007 <br />Page 8 <br />effect. Vegetation on 3:1 slopes of this length is considered stable. Should <br />significant erosion arise over the course of mining, this would be noted in the <br />inspection process and the applicant would take appropriate measures to <br />introduce coir biologs or other level spreaders, mechanical erosion protection, or <br />grading variation to collect water in gentle swales. At this time, such measures <br />are not anticipated given the benched reclamation plan. <br />13. The reclamation plan map depicts a large pit area, approximately 72 <br />affected acres in size that will be graded to a bottom elevation of 6150 <br />feet. Under this plan surface water from runoff and rainfall will accumulate <br />in the pit. Please explain how the water will be removed from both sites <br />during the mining operations and upon reclamation of the site. Under the <br />CDPS Stormwater requirements, if stormwater runoff is intercepted by this <br />operation and is not diverted or captured in priority, it must be released to <br />the stream system within 72 hours. This may require a discharge permit <br />from CDPHE-WQCD. Otherwise, the operator will need to make <br />replacements for evaporation. Please address accordingly. <br />There is no intent to capture water for longer than 72 hours as an effect of the <br />proposed operation. Stormwater will be managed through trenches on the <br />western (downslope) side of the mining area, which will capture water and direct <br />runoff from disturbed area to a detention and water quality feature, as depicted <br />on Revised Exhibit C-3 (Revised Mining Plan). <br />Prior to the mine daylighting at the west (the early mining phases}, a small <br />amount of water may runoff into the pit. Note that negligible off-site flow is <br />captured by the operation, as the eastern face is at the top of a ridgeline; the <br />amount of water captured by the pit in any scenario is basically the only <br />significant amount of water that would need to be collected and subject to water <br />quality measures. <br />During the early mining phases, the operator will maintain a pump at the site for <br />the contingency of rainfall. Operations will cease if and when runoff begins to <br />accumulate in the pit, and the pump will be activated to evacuate the pit and <br />send water to the sediment pond depicted on Revised Exhibit C-3. Given the <br />location of the initial mining footprint, a swale may be used to direct flow overland <br />to the sediment pond once discharged by the pump. <br />The applicant acknowledges and agrees to adhere to all regulations and <br />permitting requirements regarding the collection and discharge of surface waters. <br />14. Please further explain the surface water management plan for the site <br />upon reclamation. As there appears to be no positive drainage flow from <br />