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Ms. Tonya Hammond <br />Snowcap Coal Company <br />April 20, 2012 <br />Page 2 <br />3. The US Corp of Engineers recommended that that Coal Canyon drainage, which was <br />previously approved for realignment during the reclamation of Ponds 6 and 10, remain in its <br />current configuration. The drainage is stable in its current position and according to Corp of <br />Engineers personnel realignment for the sake of routing the drainage back to its original <br />contours would not be a justifiable reason for issuing a Corp Permit. The Division concurs <br />with not re- disturbing the current alignment of Coal Canyon and will propose to approve <br />leaving Coal Canyon in its present alignment and configuration. To date there have been no <br />other comments or objections by any other state or federal agencies notified of this proposal. <br />With our proposed decision, the Division will need to update and revise the Findings document <br />with regard to Diversions and Conveyance of Overland Flow and Stream Channel Diversions. <br />To facilitate preparation of the Findings document please check and ensure that the design <br />information for Coal Canyon prepared in 1996 is accurate and reflects the configuration <br />proposed to be left as a permanent post -mine feature. The Coal Canyon Runoff and Drainage <br />Design is contained in Appendix 13 -2 of the PAP. From the design information it shows that <br />the diversion drains a watershed greater than one square mile and has been appropriately <br />designed to pass safely the peak runoff of a 100 -year, 24 -hour event. Please add this <br />description and any other distinguishing features of the Coal Canyon alignment to page 14 -13 <br />where Appendix 13 -2 is referenced. <br />4. For the North Portal Reclamation Ditches SEDCAD demonstration beginning on page 14 -6- <br />118, the curve numbers for the Upland and Reclaimed Areas have been changed from the <br />previously approved curve numbers. Please provide the rationale for the change in curve <br />numbers. <br />5. For the North Portal Reclamation Ditches SEDCAD demonstration SCC provided a Flow <br />Summary sheet. Please also provide the Structure Networking and Structure Summary pages <br />from the SEDCAD printout. <br />If you have questions or need additional information, please contact me. <br />Sincerely, <br />AtIU4 P, /5 ",1 <br />Michael P. Boulay <br />Environmental Protection Specialist <br />C: Denver File <br />