2019-06-25_REVISION - C1981035 - Laserfiche WebLink

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GCC GCC Energy, LLC Telephone: 970.385.4528 6473 County Road 120 Energy "Safety as a Value" Facsimile: 970.385.4638 Hesperus, CO 81326 worst-case scenario where steady state flow is achieved within the waste pile. The proposed 5'x4' underdrain size for TR-27 provides 20 [ft3/ft] of trench length which is on the conservative side of the Trautner recommendation. Appendix 11 7. Cover sheets for Appendix 11 documents (SEDCAD runs) appear to be inaccurate. Please revise. Consider including the drainage report as 11(1) [this is current situation] and the SEDCAD runs as 11(2) or 11(3), as appropriate. GCCE June 25, 2019: The revised drainage report(see#12 below)is submitted as Appendix 11(1A) and the SEDCAD runs are now included as Appendix 11(1B). Table of Contents page iii has been revised to depict these changes. 8. In Appendix 11, the treated water SEDCAD run should include the ponds to illustrate that they provide the required capacity (per Rule 4.05.6). GCCE June 25, 2019: The ponds were not included because,based on guidance from Brock Bowles (DRMS), only the SEDCAD runs for the culverts/ditches changed by TR-27 need to be submitted. The total area contributing to the ponds is actually reduced by—6.5ac because the west hillside is now diverted around the yard area by the proposed TR-27 West Clear Water ditch. 9. The treated water design should be for the 10-year and 25-year events (as it is in current Appendix 11). Alternatively, explain why the 100-year event is used. (This is also per Rule 4.05.6.) GCCE June 25, 2019: The 100-year event was used for the treated water because of the way we understood Section 4.09.2(7). The surface runoff routing structures are required to safely pass the 100-year event when routing runoff off of the pile. This may result in some of the culverts being oversized,but the ditch off the pile will be appropriately sized for the larger, 100-year event. 10.The structures in the SEDCAD runs should match the structures on the appropriate maps. For example, Reach 8 on Map King I-007 is not included in the treated water SEDCAD model. GCCE June 25,2019: Reach 8 has been added to the treated water SEDCAD model (revised Appendix 11(1B). 11.There is a SEDCAD model for the west clear water ditch. Please explain why there are no models for other ditches for the post-reclamation conditions. GCCE June 25, 2019: SEDCAD models were only submitted for the ditches and culverts associated with TR-27, as requested in the December 11, 2018 Notice of Incomplete Application letter. Because the treated water SEDCAD model was prepared using the 100-year event, at the maximum fill elevations, the sections of Reach 10 that will remain in the final contoured map will be properly sized for final reclamation.