2013-02-28_REVISION - C1982056 - Laserfiche WebLink

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Peabd Mr. Jason Musick, Environmental Protection Specialist Division of Reclamation, Mining, and Safety 1313 Sherman Street, Room 215 Denver, Colorado 80203 (303) 866 -3567 X 8134 Dear Mr. Musick: Best regards, Twentymile Coal, LLC 1111 ENERGY Jerry M. Nettleton Manager Environmental Affairs Twentymile Coal, LLC RECEIVED FEB 2 8 2013 Division of Reclamation, Mining & Safety 29515 Routt County Road 27 Oak Creek, CO 80467 970.879.3800 December 17, 2012 RE: Twentymile Coal, LLC - Foidel Creek Mine (Permit No. C -82 -056), Technical Revision (TR12 -81) — CRDA Ditch Modification Twentymile Coal, LLC (TC) requests CDRMS approval of a Technical Revision to our existing approved Permit for modification of one of the interim drainage ditches for the permitted Coal Refuse Disposal Area. The existing temporary drainage ditch RDA -4a has several spots where the topography and natural drainage conditions combine to limit effective ditch flows and create ditch maintenance problems. TC proposes to shift the upper portion of the existing ditch upslope to improve drainage flows and increase the area available for the next phase of refuse placement. The proposed ditch modification will slightly decrease the contributing drainage area, result in a minor increase in the overall ditch gradient, and reduce the variations in ditch gradient that are contributing to ditch flow /maintenance concerns. Because drainage area and overall gradient have changed, a revised SedCAD run has been completed, and the ditch design will change slightly. In order to construct the realigned portion of Ditch RDA -4a and prevent loss or contamination of the soil material resource, TC will recover soil and suitable material from the area between the existing and realigned portion of the Ditch and the area where the realigned Ditch will be constructed (maximum distance of approximately 320 feet). The recovered materials will be transported and placed in the existing nearby soil and suitable material stockpiles. Given that these materials were already scheduled to be recovered from the CRDA Expansion footprint, designed stockpile quantities will not change. In order to assure effective drainage flows, the material excavated to construct the realigned portion of the Ditch will be replaced in the corresponding segment of the existing ditch and regraded. Since the proposed Ditch modification will not involve any disturbance beyond that already approved for the CRDA Expansion (TR09 -67), this revision should have no impact on the bond reclamation liability. This submittal includes revised PAP text and maps, addressing the location and configuration of the proposed Ditch modification. New and revised PAP materials are identified by the attached Summary of Revisions /Additions. We would like to proceed with this project as soon as possible, to take advantage of favorable conditions during the remainder of the 2012 construction season. We, therefore, appreciate your consideration, cooperation, and assistance in facilitating timely review and approval of this revision application. After you have opportunity to review the accompanying information, please feel free to contact me with any questions or to discuss submittal materials or related matters.