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Peabody Twentymile Coal Company 29515 Routt County Road #27 Oak Creek, CO 80467 970.879.3800 August 28, 2006 Mr. Byron Walker, Environmental Protection Specialist Division of Minerals and Geology 1313 Sherman Street, Room 215 Denver, Colorado 80203 (303) 866-4941 RECEIVED AUG 3 0 2006 DivM,n n9tand S e1y n RE: Foidel Creek Mine (Permit No. C-82-056) -Technical Revision (TR06-57) for Modifications to the 6-Main North Sedimentation Pond Deaz Mr. Walker: With this submittal, Twentymile Coal Company (TCC) is applying for and requests CDMG approval of a Technical Revision (TR06-57) to our existing approved Permit, for modification of the 6-Main North (6MN) Sedimentation Pond to convert the pond from a containment structure to a conventional treatmenUdischazge pond. High spring runoff, due to heavy snowpack this yeaz, resulted in greater flows than anticipated to the pond and the consequent need to pump and truck water from the pond in order to maintain adequate storm runoff storage capacity. Given that the 6MN ventilation shaft is a long-term mining installation, TCC has determined that conversion of the 6MN Sedimentation Pond to a conventional discharging structure is a more practical operational approach. Conversion of the 6MN Sedimentation Pond to a discharging structure will involve excavation and stabilization of a single open-channel spillway and dischazge channel. The open-channel spillway and dischazge channel have been designed as a combination spillway to safely pass design flows for the peak runoff from a 25-yeaz, 24-hour design storm event. The pond modifications will be constructed within existing disturbance areas, so this revision will result in no new surface disturbance. As an existing disturbance area, much of the disturbed area runoff is already captured and controlled by the existing drainage and sediment control system. TCC has also applied to the Colorado Department of Public Health and Environment -Water Quality Control Division (WQCD) for modification of their existing approved CDPS Permit for discharge from the 6NM Sedimentation Pond. This submittal includes revised PAP text, exhibits; and maps, addressing the location, configuration, operation, maintenance, and reclamation of the modified pond features. New and revised PAP materials are identified by the attached Summary ofRevisions/Additions. We would like to proceed with this project as soon as possible to take advantage of favorable weather and ground conditions during the 2006 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.