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Peabody <br />Twentymile Coal <br />29515 Routt County Road 27 <br />Oak Creek, CO 80487 <br />970.879.3800 <br />Mr. Jason Musick, Environmental Protection Specialist September 27, 2010 <br />Division of Reclamation, Mining, and Safety <br />1313 Sherman Street, Room 215 <br />Denver, Colorado 80203 <br />(303) 866-3567 X 8134 <br />RE: Twentymile Coal Company - Foidel Creek Mine (Permit No. C-82-056), Minor Revision <br />(MR10-248) - 6MN Thickener Undertlow Pipeline Text Revisions <br />Dear Mr. Musick: <br />Twentymile Coal, LLC (TC) requests CDRMS approval of a Minor Revision to our existing approved <br />Permit for a minor modification of the approved plans for installation of the 6-Right Thickener <br />Underflow Borehole and Pipeline, previously approved as TR09-69. The previous approval reflected <br />boring the pipeline under both the UPRR Railroad Spur and Foidel Creek. Due to engineering and <br />logistical considerations, boring was limited to the underground portion of the pipeline where it crosses <br />under the UPRR Railroad Spur, with the result that the pipeline crossing of Foidel Creek will need to <br />be trenched. The accompanying text revisions reflect this change in plans. In addition, TC has <br />submitted an application for a Temporary Construction Discharge Permit to the CDPBE-WQCD, and <br />has made the appropriate notification to the USACE. <br />The following specific measures to effectively control drainage and sediment from the trenched stream <br />crossing will be implemented under the Temporary Construction Discharge Permit:Drainage, and the <br />trenched crossing will be reclaimed immediately following completion of pipeline installation to <br />reestablish the pre-disturbance stream channel configuration: <br />? Install staked (rebar) straw bales and silt fence approximately 40' downstream of the <br />downstream edge of the crossing disturbance area to intercept any sediment generated during <br />construction <br />? Locate a portable pump, with suction-line in the stream, approximately 40' upstream of the <br />upstream edge of the crossing disturbance area. The pump will be sized to handle the <br />maximum recorded historical flows (3cfs) during the construction period. The pump discharge <br />will be located at least 20' upstream from the previously placed straw bales and silt fence, and <br />will be installed to prevent channel scour (may involve placement of a rock discharge apron, <br />depending on conditions) <br />? Install a staked straw bale dam (staked straw bales at least three bales wide, and as high as <br />necessary to contain flows, with a low-permeability upstream facing material (reinforced tarps <br />or brattice cloth) at the pump inlet location to create a pump suction pool, and limit flows to the <br />construction disturbance area <br />? Initiate pumping to temporarily route any stream flows around the construction disturbance <br />area <br />? After a brief interval to allow the area to dry out, utilize a track-hoe setting on the bank to strip <br />soil material from the construction disturbance area and temporarily place it on the bank