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PeabodN <br />Twentymile Coal Company <br />C` <br />January 8, 2008 <br />Mr. Daniel I. Hernandez <br />Senior Environmental Protection Specialist <br />Colorado Division of Minerals and Geology <br />1313 Sherman Street, Room 215 <br />Denver, Colorado 80203 <br />(303) 866-4933 <br />RECEIVED <br />29515 Routt County Road #27 <br />Oak Creek, CO 80467 <br />970.879.3800 <br />.IAN 12008 <br />Division 07 Kaciamation, <br />mining and Safety <br />Re: Twentymile Coal Company - Foidel Creek Mine (Permit No. C-82-056), Minor Revision <br />(MR08-227) - 6MN Temporary Shaft Heaters <br />Dear Mr. Hernandez: <br />Twentymile Coal Company (TCC) requests CDRMS approval of a Minor Revision to our approved <br />Permit for installation, operation, maintenance, and removal of temporary shaft heaters for the 6-Main <br />North (6MN) Intake Ventialtion Shaft. Installation of the temporary shaft heaters is necessary to address <br />severe icing conditions within the shaft that have the potential to interefere with operation of the 6MN <br />Emergency Escape Hoist. Our current plan is to move two portable skid-mounted propane air heaters (15' <br />long, 7' wide, and 7.5' high) onto the existing 6MN Shaft Pad (would be located adjacent to and <br />immediately west of the Escape Shaft Hoist-House (see MR07-218) approximately 50' from the shaft <br />opening), and connect them to a portable propane tank, the existing electrical lines, and to the shaft <br />opening with pre-fabricated vent tubing. <br />In order to address the immediate icing problems, the volume of ventilation air moving down the shaft <br />will be temporarily reduced by adjusting ventilation doors at the shaft bottom, and the remaining air-flow <br />warmed with the portable heaters to thaw the water-ring and associated piping within the shaft collar and <br />liner. TCC will inspect, and may make modifications to the water-ring and piping to reduce future <br />potential for freezing and icing. The temporary heaters will remain in-place until the immediate icing <br />problems are addressed (projected at up to 45 days), then full air flow will be restored to determine if <br />there will be a continuing problem. If problems persist, the temporary heaters could remain in-place for <br />the remainder of the winter (up to 4 months), with the potential that a permanent heater installation would <br />be required (to be permitted separately, if necessary). <br />The 6MN Temporary Shaft Heaters will be constructed entirely within the existing 6MN shaft pad area, <br />will result in no new surface disturbance, and will not affect existing drainage and sediment control <br />structures. At such time as the 6MN Temporary Shaft Heaters are no longer needed to address the <br />immediate shaft icing problems, the portable shaft heaters will be disconnected from the propane tank and <br />electrical connections, the vent tubing will be disconnected, and all system components (ie: portable <br />heater units, vent tubing, and propane tank) will be removed from the site. <br />G:\Environmental\REVISION\MINOR-RV\MR08-227 6MN Temp. Shaft Heaters\MR08-227 18RT Shaft Heater <br />TL.doc