Laserfiche WebLink
SubTerra, Inc. Peabody Twentymile Coal, LLC April 11, 2016 <br />Subsidence Evaluation and Ballast Report for 9 -East Longwall Extraction <br />1. INTRODUCTION <br />This report presents the results of our evaluation of potential subsidence impacts to Union Pacific's <br />Energy Spur to the Foidel Creek Mine in Routt County, Colorado, due to mining in the Wolf Creek <br />seam, Panel 9 -East LW. This will be the first of six longwall panels in the Wolf Creek seam that will <br />undermine the Energy Spur. The location of the mine property and the Wolf Creek seam mine layout <br />are shown on Drawings 1 and 2, respectively. <br />Coal from the Foidel Creek mine has and will continue to be hauled down track along the Energy Spur <br />across mined out areas in the Eastern and Northern Mining Districts in the Wadge seam and across <br />the six panels that will be mined in the Wolf Creek seam. The Wolf Creek seam is located <br />stratigraphically below the mined out Wadge seam and will provide for a nominal 9 -ft mining height. <br />Seven longwall panels were previously mined in the Wadge seam extracting coal from beneath the <br />Energy Spur and subsiding the Energy Spur where it ran across the Northern Mining District. In each <br />of these cases, Twentymile Coal, LLC and SubTerra, Inc. developed a subsidence mitigation <br />program, similar to the program described herein, that was implemented by Union Pacific during the <br />period when their track was being undermined. <br />1.1. Scope of Work <br />The scope of work covered by this report includes evaluating the effects of subsidence on the Energy <br />Spur, planning for remediation associated with partial re -leveling of the track during 9 -East <br />undermining, and a preliminary evaluation of the potential effects of remediation on Fish Creek and its <br />AVF. This work follows on from previous work covering subsidence prediction, planning, and <br />management of remedial activities when 9 -Right to 6 -Right in the Eastern Mining District and 12 -Right <br />through 18 -Right' in the Northern Mining District undermined the Energy Spur track. <br />Tasks included: <br />• Predicting subsidence due to 9 -East undermining of the track. <br />• Estimating the magnitude of subsidence effects on the Energy Spur track. <br />• Estimating the partial re -leveling requirements to maintain the track in a serviceable <br />condition during undermining. The criteria for serviceability were determined from input <br />received from Union Pacific Railroad when developing prior mitigation for the Energy Spur <br />track. <br />• Evaluating whether track re -elevation would require extending culverts that allow Fish <br />Creek to pass beneath the Energy Spur at two locations. <br />• Evaluating whether track re -elevation would require filling in Fish creek's AVF at locations <br />where the track is located on an embankment immediately above the AVF. <br />Subsidence Prediction included extending the predictive model to include the new longwall panels, <br />especially the area including the Energy Spur track. <br />' SubTerra, Inc., 2003. Twentymile Coal, LLC, PR6 Railroad Evaluation Report. Prepared for Twentymile <br />Coal Company, April, 2003. <br />PN: 2016-10 <br />