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SubTerra, Inc. Peabody Twentymile Coal LLC 09/27/2014 <br />Foidel Creek Mine <br />Permit Revision for Longwall Mining in the Wolf Creek Seam - Subsidence Evaluation <br />3. Evaluation of Potential Impacts to the Energy Shur <br />This section of the report presents the results of our evaluation of subsidence along Union Pacific's <br />Energy Spur to the Foidel Creek Mine in Routt County, Colorado, due to mining the Wolf Creek Seam <br />in the Northern Mining District, Panels 1 -Right through 9- Right. <br />The layout of the Wolf Creek Seam extractions in the Northern Mining District in relation to the Energy <br />Spur is shown on Drawing 2. Coal from the Foidel Creek Mine will be hauled down track along the <br />Energy Spur across a mined out area in the Eastern Mining District and then across seven of the nine <br />new panels in the Wolf Creek Reserve area. As it crosses the last panel (Panel 7- Right) it also <br />crosses Fish Creek and its AVF. As shown on Drawings 3 and 4, the crossing occurs over the rib - <br />side of Panel 7- Right. There is also an area over 7 -Right where the Energy Spur is located on an <br />embankment immediately above Fish Creek. <br />3.1. Scope of Work <br />The scope of work included evaluating the potential effects of subsidence on the Energy Spur, outline <br />planning for remediation associated with partial re- leveling of the track during undermining, and a <br />preliminary evaluation of the potential effects of rail track remediation on Fish Creek and its AVF. <br />Tasks included: <br />• Estimating the magnitude of subsidence effects on the Energy Spur 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 two <br />locations where the track is located on an embankment immediately above the AVF. <br />12. Approach <br />This phase of remedial planning followed the process used to evaluate impacts from Wadge Seam <br />mining and estimating pre - ballasting requirements previously used to mitigate subsidence impacts <br />prior to undermining of the Energy Spur_ The overall approach included: <br />1. Adding track survey data input to the spreadsheet for the length of track that would be affected. <br />2. Estimating the subsidence for each panel extraction. These estimates are presented in both <br />tabular and graphical form. <br />3. Evaluating whether re- elevation could require fill or ballast placement in Fish Creek or its AVF. <br />Our approach utilized one large, integrated spreadsheet to model maximum and transient subsidence <br />displacements at predetermined locations (or Stations) along the railroad alignment for each of the <br />planned longwall panels. <br />The starting track elevations for Stations were determined from prior baseline surveys and survey data <br />obtained during 12 -Right and 13 -Right undermining of the Energy Spur supplemented by a survey by <br />Twentymile Coal Company. A new survey of the track and ballast area will be performed prior to <br />starting longwall mining. <br />Future work will include estimating track re- leveling requirements in advance of undermining as input <br />to planning remedial work. <br />6 PN: 2013 -26 <br />