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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 />7. Conclusions and Recommendations <br />We have completed a preliminary evaluation of potential impacts from subsidence at the Foidel Creek <br />Mine for the initial longwall mining program in the Wolf Creek Seam and have presented conclusions <br />regarding potential impacts, mitigation, overall expected performance, and monitoring. <br />7.1. Union Pacific Railroad Energy Sour <br />Some general conclusions can be drawn from the initial work described in Section 3, including: <br />1. With the exception of the first panel (1- Right), the majority of the movement associated with <br />each longwall will occur over a one month period starting when the face is about 500 -feet from <br />the rail line and ending when the face is about 1,000 -feet past the rail line. This distance is <br />measured parallel to face retreat. <br />2. During pre - ballasting, track differential gradients will generally be maintained below 0,4% <br />between adjacent Stations. Final differential gradients are predicted to be at or below 0.3% <br />following subsidence from each of the planned longwall; panels. <br />3. Both of the two remedial methods outlined in this report have been successfully implemented <br />during undermining of the Energy Spur. There is every reason to conclude that they will <br />continue to be successfully applied to remediating subsidence associated with extraction of <br />the panels in the Wolf Creek Seam. <br />7.2. Fish Creek and Foidel Creek. <br />The evaluation presented in Section 4 predicts that Fish Creek will overflow its high bank(s) with the <br />following impacts to Fish Creek and its floodplain: <br />1. A maximum increase in Fish Creek bottom gradient of 0.022 (2.2 %). <br />2. An increase in the surface area of Fish Creek following coal extraction in Panels 4- Right, <br />5- Right, 6- Right, and 7 -Right of about 50 acres. <br />Impacts to Foidel Creek are expected to be minimal with a predicted increase in the surface area of <br />Foidel Creek following coal extraction in Panel 2 -Right of about 2 acres. <br />It is our understanding that the magnitude of predicted surface water area changes in the Northern <br />Mining District contained in our 1999 and 2002 reports and over the Western Mining district in 2009 <br />were never realized illustrating the conservative nature of these predictions. This is likely due to <br />the dynamic process where differential subsidence displacements are readily accommodated by <br />the natural processes of erosion and deposition that occurs rapidly under the high flow conditions <br />experienced during spring months. <br />7.3. Power Transmission Lines. <br />Several conclusions can be drawn from the preliminary work, described in Section 5, including: <br />1. Structures on the Foidel Creek - Steamboat line are predicted to subside by up to 6 -feet <br />18 P N : 2013 -26 <br />