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SubTerra, Inc. Peabody Twentymile Coal, LLC April 11, 2016 <br />Subsidence Mitigation During 9 -East Undermining of the Energy Spur at the Foidel Creek Mine <br />1.2. Approach <br />This phase of remedial planning followed the process used to estimate pre -ballasting requirements for <br />prior undermining of the Energy Spur. The overall approach included: <br />1. Inputting track elevation and coordinate data from a Twentymile Coal, LLC provided survey <br />into the spreadsheet for the incremental length of track that would be affected. <br />2. Comparing prior estimated subsidence with actual subsidence over Panels in the Wadge <br />seam. <br />3. Estimating the subsidence along the section of track and the associated re -leveling <br />requirements. These are presented in both tabular and graphical form. <br />4. Evaluating whether re -elevation would 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 down track from Station 0+00 to Station 35+00 (see Drawing <br />3) were determined from a baseline survey by Twentymile Coal, LLC (see Table 1). <br />1.3. Closure <br />The enclosed and attached work products were prepared for Twentymile Coal, LLC as input to their <br />planning and permitting for development and extraction of the Wolf Creek Seam of the Foidel <br />Creek Mine and for no other purpose. The work was performed under the Terms and Conditions <br />of our Contract with Peabody Twentymile Coal, LLC and in a manner consistent with the level of <br />care and skill ordinarily exercised by other professional consultants in similar circumstances at the <br />time the Services were performed. No other warranty, express or implied is made. <br />2 PN: 2016-10 <br />