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831 - 032.794 <br />November 2012 <br />Spring 2012 Subsidence and Geologic Field Observations <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />of recent longwall mining activity. Subsidence - related tension cracks noted in previous site <br />visits were generally no longer discernable due to healing and sealing. <br />Longwall mining in the South of Divide mining area was initiated on the east end of E -seam <br />Longwall Panel El in December 2008. As of the time of our spring 2012 field visit (May 31 and <br />June 1, 2012), longwall mining was complete on E -seam Longwall Panel El and E2 and <br />approximately two- thirds complete on E -seam Longwall Panel E3. Subsidence related <br />observations at the surface were noted along Traverse K -K' (in the Dry Fork Road between the <br />MDW E3 -36 access road and E3 -40 pad and adjacent to the access road to MDW E3 -32.5 pad) <br />and along Traverse K1 -K1' near the MDW E3 -29 pad access road. Cracks at these locations <br />were somewhat expected primarily because this area was above the active longwall mining <br />activities (i.e., an area of maximum expected dynamic subsidence effects) at the time. Additional <br />details regarding the observed subsidence features can be found in Sections 4.4 and 4.5 <br />(Traverses K -K' and K1 -K1', respectively) of this report. <br />Lastly, a few cracks in MDW pads were also observed throughout the SOD above areas where <br />there has yet to be any mining activities. As discussed in previous subsidence reports, evidence <br />suggests that the observed cracks are the result of differential settlement of portions of these drill <br />pads where fill placement is the greatest. <br />Wright Water Engineers, Inc. Page 2 <br />