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• <br />• <br />7. Field visits since fall 2009 have revealed the healing and sealing capacity of cracks in <br />surficial material (colluvium and alluvium) by weather, mass wasting and infilling in <br />crack areas over time. For example, subsidence cracks along Horse Gulch Road above <br />the west end of Longwall Panel El as observed in spring 2010 had healed to the point that <br />they were no longer visible as of the spring 2011 field visit. Subsidence cracks observed <br />along the Dry Fork Road (Location 3 in this report) are expected to heal and seal in a <br />similar manner as the longwall panel face moves further westward and the dynamic <br />subsidence process comes into equilibrium. <br />831 - 032.793 <br />September 2011 <br />Spring 2011 Subsidence and Geologic Field Observations <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />angle of draw for the E -seam in the SOD and Dry Fork mining areas of 15 °. However, <br />following a review by the Colorado Division of Reclamation Mining and Safety, this <br />analysis was revised and calculations revealed a range between 13.6 and 18.4 °. The <br />revised recommended maximum predicted angle of draw for the E -seam in the SOD and <br />Dry Fork mining areas was therefore increased to 19° as outlined in a February 1, 2011 <br />memorandum (Appendix B). <br />Wright Water Engineers, Inc. Page 46 <br />