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Spring 2014 Subsid ance and Geologic Field Observations <br />South of Divide a id Dry Fork Mining Areas (E -Seam) <br />revised and calculations reveal d a range between 13.6 and 18.4 °. The revised <br />recommended maximum predicted angle of draw for the E -seam in the SOD and Dry Fork <br />mining areas was therefore increa$ed to 190 as outlined in a February 1, 2011 memorandum <br />(see Appendix B of this report). <br />7. Field visits have revealed the he4ling and sealing capacity of cracks in surficial material <br />(colluvium and alluvium) by weathering, mass wasting and crack infilling over time. This <br />is particularly true in colluvium and alluvium which cover much of the surface of the SOD <br />and Dry Fork mining areas, where these effects cause softening and rounding of the crack <br />edges as well as reduction of crack continuity and depth to a point of imperception within <br />a year or two. <br />8. Mining activities within the SOD and Dry Fork mining areas have caused no reported <br />impacts on surface flow or inflows to the underground mine workings even while mining <br />directly beneath Dry Fork. Of similar significance is the lack of observed cracks in alluvial <br />materials within the various mining areas during the past nineteen years of field <br />observations. <br />9. Subsidence - related effects were I observed during the spring 2014 field visit at several <br />locations including the eastern end of Traverse C -C', along Traverse E -E', several locations <br />along Traverse F -F', the edge of the Traverse I -I' roadway as it climbs out of the Deer Creek <br />drainage, and on the MDW E4 -14 pad along the same traverse. All subsidence - related <br />features were within the expected angle of draw for the E -seam and generally focused in <br />areas of maximum temporary tensile stress, such as above moving longwall faces. <br />831 - 032.796 Wright Water Engineers, Inc. Page 37 <br />September 2014 <br />