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Fall 2007 Subsidence and Geologic Field Observations <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />• <br /> <br />• <br />5.0 TRAVERSES AND OBSERVATIONS IN THE BOX CANYON, APACHE <br />ROCKS, AND SOD MINING AREAS <br />A detailed discussion of observations associated with traverses A-A' through I-I' is provided <br />below (see Maps 1 and 2). In many circumstances, photographs of locations observed during the <br />September, 2007 field survey are compared to photographs taken in previous years (Appendix <br />D). The photographs taken during the most recent field observations are included as figures in <br />the text of this report, whereas comparative photographs taken in previous years are included as <br />figures in Appendix D and referred to in the report text with a letter "D" before the figure <br />number. <br />5.1 Traverse A-A' <br />Traverse A-A' begins at well site E-seam methane exploration well no. 1 over mined longwall <br />panel 13, travels along the main access road to the Box Canyon mining area, and ends at the fork <br />in the drill roads (at B of traverse B-B') above the southern edge of mined longwall panel 14. <br />The traverse winds its way above mined longwall panels 13, 13A, 17, 16, 15 and 14. Light gray <br />to brown soil, colluvium, and local outcrops of siltstone and sandstone of the Barren Member of <br />the Mesaverde Formation occur in the road cuts. Overburden depth to the B-seam varies from <br />1,000 to 1,650 feet. The colluvium and soil are locally unstable on the roadcuts in the steeper <br />areas along the traverse, which causes landslide deposits, primarily on the steep slopes that are <br />common on the first two-thirds of the traverse. <br />The small soil/colluvial failure in the road cut, which was observed at location 1 during the <br />spring observations, was not observed in the fall traverse. The failure area had apparently been <br />cleaned up and obscured by summer road maintenance operations. <br />No subsidence features were observed. <br />831-032.780 Wright Water Engineers, Inc. Page 14 <br />November 2007 <br />