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Fall 2007 Subsidence and Geologic Field Observations <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />crack was observed during the spring 2007 field visit above this site after the drill road switched <br />back across this crack trend (see location Za of the spring 2007 report for details). However, a <br />fall reevaluation of this location suggests that the feature shown in Figure 7 of the spring 2007 <br />report is erosion induced by slope wash that was channeled dgwn the drill road above the area. <br />5.2.2 Location 2 (Location 3 of the Spring 2007 Field Visit) <br />Location 2 (Figure 6) is a rockfall located above the drill road to West Flatiron as described in <br />previous annual reports. The fall, which occurred on June 30, 2004, is located above the north <br />edge of the central part of mined longwall panel 14. A photograph of the same rockfall area <br />taken during the summer of 2006 is provided as Figure D-2 for comparison. <br />The overburden depth to the B-seam at this location is about 1,950 feet. Although longwall <br />panel 14 was mined about five years ago, and subsidence likely has been completed, subsidence <br />effects could still occur in these rugged cliff areas. <br />L`J <br />• <br />831-032.780 Wright Water Engineers, Inc. Page 17 <br />November 2007 <br />