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Subsidence and Geologic Field Observations <br />Apache Rocks and Box Canyon Mining Areas <br />July 12.15, 2004 <br />Figure 4. Landslide and rocklall area, located above un-mined longwall panel tg on the east side of Box <br />Canyon. This higher resolution Image was taken to provide a baseline Image of the IandsOde to compare <br />after mining Is completed. <br />• Overburden thickness (depth to B Seam) of the landslide ranges from about SOU feet, at the <br />toe. to 2,150 feet at the head scarp-a vertical distance of about 1.350 feet. The marimunt <br />horizontal length and width of the landslide is atwut 2,300 feet and 1,000 feet, respectively <br />(Map 1), <br />• 'I7tc head scarp looks the same as it did laet year prior to longwall mining. No changes in the <br />appearance of the gravity-induced cracks wetr observed from Inst year (see Figure 3 of the <br />2003 rcpon for details ofpre-mining cracks). <br />Location 3: <br />• Point is located I50 to 2U0 feet southeast of location above mined longwall panel 22. <br />Overburden depth to thr B Suun is about 2,200 feet. <br />837-032.640 Wright WeterEngine~rs, Int. Page t3 <br />September 2004 <br />