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Fall 2009 Subsidence and Geologic Field Observations <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />• 4.0 OVERVIEW OF FALL 2009 FIELD STUDIES <br />This subsidence report is the second of two reports to be generated for observations made during <br />the 2009 calendar year. Biannual reporting of subsidence related observations have occurred <br />since spring 2007. According to the permit, such reporting is to be submitted to Colorado <br />Division of Reclamation, Mining and Safety (CDRMS) by April 30th and October 31St. However, <br />springtime observations are regularly hampered by limited access due to snow or muddy <br />conditions as occurred this year and fall observations are scheduled around the various hunting <br />seasons. For example, persistent snowstorms prevented field observations this April while <br />prolonged cooler weather caused additional precipitation and muddy conditions throughout much <br />of May. As a result, the spring 2009 field work was conducted in late May. Scheduling conflicts <br />hampered the fall observations which were finally conducted in late October between the second <br />and third rifle hunting seasons for deer and elk. <br />Fall 2009 subsidence observations were conducted in the Box Canyon, Apache Rocks, SOD, and <br />• Dry Fork mining areas. Field observations were made from a 4-wheel drive vehicle and by foot <br />to efficiently complete the required work. <br />Prior field observations and experience in the West Elk Mine area during field studies over the <br />last fourteen years' (1996 to 2009 inclusive) indicate that subsidence features (cracks and bulges) <br />are most visible on roads and trails, where the ground is more compact and free of brush. These <br />areas were therefore selected, in addition to undermined areas free of brush, in order to most <br />efficiently obtain maximum subsidence information. <br />The rockfalls and landslides in the Box Canyon, Apache Rocks, and SOD mining areas were <br />examined and photographed to evaluate changes since the last observation (using routinely <br />' Annual subsidence and geologic hazard reports are kept at Mountain Coal Company, LLC and at the Colorado <br />Division of Reclamation, Mining, and Safety, as well as exhibits to the permit document (Exhibits 60, 60A, 6013, <br />• 60C, 60D, and 60E). <br />831-032.791 Wright Water Engineers, Inc. Page 15 <br />April 2010