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• <br />• <br />Spring 2011 Subsidence and Geologic Field Observations <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />4.0 OVERVIEW OF SPRING 2011 FIELD STUDIES <br />This subsidence report is the first of two reports to be generated based on observations made <br />during the 2011 calendar year. Biannual reporting of subsidence related observations have <br />occurred since spring 2007. In accordance with MCC's Colorado Division of Reclamation, <br />Mining and Safety (CDRMS) permit, subsidence reports are submitted by April 30 (for <br />preceding fall monitoring) and September 30 (for preceding spring monitoring). Springtime <br />observations are regularly hampered by limited access due to snow or muddy conditions as <br />occurred this year and fall observations are scheduled around the various hunting seasons. <br />Persistent snowstorms, additional precipitation and muddy conditions throughout May and much <br />of early June prevented field activities until June 20 and 21 <br />Spring 2011 subsidence observations were conducted in the Box Canyon, Apache Rocks, SOD, <br />and Dry Fork mining areas. Field observations were made from a 4 -wheel drive vehicle and by <br />foot to efficiently complete the required work. <br />Prior field observations and experience in the West Elk Mine area over the last sixteen years' <br />(1996 to 2011 inclusive) indicate that subsidence features (cracks and bulges) are most visible on <br />roads and trails, where the ground is more compact and free of brush. These areas were therefore <br />selected, in addition to undermined areas free of brush, in order to most efficiently obtain <br />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 />visited photographic observation points), and to record their condition for future reference (Maps <br />1 -4). <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, 60B, <br />60C, 60D, and 60E). <br />831 - 032.793 <br />September 2011 <br />Wright Water Engineers, Inc. Page 13 <br />