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Spring 2012 Subsidence and Geologic Field Observations <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />3.0 OVERVIEW OF SPRING 2012 FIELD STUDIES <br />This subsidence report is the first of two reports to be generated based on observations to be <br />made during the 2012 calendar year. Biannual reporting of subsidence related observations have <br />occurred since spring 2007. Spring observations are regularly hampered by limited access due to <br />snow or muddy conditions and fall observations are scheduled around the various hunting <br />seasons. Conditions were such this year that the spring 2012 field observations were made on <br />May 31 and June 1, 2012. <br />Spring 2012 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 seventeen years <br />(1996 to 2012 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. Other more obvious subsidence features like rockfalls and <br />landslides are generally observable from roads and trails or from overview locations which have, <br />and continue to be, established for this purpose. <br />Previously identified rockfalls and landslides in the Box Canyon, Apache Rocks, SOD, and Dry <br />Fork mining areas were examined and photographed to evaluate changes since the last <br />observation (using routinely visited photographic observation points), and to record their <br />condition for future reference (Maps 1 -4). <br />Thirteen photographic observation points have been established since 2007 (see Maps 1 and 2) to <br />view and assess changes that may occur as a result of mining. Many of these locations had been <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 - 032.794 <br />November 2012 <br />Wright Water Engineers, Inc. Page 6 <br />