2013-09-27_REPORT - C1980007 (4)

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Spring 2013 Subsidence and Geologic Field Observations South of Divide and Dry Fork Mining Areas (E -Seam) 3.0 OVERVIEW OF SPRING 2013 FIELD STUDIES This subsidence report is the first of two reports to be generated based on 2013 calendar year observations. Biannual reporting of subsidence related observations have occurred since spring 2007. In accordance with MCC's Colorado Division of Reclamation, Mining and Safety (CDRMS) permit, subsidence reports are to be submitted by April 30th (for preceding fall monitoring) and September 30th (for preceding spring monitoring). Spring observations are regularly hampered by limited access due to snow or muddy conditions and fall observations are typically scheduled around the various hunting seasons. Conditions were such this year that the spring 2013 field observations were made on June 13th and 14th. Prior field observations and experience in the West Elk Mine area over the last eighteen years' (1996 to 2013 inclusive) indicate that subsidence features (cracks and bulges) are most visible on roads and trails, where the ground is more compact and free of brush. These areas were therefore selected for observation to most efficiently obtain maximum subsidence information. Other more obvious subsidence features like rockfalls and landslides are generally observable from roads and trails or from overview locations which have, and continue to be, established for this purpose. Spring 2013 subsidence observations were performed in the SOD and Dry Fork mining areas. Considering the lack of observed subsidence - related observations in the Apache Rocks and Box Canyon mining areas since the completion of B -seam mining activities in late 2008, these areas were not visited and are not planned to be visited again for this purpose unless conditions substantially change. This change has prompted the naming convention changes for traverses and photographic observations points which have been relatively constant during the past several years. Attempts will be made to maintain these new names for several additional years as the E -seam mining activities in the SOD and Dry Fork mining area continue. As a consequence, previously - provided mapping associated with B -seam longwall mining have been excluded from this report. These maps can be found in reports prior to 2013. 'Annual subsidence and geologic hazard reports are kept at Mountain Coal Company, LLC and at the Colorado Division of Reclamation, Mining, and Safety, as well as exhibits to the permit document (Exhibits 60, 60A, 60B, 60C, 60D, and 60E). 831 - 032.795 Wright Water Engineers, Inc. Page 6 September 2013