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FALL 2018 SUBSIDENCE AND GEOLOGIC FIELD OBSERVATIONS <br /> SOUTHERN PANELS MINING AREA' <br /> 1.0 BACKGROUND <br /> This subsidence report is the second of two detailed documents on this subject to be generated <br /> based on 2018 calendar year observations. These biannual reports of subsidence-related <br /> observations at the West Elk Mine have occurred continuously since spring 2007 and annually <br /> between 1996 and 2006. In accordance with Mountain Coal Company, LLC's (MCC) Colorado <br /> Division of Reclamation, Mining and Safety(CDRMS)permit, these subsidence reports are to be <br /> submitted by April 30 (for preceding fall monitoring) and September 30 (for preceding spring <br /> monitoring). <br /> Prior field observations and experience in the West Elk Mine area over the last twenty-three years <br /> (1996 to 2018 inclusive) indicate that subsidence-related features (cracks and bulges) are most <br /> visible on roads,well pads, and trails,where the ground is more compact and free of brush. These <br /> areas have been, and will continue to be,the focus of the biannual observations to most efficiently <br /> obtain subsidence information. Other subsidence features such as rockfalls and landslides are <br /> generally observable from overview locations along roads or on well pads and have been, and will <br /> continue to be, noted when they occur. <br /> Fall 2018 subsidence observations were performed on October 19, 2018, in the Southern Panels <br /> Mining Area with specific focus on the current(E-seam Longwall Panel E7)and two most recently <br /> mined longwall panels (E-seam Longwall Panels E5, and E6). Pre-mining observations were also <br /> made of the area over E-Seam Longwall Panel E8. As a result,the previously established traverse <br /> names have been changed and will likely change with each successive report. Observations <br /> 1 The Southern Panels Mining Area includes the E-seam Longwall Panels E1 through E9 originally included in the <br /> South of Divide Mining Area and some of which were extended into the Dry Fork Mining Area. The Southern Panels <br /> Mining Area also includes B-seam Longwall Panels B26 through B29 that underlie E-seam longwall panels E1 <br /> through E5. The term South Panels Mining Area will be used throughout this report to identify what was formerly <br /> referred to as the South of Divide and Dry Fork mining areas. <br /> 2 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,60C, <br /> 60D,and 60E). <br /> 831-032.900 Wright Water Engineers, Inc. Page 3 <br /> April 2019 <br />