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SPRING 2017 SUBSIDENCE AND GEOLOGIC FIELD OBSERVATIONS <br />SOUTH OF DIVIDE AND DRY FORK MINING AREAS <br />1.0 BACKGROUND <br />This subsidence report is the first of two required documents on this subject to be generated based <br />on 2017 calendar year observations. Biannual reporting of subsidence -related observations at the <br />West Elk Mine have occurred continuously since spring 2007. In accordance with Mountain Coal <br />Company's (MCC's) Colorado Division of Reclamation, Mining and Safety (CDRMS) permit, <br />subsidence reports are to be submitted by April 30 (for preceding fall monitoring) and September <br />30 (for preceding spring monitoring). <br />Prior field observations and experience in the West Elk Mine area over the last twenty-one years' <br />(1996 to 2017 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, discussed when they occur. <br />Spring 2017 subsidence observations were performed in the South of Divide (SOD) and Dry Fork <br />mining areas with specific focus on the two most recently mined longwall panels (i.e., Longwall <br />Panels E5 and E6). As a result, the previously established traverse names have been changed and <br />will likely change with each successive report. Observations associated with E -seam longwall <br />mining of Panels E1 through E4 (mined and subsided more than two years previous) can be found <br />in reports prior to 2016. Observations of the Apache Rocks and Box Canyon B -seam mining <br />areas are covered in reports prior to 2013. <br />During the spring 2017 field visit, accessible areas within the SOD and Dry Fork mining areas <br />were visited, examined and photographed to document subsidence -related features observed since <br />1 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 />831-032.799 Wright Water Engineers, Inc. Page 3 <br />August 2017 <br />