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Fall 2017 Subsidence and Geologic Field Observations <br />South of Divide and Dry Fork Mining Areas <br />4.0 FALL 2017 SUBSIDENCE OBSERVATIONS <br />During our fall 2017 field visit, subsidence -related tension cracks were observed above E -seam <br />Longwall Panels E5 and E6 in the SOD and Dry Fork mining areas along some drilling roads <br />accessed by USFS Road 711 (Dry Fork Road) and on MVB pads, particularly where they exist <br />above active mining activities. <br />Subsidence features were observed at various locations along the established traverses. All <br />subsidence features were located west of MVB E6-10 above the recent longwall mining activities <br />of E -seam Longwall Panel E6 (i.e., areas of maximum expected dynamic subsidence effects). No <br />subsidence features were observed in association with the most recent longwall mining beneath <br />Longwall Panel E7 as of the fall 2017 field observations. Details associated with the fall 2017 <br />observation of subsidence features can be found in Sections 4.2, 4.3, 4.4, and 4.5 of this report. <br />Relative to previously observed subsidence features discussed in earlier subsidence reports, all <br />were noticeably weathered and less discernible. To date, there have been no subsidence -related <br />features observed in alluvium even above active longwall mining activities. <br />The following sections of this report provide a description of the fall 2017 observations associated <br />with Traverses A -A' through F -F' (see Maps 1 and 2). Map 1 shows the outline of E -seam mine <br />workings along with surface topography and other surface features, including the named traverses. <br />Map 2 shows the same area and detail as Map 1 (minus traverses) along with recently active, or <br />potentially active, landslide and rockfall areas as delineated from aerial photo research and field <br />observations. <br />Some of the numerous photographs obtained during the fall 2017 field visit are included as figures <br />in the following text. Where these images have notable differences from previous photographs, <br />the older image has been included for comparison purposes. To reduce the overall size of this <br />document, narrative text and photographs are excluded for traverses where no noticeable change <br />was observed. <br />831-032.799 Wright Water Engineers, Inc. Page 10 <br />February 2018 <br />