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FALL 2012 SUBSIDENCE AND GEOLOGIC FIELD OBSERVATIONS <br />Box Canyon, Apache Rocks, and South of Divide Mining Areas <br />1.0 INTRODUCTION <br />Beginning in 2007, Wright Water Engineers, Inc. (WWE) has conducted semi- annual (spring <br />and fall) field visits to the area over the West Elk Mine as operated by Mountain Coal Company, <br />LLC (MCC) making subsidence and geologic observations. Prior to 2007, WWE performed <br />annual field visits dating back to 1996. Each of these visits provides observations related to <br />subsidence effects resulting from the longwall mining of coal in the B- and /or E -seam. These <br />observations have been subsequently chronicled in an annual or semi - annual subsidence report'. <br />This semi - annual subsidence report (Fall 2012 Report) is the second of two reports to be <br />generated based on observations made during the 2012 calendar year. In accordance with <br />MCC's Colorado Division of Reclamation, Mining and Safety (CDRMS) permit, subsidence <br />reports are to be submitted by April 30 (for preceding fall monitoring) and September 30 (for <br />preceding spring monitoring). <br />Field observations represent more than 80 percent of the text contained within each of the <br />subsidence reports. The remaining 20 percent is repeated reference text for the convenience of <br />the reader. As of the Fall 2010 Report, WWE and MCC made an effort to reduce the size of the <br />annual fall subsidence report by removing the regularly repeated reference text. Each fall report <br />makes reference to the spring subsidence report for those details that have been characteristically <br />repeated in previous reports (e.g., field recognition of subsidence and non - subsidence features, <br />conclusions, and a bibliography). This is true of Appendix A of the Spring 2012 Report, which <br />provides a summary of the subsidence prediction information contained in Exhibit 60 through <br />60E of the current permit issued by the CDRMS. As did the Fall 2011 Report, this subsidence <br />' Annual and semi - annual subsidence and geologic field observation reports, as well as exhibits to the West Elk <br />Mine permit document (Exhibits 60, 60A, 60B, 60C, 60D, and 60E), are kept at Mountain Coal Company, LLC <br />and at the Colorado Division of Reclamation, Mining, and Safety. <br />831 -032 794 <br />April 2013 <br />Wright Water Engineers, Inc. Page 1 <br />