Laserfiche WebLink
SPRING 2014 SUBSIDENCE AND GEOLOGIC FIELD OBSERVATIONS <br />SOUTH OF DIVIDE AND DRY FORK MINING AREAS (E -SEAM) <br />1.0 SUMMARY OF FINDINGS <br />On June 23 and 24, 2014, Wright Water Engineers, Inc. (WWE) observed subsidence and geologic <br />field conditions of the South of Divide (SOD) and Dry Fork mining areas (consistent with current <br />Exhibit 60E) for Mountain Coal Company, LLC (MCC). Similar observations have been made <br />annually since 1996 and semi - annually since 2007 as a means to assess potential longwall mining <br />effects on the environment. <br />Beginning with the Spring 2011 Subsidence Report, an effort has been made to reduce the size of <br />these semi - annual reports by eliminating 1 much of the background and historical information (e.g., <br />subsidence projections) included in eact of the previous reports. For this reason, the reader is <br />directed to Section 1.0 of the Spring 2011 Subsidence Report and to Exhibit 60 and 60E of the <br />West Elk Mine permit for specific details about subsidence projections. A condensed version of <br />the subsidence prediction information isl provided in the spring report each year as Appendix A. <br />Background information, such as field recognition of subsidence and non - subsidence features, can <br />also be found in the Spring 2011 Subsidence Report (Section 2.0) but is no longer included in the <br />semi - annual reports. <br />Based on field observations from 1996 to spring 2014, the effects of longwall mining above the <br />West Elk Mine have been less than initially projected as reported in Exhibit 60 (Dunrud, 1998 <br />rev.) and 60E (WWE, 2012). Rockfalls and/or landslides have generally been observed only <br />sporadically in the Box Canyon mining area since 2006 where the steep, upper reaches of Sylvester <br />Gulch and Box Canyon abut West Flatiron. Since 2009, that area has generally stabilized as the <br />mining- related activities in this area hove been completed. In the flatter and more rounded <br />topography of the Apache Rocks, SOD and Dry Fork mining areas, the rockfall and landslide <br />potential is much smaller. <br />Subsidence - related tension cracks were Observed during our spring 2014 field visit to the SOD and <br />Dry Fork mining areas along some drilling roads accessed by US Forest Service Road 711 (Dry <br />831 - 032.795 Wright Water Engineers, Inc. Page 1 <br />September 2014 <br />