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West Elk Mine <br />1. The existing longwall panels at the mine site have been extensively monitored and WWE <br />has evaluated the relevant data. These data provide the basis for Mr. Dunrud's conceptual <br />model, which is described later within this permit text and in Exhibit 60. Please note that <br />Exhibit 60 addresses the Apache Rocks and Box Canyon mining azea and Box Canyon <br />lease tract. Exhibit 60C addresses the subsidence and geologic hazards for the West <br />Flatiron lease tract. <br />2. WWE has utilized a computer model to quantify subsidence, and this model has been <br />calibrated using the data collected at the West Elk Mine. The model was developed by Dr. <br />Syd Peng and Dr. Yi Luo at West Virginia University and is referred to as the <br />"Comprehensive and Integrated Subsidence Prediction Model (CISPM)." <br />3. WWE has thoroughly reviewed the literature regarding subsidence and associated <br />hydrologic consequences. We have checked the findings associated with Mr. Dunrud's <br />conceptual model and the CISPM model with findings from case studies as described in <br />the literature, and we have concluded that the results are consistent. <br />4. Finally, subsidence projections described herein have been carefully reviewed by Richard <br />Dunrud for reasonableness. Mr. Dunrud has visited the West Ells Mine area on many <br />occasions and he is quite familiaz with all of the key factors pertaining to subsidence as <br />they relate to the Apache Rocks and Box Canyon mining areas. Consequently, Mr. Dunrud <br />is well qualified to draw conclusions about the nature of subsidence that is likely to occur. <br />• Subsidence Survev - 2.05.6 (6)(b)(iii)(A) & (61(e) <br />The following information documents subsidence processes that Have been observed from studies <br />above longwall mining panels in the current West Elk Mine permit azea. The subsidence data <br />obtained in the current West Elk Mine area have been used to project subsidence processes, <br />amounts, and effects into the Apache Rocks and Box Canyon mining aeeas. These data have been <br />used to calibrate the subsidence prediction models described above. <br />In addition to relying on actual subsidence data, WWE has concluded that many of the findings <br />pertaining to subsidence and probable hydrologic consequences from the Apache Rocks permit <br />revision (PR06) apply to the Box Canyon permit revision and mining azea. The basis for this <br />conclusion is as follows: <br />Comparison of lithologic data from boreholes in the Jumbo Mountain, Apache Rocks and <br />Box Canyon mining areas show consistency in the B-seam overburden materials. While <br />direct correlation of lithologic units, excluding coal beds, is generally difficult, comparison <br />of lithologic logs shows very similaz alternating sequences of shales, claystones, and <br />sandstones. In the Box Canyon mining azea, a noted exception is the occurrence of the <br />Ohio Creek Member of the Mesaverde Formation and the Wasatch Formation, which <br />comprises the upper reaches of West Flatiron. However„ its lithologic chazacter is similaz <br />to the Barren Member of the Mesaverde Formation which underlies it. <br />• • Both aeeas contain similaz topographic features. The Apache Rocks and Box Canyon <br />mining areas contain a much more extreme range of topographic relief, mostly due to their <br />2.05-100 RevisedJun.l995 PR06; !/96 RN03; Revised May 7999 TR89;Revised Jan. 1998 PR08;March 2005 PR11 p-1 <br />~l~ <br />