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West Elk Mine Dunrud evaluated subsidence in the Mesaverde Formation at the Somerset Mine, less than two miles from the West Elk Mine. Working closely with Mr. Dunrud, WWE has adopted the following multi-faceted approach to quantifying subsidence in the pemut azea: The existing longwall panels at the mine site have been extensively monitored and WWE has evaluated the relevant data. These data provide the basis for Mr. Dunrud's conceptual model, which is described later in this permit text and in Exhibits 60 and 60B. Please note that Exhibit 60 addresses the Apache Rocks and Box Canyon mining areas and Exhibit 60B specifically addresses the South of Divide mining area. 2. WWE has utilized a computer model to quantify subsidence, and this model has been calibrated using the data collected at West Elk Mine. The model was developed by Dr. Syd Peng and Dr. Yi Luo at West Virginia University and is referred to as the "Comprehensive and Integrated Subsidence Prediction Model (CISPM)." 3. WWE has thoroughly reviewed the literature regarding subsidence and associated hydrologic consequences. We have checked the findings associated with Mr. Dunrud's conceptual model and the CISPM model with findings from case studies as described in the literature, and we have concluded that the results aze consistent. . 4. Finally, subsidence projections described herein have been carefully reviewed by Mr. Dunrud for reasonableness. Mr. Dunrud has visited the West Ells Mine azea on many occasions and he is familiaz with key factors pertaining to subsidence as they relate to the South of Divide and other active mining areas. Consequently, Mr. Dunrud is well qualified to draw conclusions about the nature of subsidence that is likely to occur. Subsidence Survev-2.05.6(6)(b)(iii)(A) & (6)(e) The following information documents subsidence processes that have been observed from studies above longwall mining panels in the current West Elk Mine pemut area. The subsidence data obtained in the current West Elk Mine azea have been used to project subsidence processes, amounts, and effects into the Apache Rocks and Box Canyon mining aeeas, and South of Divide mining area where only the E Seam coal is to be mined. These data have been used to calibrate the subsidence prediction models described above. In addition to relying on actual subsidence data, WWE has concluded that many of the findings pertaining to subsidence and probable hydrologic consequences from previous pernrit revisions apply to the South of Divide permit revision and mining area. The basis for this conclusion is as follows: • Comparison of lithologic data from boreholes in the Jumbo Mountain, Apache Rocks and Box Canyon mining areas show consistency in the B Seam overburden materials, including those units immediately above and below the E Seam coal. While direct correlation of lithologic • units, excluding coal beds, is generally difficult, comparison of lithologic logs shows very 2.05-95 Revised November 2004 PRIO