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enclosure), Forest Service roads, ditches, trails and stock ponds, and MCC's <br />hydrologic monitoring stations. The renewable resource lands identified in the <br />PR-10 inventory are the water-bearing bedrock and alluvial strata in and <br />adjacent to the South of Divide area. <br />Structures identified in the PR-12 (Dry Fork lease) inventory are: U.S. Forest <br />Service Roads 711 and 711.5, the Deep Creek Ditch, the Minnesota Creek <br />Ditch Rider's cabin, trails, stock ponds, and MCC's hydrologic monitoring <br />stations. The renewable resource lands identified in the PR -12 inventory are <br />the water-bearing bedrock units in and adjacent to the Dry Fork lease area. <br />b. Possible Subsidence Consequences and Mitigation of Impacts <br />Possible subsidence consequences are described in Section 2.05.6(6)(b)(1) of <br />the permit application. Additional information is contained in a report in <br />Exhibit 55, titled "Subsidence Evaluation for the West Elk Mine". <br />Information for specific areas in the permit area can be found in Exhibit 60. <br />MCC's predictions of possible subsidence are based on historical observation <br />from past mining, conceptual analytical modeling (relation between extraction <br />height and workings depth, adjusted for lithologic variation), and numerical <br />modeling (computed influence function). MCC predicts the angle of draw for <br />longwall mining in the E seam in the Dry Fork lease area will be 21 degrees. <br />(The angle of draw is the angle between a vertical line at a panel edge and a <br />line extending from the panel edge to the point of zero subsidence at the <br />ground surface.) MCC predicts the angle of draw for longwall mining in the E <br />seam in the South of Divide area will be between 10 and 20 degrees. MCC <br />predicts 95 percent of subsidence will have occurred at a location in the Dry <br />Fork lease area when the longwall face has moved from the location a distance <br />equal to 1.0 to 1.2 times the depth of mining. The depth to mining in the Dry <br />Fork lease area will range between 800 and 1,400 feet, with maximum vertical <br />displacement on the land surface of 7.0 feet. The depth to mining in the South <br />of Divide area will range between 375 ft. and 1,300 ft. Maximum surface <br />crack depth is predicted to occur in brittle sandstone ridges, as observed <br />elsewhere in the permit area, with maximum crack depth of 50 feet. Maximum <br />crack depth is predicted to be 5 to 15 feet on gently sloping land (00%). <br />Surface cracks are predicted to not occur where mining depth is is several <br />hundred feet and alluvium is more than a few feet thick. <br />Possible subsidence effects on ground water has been previously discussed in <br />this Findings document under the heading "Probable Hydrologic <br />Consequences". <br />MCC predicts the mining nearest State Highway 133 (600 feet horizontal <br />distance) will probably not re-activate existing landslide deposits in the area <br />because the mining there consists of room-and pillar development entries <br />47