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West Elk Mine <br />has already been obtained prior to any mining in the South of Divide mining area. A pre-mining survey of the <br />Dry Fork Cow Camp was performed by Wright Water Engineers in July 2004 and was reported in Exhibit 60D, <br />and another survey was conducted by West Elk Land Surveying in February 2006 and is included in Exhibit 73. <br />Another detailed pre-subsidence survey of the Cow Camp was conducted within six months prior to longwall <br />mining and subsidence taking place. A survey monument was placed in the vicinity of the structures as part of this <br />inspection and its location was surveyed prior to subsidence. The quarterly surveys of the monument will be <br />continued while it is within the calculated angle of draw of subsidence (access and ground conditions pennitting) <br />and until two consecutive measurements show no significant movement. These data will be reported in the <br />subsequent semi-annual subsidence report. The structures will be resurveyed after subsidence movement is <br />complete (per the monument survey above) and a summary report detailing changes to the buildings, if any, will be <br />included in the subsequent semi-annual subsidence report. <br />Although no buildings are anticipated to be impacted by the projected E-seam mining in the Dry Fork Lease area <br />(see Map 51), the Ditch Rider's Cabin shown on Map 66 and included in the inventory of structures on Table 42A, <br />could be impacted by subsidence should planned mining of longwall panel E6 be extended more than 3,000' and <br />under the cabin location within the Projected Potential Mining Area shown on Map 51. The worst possible <br />consequence from subsidence to this cabin is anticipated to be similar to that of the Dry Fork Cow Camp as <br />described in Exhibit 60E. Foundation cracks could occur, but the building is expected to remain intact and usable. <br />Similar to the Cow Camp, a survey of the cabin would be completed prior to longwall mining and again after <br />mining is complete in the area and as soon as access and ground conditions allow. <br />Lower Dry Fork Cow t.amn <br />The cabin exterior is approximately 13 feet wide, 20 feet long, and 8.5 feet high (the wall height). A lean-to 7 feet <br />long and a porch 5.5 feet wide are located on the north and south ends of the cabin (see Figures 7 and 8, of Exhibit <br />60D for details). The outside walls are of a wood, board-and-bat construction. <br />The foundation, which is of rock and mortar construction (and an estimated 11/2 feet thick), ranges from about 1 <br />foot high in the back to 20 inches high in the front. The roof is covered with tin. The side windows, which <br />measure 2 by 3 feet in outside dimension, are located in the approximate center of either wall. <br />Estimated maximum ranges of vertical displacement (SO, tilt (MO, and horizontal tensile and compressive strain <br />(E. and Em) in the cow camp cabin area are as follows, assuming 14 ft of coal is extracted (see Table 2, Exhibit <br />6013): Sm=9-loft; Mm=2-5%; Em,-Em=0.8-3%. <br />As the longwall mining face moves westward within the area of mining influence of the cabin, a subsidence <br />wave--moving at about the same rate as the mining face- will pass beneath the cabin, subjecting it to (1) tilt and <br />strain, (2) then maximum vertical displacement, (3) then relaxation of these effects, as the longwall mining face <br />moves out of the area of mining influence. <br />The cabin, though temporarily tilted until the longwall face moves out of the area of influence of the cabin, is <br />expected to remain intact during the subsidence episode, because it is small and light, and of wood construction. <br />However, cracks are expected to occur in the foundation, in response to the tilt and strain caused by the subsidence <br />wave produced by the moving longwall mining face below. <br />The cracks, which may reach a maximum temporary width of a fraction of an inch to perhaps 1 to perhaps 1'/< <br />inches, will likely close again when the longwall mining face moves out of the area of mining influence of the <br />cabin. Any cracks that develop in the foundation, however, may continue to be visible for the life of the <br />foundation. <br />Cracks, of as much as 1 to perhaps 1'/, inches wide, are also expected to locally occur in the Dry Fork road near the <br />Cow Camp and elsewhere during mining. The cracks will likely close again once the longwall mining face moves <br />out of the area of influence of the road area. <br />2.05-157 Rev. 06105- PRIO, 03106- PRIG, 05106- PRIO, 111060- 78107, 04107- TRI08. 09107 PRIZ 02108- PR12, 11/10- TR124