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West Elk Mine <br /> <br />2.05-116 Rev. 06/05- PR10, 03/06- PR10, 05/06- PR10, 11/060- TR107, 04/07- TR108, 09/07- PR12, 02/08- PR12; 11/10- MR372; 10/20- MR-452; <br /> 12/20- TR149; 12/21- TR150, 1/24-TR152, 2/25-MR486 <br />Based upon the anticipated subsidence phenomena previously described in this section, and the <br />general scarcity of structures and renewable resource lands, MCC and WWE conclude that there will <br />be little, if any, damage or destruction of reasonable use within the MCC permit area. <br />One structure that exists in the Dry Fork Basin and is known as Lower Cow Camp. This structure <br />is used by the cattle pool as seasonal living quarters for the range cowboy. The cabin is owned by <br />the USFS and leased to the Dry Fork Cattle Pool. This cabin and related corrals were inventoried <br />and are included in Exhibits 60D and 73. <br />Mining in the B Seam occurred in the vicinity of the building in late 1994. Regular monitoring <br />was conducted and no damage found. As MCC will compensate for, repair or replace this building <br />or any other structure or resource in compliance with CMLRB Rule 4.20.3(2), no material <br />subsidence damage will result, as defined by CMLRB Rule 2.05.6(6)(e)(ii)(A). <br />The "worst possible consequences" from mining to hydrologic resources, hydrology monitoring <br />stations, and the many trails and unimproved U.S. Forest Service roads could be complete loss of <br />surface water resources to the mine workings, total destruction of the stations and total destruction or <br />blockage of the trails on roads. MCC will repair or replace these items as discussed later in this <br />section. <br />Subsidence Monitoring Plan - 2.05.6 (6)(b)(ii), (6)(c)(i) and (6)(e)(iii) <br />A) Subsidence Monitoring <br /> <br />Until 1999, subsidence monitoring at West Elk Mine was accomplished using conventional survey <br />methods of a monument grid. The grid was laid out over the first three B seam longwall panels <br />mined (panels 1-3NW), and successfully verified MCC’s prediction about the amount of <br />subsidence. The grid is shown on Map 29. As subsidence of the three longwall panels was <br />completed and the surveys no longer showed movement, monitoring of the grid was discontinued <br />in 1999. The past monitoring of MCC’s subsidence grid established the amount of subsidence that <br />occurs over a longwall panel, when it occurs, where it occurs, and when it is complete; therefore, <br />there is no longer a need for additional grids. Instead, MCC visually inspects the ground over the <br />areas that have been undermined to document any disturbance that may have occurred. MCC also <br />visits new mining areas prior to any subsidence occurrence to document pre-existing conditions, <br />and also visits locations where cracks have previously been documented to verify that the cracks <br />are healing. MCC utilizes traditional survey methods, as necessary, to evaluate any structures of <br />concern. Also, MCC continues to conduct subsidence monitoring observations of the following: <br />roads, inverts of culverts, flumes, stock ponds, and buildings, Monument Dam, and Minnesota <br />Reservoir. <br />Specific subsidence monitoring measures and plans included the verification of the subsidence <br />angle-of-draw in the SOD and Dry Fork mining areas. The monuments established as part of the <br />baseline survey were resurveyed at least three months after the longwall face had moved past the <br />end of the longitudinal survey line to determine the amount of subsidence that has occurred and <br />the angle of draw of subsidence. A report detailing the angle of draw observed during the <br />aforementioned survey was submitted to the Division with the semi-annual subsidence report. To <br />verify the subsidence angle-of-draw in the SOD mining area, MCC completed a baseline survey <br />of the first E-seam panel, prior to the start of longwall mining, with survey-grade GPS equipment.