2024-01-22_PERMIT FILE - C1980007A (4)

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