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West Elk Mine <br /> <br />2.05-115 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 />floors of the longwall panels are loaded with caved roof rocks and overlying strata before deformation <br />in the floor can occur. <br />Floor heaving, pillar punching (the pillar punches into the floor and roof rocks), and squeezing (plastic <br />flowage, see Dunrud 1976 for more details) are the only expected deformation in the immediate mine <br />floor, which consists of impure coal, shale, sandstone and claystone. Deformation in the floors of the <br />chain pillars is expected to occur after the longwall panel is mined and the pillars begin to yield. <br />Possible Subsidence Consequences <br />Southern Panels, SOD, Apache Rocks West, Dry Fork and Sunset Trail Mining Areas – <br />Modeled and predicted subsidence impacts for the mining areas has been provided in the Exhibit <br />60 through 60E series as well as Exhibit 84. Subsidence features observed to date have been <br />reported in MCC’s subsidence monitoring reports that have been submitted quarterly to the <br />CDRMS as required. <br />Potential Impacts from Local Seismic Activity <br />Earth tremors have been recorded or felt by local residents in the Somerset area since the early 1960s. <br />The tremors commonly are the result of coal mine bumps and rock bursts, which are spontaneous <br />releases of strain energy in highly stressed coal and rock. In the Somerset Mine area before closure, <br />the bumps and rock bursts were common in room-and-pillar mining areas where stresses concentrated <br />within isolated pillars and blocks of coal (called bump blocks). Earth tremors have continued <br />sporadically in the Somerset Mine area since the mine was closed. <br />Tremors generated by bumps and rock bursts in the Somerset Mine area attain magnitudes that have <br />shaken structures in the West Elk Mine area and have been felt sometimes by West Elk Mine <br />personnel. These local tremors may affect underground workings, landslide or potential rockfall <br />areas, particularly during prolonged periods of increased precipitation. It is noteworthy, however, <br />that the Rulison nuclear shot in 1969, which produced a tremor with a Richter magnitude of 5.2, was <br />many times greater than the magnitudes of any recorded coal bump. To Mr. Dunrud’s knowledge, the <br />Rulison nuclear shot did not trigger any known landslides, rockfalls, did not affect the Somerset <br />Mine, neither did it impact reservoirs, ponds, nor streams in the Southern Panels mining area. <br />In contrast to microseismic effects generated by bumps and rock bursts that are sometimes felt at the <br />surface a mile or more from room-and-pillar mining operations, the initial cave in a longwall panel <br />may well generate the largest seismic event. In some longwall mines which have thick and strong <br />roof rocks, the initial cave may not occur for several hundred feet, and thus, can generate a shock <br />wave through the mine and overburden that can be felt at the surface for considerable distances from <br />the mine. However, the initial observed cave in the West Elk Mine has occurred in 0 to 45 feet from <br />the start of the panel. MCC has experienced no measurable microseismic events at the surface due to <br />initial longwall caving and bumps originating from the mine. <br /> <br />Detailed Description of Damage or Diminution of Reasonable Use Which Could Result from <br />Subsidence Related Phenomena 2.05.6(6)(e)(ii)(A-C)