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I, personnel. These local tremors may affect underground workings; landslide or potential rock fall areas, particulazly during prolonged periods of increased precipitation. It is noteworthy, however, that the Rulison nuclear shot in 1969, which produced a tremor with a Richter magnitude of 5.2 (many times greater than the magnitudes of any recorded bump or rock burst), did not affect the Somerset Mine, and did not trigger any known landslides or rockfalls. In contrast to seismic effects generated by bumps and rock bursts that aze sometimes felt at the surface a mile or more from room-and-pillar mining operations, the initial cave in a longwall panel may well generate the largest seismic event. In some longwall mines which have thick and strong roof rocks, the initial cave may not occur for several hundred feet; and thus, can generate a shock wave through the mine and overburden that can be felt at the surface for considerable distances from the mine. However, the initial observed cave in the West Elk Mine occurs in 0 to 45 feet from the start of the panel. MCC has experienced no measurable seismic events at the surface due to initial longwall caving and bumps originating from the mine. Because the roof conditions are similaz ni the Apache Rocks and Box Canyon mining areas, MCC does not anticipate any different seismic effects in these areas than has been experienced in the current mining area. Subsidence Related Phenorr-ena 2.05.6(6)(e)(ii)(A-Cl ' Based upon the anticipated subsidence phenomena previously described in this section, and the lack of structures and renewable resource lands, MCC and WWE concludes that there will be little, if • any, damage or destruction of reasonable use within the current permit area. The "worst possible consequence" to the newer, wood-framed buildings and livestock enclosure would be complete destruction. The building that is apparently utilized as a "hunting cabin" was constructed after the SNW longwall panel was developed and lohgwall mining in this panel had begun. The smaller "bunkhouse" building and livestock enclosure were constructed after longwall mining was complete in both the SNW and 6NW lorigwall panels. They are located approximately over the eastern-most pillaz of the SNW longwal4 panel headgate, near cross-cut #17 and approximately 90 feet southeast of monitoring well SOM C-72H. The landowner had been provided updated mine plans in December 1993, and thus, was awaze that mining would occur under the site. ' The influence of subsidence, based on a conservative twenty-five degree (25°) angle-of--draw and an overburden depth of approximately 800 feet, the vicinity of the building in late November 1994, and was two cross-cuts past it by late December 1994. The building and site were measured, surveyed and photographed in eazly November 1994, prior to possible subsidence impacts. Subsequent surveys and photographic records were begun in early December 1994, and were continued approximately weekly until January 1995, then bi-monthly through March 1995, when mining of the panel was completed. Regular monitoring (weekly, then bi-monthly, as above) were conducted when the 6NW longwall panel was mined past this azea. Maximum subsidence, as presented in Exhibit 60, is not expected at this location, but maximum stresses are anticipated, as the building is located at the edge of the panel. ,Because MCC will compensate • for, repair or replace the building 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). 2.05-133 March 2005PR1] ~ ~ ~~Ati