2013-02-27_PERMIT FILE - C1981044

Home Browse Search

combustion. If these features are connected to the underlying mine, they may become important ventilation pathways in the future as the fire approaches this portion of the abandoned mine. Immediately adjacent to, and south of the vertical cut slope, is a bench from which at least eight boreholes were drilled.The surface expression of the fire is intermittent in this area, with only small vents observable. These vents are typically seen near the southern margin of the area, and exhibit low temperatures, generally less than 140 °. Ground surface temperatures near the eastern portion of the Central / Bench Zone have been measured in the 200° range. The bench area is well used by wintering cattle, as evidenced by an ample supply of cow manure covering the area. In June 2002, some of the manure on the bench area was smoldering in response to elevated ground surface temperatures. Due to the fire hazard presented by the smoldering cow manure, the Division hired a contractor to scrape the manure from the Central / Bench Zone.The manure was removed from the area, soaked with water and mixed with dirt to eliminate the fire potential. The northeastern most extent of the Central / Bench area exhibits a single vent located at 400 25'40.6", 1070 38'43.2". This vent is small, measuring about four by eight inches, but exhibits temperatures measured at 5250. Oxygen emissions from the vent were measured at 11.2 %, and carbon monoxide was measured at 435 parts per million. The ground surface in the vicinity of the smoldering manure feels and sounds hollow when struck with a heavy object. This, in conjunction with the broad surface area of elevated temperatures gives the impression that the underlying fire is relatively near to the ground surface, and that it has significantly weakened the overlying rock. South Zone This area is south east of the Central / Bench Zone. The area consists of a bench sloping upward toward the east, and the remnants of two mine access roads. The roads arc located on a cut slope below the elevation of the sloping bench, overlooking the adjacent canyon. The southerly burn zone is characterized by a few small vents located on the sloping bench, and a large, open vent located on the upper access road remnant. The cut slope between the large open vent and the smaller bench vents exhibits numerous conchoidal fractures, many of which vent the fire. 50 The cut slope venting fracture area, located at 400 25'37.0" 1070 38'42.8", is about 40 feet in length, by about 12 feet high. The area exhibits ground surface temperatures of 125° to 160 °. It is likely that the coal outcrop is involved in the fire at and near this location. A large vent, measuring three and one half feet by two and one half feet is located on the road remnant about 25 feet due east of the slope fracture zone noted above. This vent exhausts visibly blue smoke, and is the site of significant creosote deposition. The ground temperature at the vent was measured at 2251, with oxygen content of the exhaust measured at 12.6% and carbon monoxide measured at 375 parts per million. Significant conchoidal fracturing is observable in the road cut slope immediately south of this feature.These fractures vent combustion gasses, and exhibit temperatures of about 225 °. The large vent was backfilled by the Division of Minerals and Geology in June 2002 due to the safety hazard presented by the feature. It will be interesting to note how the adjacent fracture sets react to closure of the vent. General Observations: There appears to be as many as four distinct burn zones. These may be discontinuous as a result of the combustion of more than one coal seam, or as a result of roof falls or other under- ground impediments. Alternatively, the appearance of discontinuity may be the result of surface venting rather than of actual spatial separation of underground burn zones. Portions of this fire appear to be amenable to abatement activities. The Central / Bench and South zones easterly areas may involve combustion of near surface rider seams. The Highway zone appears to vent a relatively deeper fire than the more southerly areas. Drill data indicates that the fire does not present a hazard to the highway. The Central / Ridge area appears to be the hottest and most active fire zone.This area is well vented and apparently burning rather vigorously as evidenced by the significantly elevated surface temperatures.