Spontaneous combustion occurring in inaccessible areas of underground coal mines is often intractable. Even though routine inspection and/or continuous monitoring help detect the incubation of spontaneous heatings, they may not be able to identify the locations with accuracy. Moreover, implementation of remedial measures is difficult. A new approach to ventilation system design to overcome the problem is investigated in this dissertation. Ventilation layouts are analyzed to identify potential problem areas and nullify the probability of fire occurrence. The focus is directed to longwall gobs. The changing gob characteristics, especially the varying degree of consolidation at different parts of a gob as the face moves, is considered. Analytical studies and computer modeling show that bleederless ventilation in retreating panels is promising. The W-system of ventilation is most suitable. However, there may be difficulties in maintaining the middle entry in a W-system. On the basis of an actual case study, a new layout is described that allows pressure balancing to be applied behind the face shield supports in a U-system. This minimizes airflow through the critical areas of the gob. Multiple entries and air pressure balancing are used in implementing the method, without affecting the normal airflow rate at the working face. In addition to such measures, a methane drainage system may be implemented in gassy mines. This can be accomplished by using a proposed gob gas drainage model compatible with the proposed ventilation system.
展开▼
