Correlation between methane and fire hazards in abandoned workings of longwall mining

摘要

In underground coal mines, fire and methane explosion hazards are considered the most perilous. Those hazards are especially risky when exploitation of methane coal seams susceptible to self-ignition is undertaken. In this paper, an evaluation of fire and methane explosion hazards based on Graham's, La Chatelier's and oxygen indexes as well as an approximate temperature of burning gases is presented. It is proposed that during exploitation of methane coal beds susceptible to self-ignition, the probabilities of gas explosion or ignition are estimated based on systematic sampling of gas composition in abandoned workings. This approach would allow a numerical value to be assigned to the risk of gas explosion or ignition and would provide basis to undertake preventive action to reduce or eliminate those hazards.