Revised Explosibility Diagram to Judge Best Practice of Controlling an Explosive Gas-Mixture

Abstract

Gas explosions or mine fires present the safety threats for coal miners or mine rescues members. For an explosive atmosphere in the underground mine, careful determination of its explosibility status and applying some mitigations to switch an explosive atmosphere into a non-explosive one are very important for any underground rescues or a mine fire extinguishment. However, due to the complicated compositions in an underground sealed atmosphere, accurate determination of the explosibility of such atmosphere status is always a knotty problem for mining engineers. Beside of that, a proper estimation method for the needed time span when an explosive atmosphere is artificially or naturally changed into a non-explosive is also urgently desired. In order to improve the mine safety, this paper is going to address such mentioned problems. The original Coward explosibility diagram is modified with handling the combination effects of different inert gases for more accurate determining the explosibility of an underground sealed atmosphere which consists of complex gas compositions. Then, based on the revised explosibility diagram, a set of mathematical equations are theoretically derived to estimate the inertisation time of a sealed mine atmosphere by using different inerting approaches. Such research efforts can help mine operators understand the risk and provide a tool to control such atmosphere away from dangerous conditions. In order to demonstrate the research findings, at the end of the paper, the explosibility of gas sample taken from a real mine has been analyzed by using the revised Coward diagram. Also, the different inertisation time durations of various mitigation measures for such underground atmosphere have also been calculated.