Analyses of cascading failure in mine ventilation system and its effects in a serious mine gas explosion disaster

Abstract

In 2009, a serious gas explosion happened in Tunlan coal mine at Shanxi province, P.R. China, which claimed the lives of 78 miners. 114 miners got injured, and nearly 4 million dollars of economic loss was reported. According to the investigation report, the mine gas explosion was originally from a buildup of gas catching a flame in the underground. The happening of such accumulation was actually caused by functional failures of the mine ventilation system so that the concentration of gas reached the lower flammable limit. Technically speaking, the mine ventilation system is an integrity system. Any unit's failure can lead to other units losing their normal functions until the whole system breaks down. In other words, a cascading failure may happen. Based on the Tunlan mine disaster, this article introduces the concepts of cascading failure in the subject of mine ventilation engineering, which include the development process of failure, the mechanism, and the corresponding failure criteria, etc. The software "VentGIS simulator" is used as a tool to investigate the failure that occurred and its effects in the mine ventilation system. The coupled relationships between the failure mechanism and the gas explosion and its propagation are quantitatively studied in-depth. The research efforts show that (1) unreasonably installed the ventilation regulators directly caused the buildup of mine gas, which means an initial failure in a local ventilation system had appeared. Thus, one requirement of the gas explosion was provided; (2) failures of the early-warning system and mitigation measures led to the propagation of gas explosion shock in the underground mine network. Hence, impacts by the explosion are greatly enhanced. The research results presented in this article can be used as theoretical guidelines for improving the safety of a mine ventilation system or assisting to design a new one in the future. © 2013 ASM International.