The U.S. Bureau of Mines undertook a study of those factors influencing worker escape from an outby coal mine fire. Results of this investigation were twofold. First, those factors affecting escape from a mine fire were defined, and second, the relationships between these factors were identified. Although individual components had been studied before, little information was available on their interdependence. Fault tree analysis was used to evaluate the miner escape scenario. After constructing the fault tree, a two- phase analysis of the tree was conducted. During the first phase, the minimal cutsets of the fault tree were identified and ranked. These sets were the smallest sequence of events leading to fatalities during the fire. This ranking revealed that reduced evacuation delays, improved self-rescuer training, and improved stopping construction were important in controlling fatalities during escape from the mine fire. The second phase involved additional analyses of the fault tree. These evaluations were started by first determining occurrence probabilities for each event in the fault tree. Two types of sensitivity analyses were then conducted. The first analysis dealt with changes in event probabilities and their impact on the likelihood of fatalities. The final sensitivity analysis considered dramatic reductions in the probability of fire fatalities. This revealed what event probability values were necessary to reach this level. These results have revealed various remedial actions that could be used to improve the survivability of an outby mine fire.
Trans. AIME/SME, V. 286, July, 1990, PP. 1801-1805