Tenability analysis for improvement of firefighters’ performance in a methane fire event at a coal mine working face

Abstract

Due to the high rate of methane ignitions at active continuous miner working faces in underground coal mines, this location has been the focus of many researchers, as well as safety initiatives. Multiple ignitions occur annually in US mines, and outcomes vary widely based on the magnitude of the ignition and the subsequent damage to ventilation controls or development of active fire. Depending on the magnitude of the explosion or fire, auxiliary ventilation controls, such as exhausting line curtain or tubing may be damaged or completely removed, affecting the ventilation into the area. Investigation of a typical dead end continuous miner working face with exhausting ventilation was undertaken to explore firefighting conditions post ignition. Regular mining crews are trained in the fighting of mine fires, while mine rescue or fire brigade teams may also be utilized for firefighting depending upon the conditions. The research in this article develops an approach to analyze the tenable limits in a fire event in an underground coal mine for barefaced miners, mine rescue teams, and fire brigade teams in order to improve safety and training of personnel trained to fight fires. A detailed computational fluid dynamics analysis was conducted to investigate temperature, visibility, radiation, and concentration of combustion products based on different damage assumptions following an ignition at the continuous miner working face. The source of the combustion products analysis and the exposure effects were considered to assess the potential for harm to mine personnel, mine rescue teams, or fire brigades during a firefighting operation, taking into account their training and personal protective equipment during the 5- and 15-min exposure. This study has shown that if the exhausting line curtain was destroyed, the situation would not be tenable for barefaced personnel. The findings were utilized to recommend the tenable limits for barefaced miners, mine rescue team, and fire brigade teams during the 15-min exposure to the methane fire at a continuous miner working face. The outcome of this research, applied to training, will result in the more efficient evacuation, as well as safe and effective firefighting under certain conditions.