PURPOSE:  To reduce hazards in mining through basic and applied research on the prevention and mitigation of gas and dust explosions and the education of mining personnel on explosion hazard recognition and prevention.

RESEARCH SUMMARY:  While much progress has been made in preventing disasters in mines, explosions still occur, often producing multiple fatalities. In an explosion, all underground miners are at risk. There were serious underground coal mine explosions in July 2000 at a Utah mine (2 fatalities and 8 injuries), in September 2001 at an Alabama mine (13 fatalities and 3 injuries), and in January 2003 at a West Virginia mine (3 fatalities and 3 injuries). Explosions are caused by accumulations of flammable gas and/or combustible dust mixed with air in the presence of an ignition source. Research on gas and dust explosions is needed as a basis for the development of techniques and strategies for explosion prevention, suppression, and mitigation.

This project studies explosion propagation and explosion combustion mechanisms through full-scale tests at the Lake Lynn Experimental Mine (LLEM) and through laboratory tests in a 20 liter chamber. The LLEM research includes the effects of turbulence and confinement on the initial stages of a gas explosion, the requirements for transition from a small gas explosion to a full-scale propagating dust explosion, and flame propagation in large volumes of nonuniformly mixed methane. In conjunction with these LLEM tests, there is a task to improve the supporting documentation/research used by the Mine Safety and Health Administration (MSHA) in investigating explosion disasters. In a collaborative task with MSHA, an in-situ meter has been developed to quickly determine the explosibility and/or the incombustible content of coal and rock dust mixtures in coal mines, thereby improving sample analysis and rock dusting practices.

The results of this research so far have been communicated to stakeholders in four briefing reports to MSHA, two conference papers, a book chapter, and a peer-reviewed journal paper. Achievements include the development of improved forensic procedures for use by MSHA in investigating mine explosion accidents and the development of improved laboratory test methods as consensus standards for the determination of explosibility characteristics. Additional recommendations on the best practices to prevent and/or mitigate explosion hazards are expected. The outcome of this research effort will be a reduction in the risk for gas/dust explosions in the underground workplace through an increased understanding of the causative factors for these events, the development of improved control technologies, and educating the workforce to recognize and prevent explosions.