Several scientific issues on major thermodynamic disasters in coal mines

Statistics of major coal mine accidents in China show that thermodynamic disasters (fires and explosions) account for the highest proportion and cause the most serious damages.However,the causes,effects and relief risks of thermodynamic disasters are still insufficiently understood.As a result,there is still a lack of effective methods and techniques for the prevention and treatment of major thermodynamic disasters,causing serious thermodynamic accidents to occur from time to time.If it happens,rescue and treatment work often face difficulties.Aiming at the urgent need to prevent and contain the major thermodynamic disasters,three key scientific issues that need to be resolved are proposed by the systematic statistical analysis of cases around the world,the summary of first-hand accident rescue experience,and long-term intensive research.They are the ignition and combustion characteristics of gas-solid composite combustibles (gas and coal) in the stope,the coupling hazardous effect of disaster-causing factors (shock wave and smoke) and ventilation systems,uncertain risk and response during disaster rescue and treatment.A comprehensive explanation and analysis of their research status,development trends and prospects are also carried out.In order to solve these scientific problems,it is necessary to strengthen and improve the gas drainage and roof control technology,prevent the mixing of gas and air,reduce and control the piezoelectric effect caused by the periodic roof weighting,and eliminate the initial ignition source of the combustion or explosion of gas,which will improve the disaster prevention capability of the mine.Understanding the law and degree of the spread of shock waves and smoke flow in the ventilation system,constructing a reliable ventilation system and effective avoidance system are also important for improving the disaster reduction capability of the mine.Developing technologies to discover and deal with uncertain risks can improve the mines’ disaster relief capabilities.The solution of these scientific issues will break through the existing technical bottlenecks,improve the ability to prevent the formation and expanding of the thermodynamic disasters,as well as the respond to uncertain risks.It is of great significance to provide key scientific basis for the healthy and sustainable development of coal industry in China.