Coal burst represented a major hazard for some U.S. mining operations. This paper provides an historical review of the coal burst hazards,identifies the fundamental geological factors associated with these events,and ...Coal burst represented a major hazard for some U.S. mining operations. This paper provides an historical review of the coal burst hazards,identifies the fundamental geological factors associated with these events,and discusses mechanisms that can be used to avoid their occurrences. Coal burst are not common in most underground mines. Their occurrence almost always has such dramatic consequences to a mining operation that changes in practice are required. Fundamental factors influencing coal burst events include strong strata,abnormal strata caving,elevated stresses,critical size pillars and the lack of sufficiently sized barrier pillars during extraction. These factors interact to produce excessive stress,seismic shock and loss of confinement mechanisms. Over the 90 years of dealing with these hazards,many novel prevention controls have been developed including novel mine designs and extraction sequences,most of which are site specific in their application. Without an accurate assessment of the fundamental factors that influence coal burst and knowledge of their mechanisms of occurrence,control techniques may be misapplied and risk inadequately mitigated.展开更多
The origins and main control methods of gas in coal seams were introduced cursorily, and the processes that need to be done in controlling gas, which includes prediction of gas emissions, drainage systems, the means o...The origins and main control methods of gas in coal seams were introduced cursorily, and the processes that need to be done in controlling gas, which includes prediction of gas emissions, drainage systems, the means of prevention of gas outbursts, and some suggestions were put forward. The characteristic of different gas emissions and the corresponding counter measures were presented, and ＆ case study of simultaneous extraction of coal and gas in Xieyi Coal Mine was carried out by coal mining and gas extraction without coal-pillar. The field application shows that gas drainage ratio in panel 5121（0） averages about 90% and reaches as high as 95~/0, which will give beneficial references to gas control in coal mines.展开更多
This paper will review three broad types of political implications of emergency management, since historically emergency management was considered only a function of law enforcement and fire departments, with the supp...This paper will review three broad types of political implications of emergency management, since historically emergency management was considered only a function of law enforcement and fire departments, with the support in the event of a major catastrophe from public health and civil defense organizations. The issue is not whether governments will be required to respond to emergencies but rather when and how frequently. The time to think about emergencies is before they happen. Despite some significant weakness in the overall approach, political implications offer many benefits and provide various options for CDCs （community development corporations） to get involved in disaster recovery and emergency management. Based upon a generally positive evaluation, the paper concludes that emergency management must become a central activity, whether at the federal, state, or local or as an intergovernmental activity. Hopefully for the future the government does not have to wait for a disaster to strike for one to put a policy into place, since they have had several to occur over decades. The government should be ready to take on any disaster if it occurs with the following policies and procedures that are in place.展开更多
文摘Coal burst represented a major hazard for some U.S. mining operations. This paper provides an historical review of the coal burst hazards,identifies the fundamental geological factors associated with these events,and discusses mechanisms that can be used to avoid their occurrences. Coal burst are not common in most underground mines. Their occurrence almost always has such dramatic consequences to a mining operation that changes in practice are required. Fundamental factors influencing coal burst events include strong strata,abnormal strata caving,elevated stresses,critical size pillars and the lack of sufficiently sized barrier pillars during extraction. These factors interact to produce excessive stress,seismic shock and loss of confinement mechanisms. Over the 90 years of dealing with these hazards,many novel prevention controls have been developed including novel mine designs and extraction sequences,most of which are site specific in their application. Without an accurate assessment of the fundamental factors that influence coal burst and knowledge of their mechanisms of occurrence,control techniques may be misapplied and risk inadequately mitigated.
文摘The origins and main control methods of gas in coal seams were introduced cursorily, and the processes that need to be done in controlling gas, which includes prediction of gas emissions, drainage systems, the means of prevention of gas outbursts, and some suggestions were put forward. The characteristic of different gas emissions and the corresponding counter measures were presented, and ＆ case study of simultaneous extraction of coal and gas in Xieyi Coal Mine was carried out by coal mining and gas extraction without coal-pillar. The field application shows that gas drainage ratio in panel 5121（0） averages about 90% and reaches as high as 95~/0, which will give beneficial references to gas control in coal mines.
文摘This paper will review three broad types of political implications of emergency management, since historically emergency management was considered only a function of law enforcement and fire departments, with the support in the event of a major catastrophe from public health and civil defense organizations. The issue is not whether governments will be required to respond to emergencies but rather when and how frequently. The time to think about emergencies is before they happen. Despite some significant weakness in the overall approach, political implications offer many benefits and provide various options for CDCs （community development corporations） to get involved in disaster recovery and emergency management. Based upon a generally positive evaluation, the paper concludes that emergency management must become a central activity, whether at the federal, state, or local or as an intergovernmental activity. Hopefully for the future the government does not have to wait for a disaster to strike for one to put a policy into place, since they have had several to occur over decades. The government should be ready to take on any disaster if it occurs with the following policies and procedures that are in place.
