According to Datong "dual hard" full-mechanized caving mining conditions,the practice of fire prevention and extinguishment technology by optimizing the ventilation systems,balancing gas pressure,spraying frog in working face,injecting nitrogen into coal seam,and grouting into gob in full-mechanized caving mining face was discussed.

This paper analyzes on the reasons of the self-ignition in the fourth and the ninth coal beds in Ningwu Coalfield,expounds the main advantages of the technology of fire prevention and extinction by nitrogen injection,and discusses the effects of the technology of fire prevention and extinction by nitrogen injection.

The application of impulse fine dry powder fire extinguishing technology to the building fire protection design;