Design And Research Of Fire Prevention And Extinguishing Scheme For Nitrogen Injection In Goaf Of Fully Mechanized Caving Face In Linnancang Coal Mine

Coal mine fire is one of the major disasters in the mine,coal mine fire will burn a lot of coal resources,the release of a large number of toxic and harmful gases,always threatening the health of mine workers and life safety.According to the statistics of the relevant departments,more than half of the coal mines in China’s coal mines are caused by spontaneous combustion of mined coal.Linnancang warehouse 2220 face with fully mechanized top coal caving technology,the face of coal has a large spontaneous combustion risk.The mine mainly uses injection molding fire prevention technology to prevent coal spontaneous combustion,but the effect is not good.After research to switch to nitrogen fire prevention technology.Therefore,it is of great significance to study the optimal nitrogen injection parameters for controlling coal spontaneous combustion.At the same time,the similar conditions of mine fire prevention work also has theoretical significance.Based on the background of mined-out area of 2220 working face in Linnancang warehouse,The spontaneous combustion tendency of 2220 surface goaf was measured by ZRJ-1 briquette spontaneous combustion tendency tester.The gas spontaneous combustion index is C2H2 by the programmed temperature method,and the minimum spontaneous combustion period is about 30 days.The "oxidation zone" width of goaf was studied by field beam monitoring method and numerical software simulation method.The results of the field measurement are 62 m,the numerical simulation results are 66 m,the simulation results are compared with the measured results,the error range is with in 5%,and the results are basically consistent,which verifies the actual situation of the reconstructed goaf.The results show that the width of the "oxidation zone"is not much greater than the safety width of 45 m under no nitrogen condition,and the control measures need to be taken.The main nitrogen injection parameters of coal spontaneous combustion in mined-out area were obtained by using the model study.The nitrogen injection was 65 m and the nitrogen content was 550 m3/h.At this time,the "oxide band" with is expected to be 43 m.The optimum nitrogen injection parameters were applied to the mined-out area of 2220 working face in Linnan warehouse.The width of the "oxide zone" in the goaf was monitored by the beam tube monitoring system.The results show that after the nitrogen injection,the width of the "oxidation zone" is shortened to 41 m,which is less than the safety width of 45 m.After the nitrogen injection parameters were studied,no spontaneous combustion of coal was carried out in the 2220 working face of the mine,and safe mining was realized.