Study On Technology Of Preventing And Extinguishing Fire In Goaf Of Easily Spontaneous And Extra-Thick Coal Seam In Caojiatan Coal Mine Of Yubei

Spontaneous combustion of coal seams is one of the important factors that affect coal mine safety production,and is affected by factors such as mining depth,coal mining methods,roof treatment,and air leakage conditions.In Northwest China,coal was basically formed during the Jurassic period,with the characteristics of low sulfur,low phosphorus,and low ash.It is a high-quality coal resource,accounting for about 40%of the total coal resources in each coal formation period.Spontaneous combustion of Jurassic coal is more serious.To this end,research on fire prevention and fire prevention technology in the Jurassic coal seam goaf of Caojiatan coal mine in Yubei area of northern Shaanxi has been carried out to improve the safety of coal mining,which is of great significance in purifying the environment and protecting resources.Caojiatan coal mine in Yubei belongs to the first phase planning area of Yushen mining area.It is a coal mining enterprise subordinate to Shaanxi coal Yubei coal industry company.The designed production capacity of the mine is 15 million tons per year.There is no goaf around the mine field,which belongs to the well preserved integrated mine field.The 2-2 coal seam is easy to spontaneous combustion and has the risk of spontaneous combustion.The shortest spontaneous combustion period of coal seam is 35 days.The coal seam currently mined in the mine is 2-2 coal seam.The coal seam belongs to extra thick coal seam,with an average thickness of 11m.The mining method of the first mining face of the mine is large mining height and slicing mining.The mining process results in different degrees of coal left in the goaf,especially the amount of coal left at both ends of the heading,so it is difficult to prevent the spontaneous combustion of the left coal in the goaf.prevent the spontaneous combustion of the left coal in the goaf.In this paper,based on the prevention and extinguishing of goaf in caojiatan coal mine,Yubei,through the laboratory determination of spontaneous combustion marker gas and critical value of 2-2 coal seam,study on the law of air leakage in the process of slicing mining with large mining height,determine the three zones of spontaneous combustion in goaf,determine the minimum safe propulsion speed,and make use of the good gas flow characteristics,put forward through the upper and lower corners of the coal face oxygen and oxidation The change rate of carbon reflects the degree of spontaneous combustion of goaf residual coal,and establishes the early warning mechanism of spontaneous combustion.In terms of fire prevention and early warning mechanism,the fire prevention and extinguishing measures such as nitrogen injection,grouting,air leakage blocking and chemical inhibitor spraying are comprehensively established,and the application effect of the measures is analyzed,and the fire prevention and extinguishing system of caojiatan coal mine is studied to guide the safety production.