Application Of Super Large Diameter Borehole And Large Flow Gas Extraction Technology In Goaf In Ma Lan Mine

In the next few decades,the main energy of our country is still coal,and the gas disaster is particularly serious in coal mining.The comprehensive prevention and control of coal mine gas is a very complicated work.The method of large diameter drilling for gas treatment is first proposed at home and abroad.The equipment uses hydraulic cylinder to propelling rotary drilling tools to carry out large diameter drilling.Kong Shigong,after drilling construction,the steel pipe was sent into a large diameter borehole to protect holes by using the drill,and the hole was completed after sealing.The successful research of the equipment has provided equipment support for the research and application of large diameter boreholes instead of connecting tunnels in underground coal mines.Through the construction of large diameter boreholes,large diameter drilling instead of contact lane,large flow and low negative pressure are used to pump gas in the mining face,so that the gas emission in the goaf is large and the upper corner gas is often Overlimited,so as to ensure the safe production of the mine.In this paper,the gas control of the goaf in the 10610 working face of Ma Lan mine of Xishan Coal and electric(Group)Co.,Ltd.is taken as the engineering background.The study of gas in the high flow and low negative pressure extraction in the goaf is carried out by the method of field investigation,theoretical analysis,numerical simulation and field application.In this paper,the law of gas emission in 10610 working face is predicted by the analysis of the mine data and the quantity of gushing.It is calculated that the gas emission of the coal seam and the adjacent layer is 29%,71% respectively,and the gas emission in the lower adjacent layer accounts for 68% of the total gas emission.Therefore,the adjacent layer is the main source of gas emission.Secondly,it comes from the coal seam,and a few parts come from the upper adjacent layer.Then the mathematical model of gas flow in the goaf is set up,and the gas concentration distribution in the goaf of 10610 working face of Ma Lan mine after the drilling of the large diameter borehole is simulated by Fluent numerical simulation software,and the regularity of concentration distribution is obtained.In the end,large diameter boreholes are used to extract gas in goaf.The application results show that super large diameter borehole is used to replace the buried pipe of contact lane and the gas in the goaf is extracted with low negative pressure.The application effect is good in the field investigation,and the gas concentration in the upper corner can be effectively controlled in the safety range and the safety of the working face can be ensured.At the same time,it relieved the tense situation.Large diameter drilling instead of contact roadway buried pipe extraction technology can effectively solve the problem of frequent overlimit of gas in upper corner of high gas mine and gas control in goaf,and can be applied in high gas mine with suitable conditions,providing reference basis and practical experience for all mine gas control in Shanxi Province,and also for National Mine cancellation.New methods and ideas are provided for gas control in dedicated gas drainage tunnels.