Research Of Preventing And Extinguishing Fire Technology In Isolated Island Goaf

With the improvement of the mine mechanization and the acceleration of mining velocity, the area of the goaf is expanding and the residual coal is increasing. As a result, the hidden dangers of the spontaneous combustion of coal in goaf become more prominent. Around the isolated island goaf, the coal pillars between the three coal-faces are small. So the mining would inevitably cause a large number of fissures in the pillars, or even make the pillars pressured crisp. Then, connected with the isolated island goaf, the fissures would form a channel of air leakage. In a certain period, the crossheadings on both sides of the isolated island goaf are in the states of inlet air and return air respectively, which brings greater pressure between the ends of the channel of air leakage and generates more air leakage. If the technical measures are not undertaken earnestly or the fire dangers are neglected, there would be an occurrence of spontaneous combustion of coal, which threatens the safety of the mine production seriously.The 4110 isolated island goaf, which lies in the Liangjia Mine of Longkou Mining Bureau, is defined as the study object. From the mechanism of the spontaneous combustion of coal as the start, the paper gives out an analysis about the causes and characteristics of the spontaneous combustion of coal in isolated island goaf, helping further understand the environment of the spontaneous combustion of coal in isolated island goaf. Through observing and calculating the thickness of the float coal in goafs, the porosity of the loose coal, the intensity of air leakage in goafs and the original temperature of the surrounding rocks, the author makes the quantitative assessment to the risk of the spontaneous combustion. In order to make the early prediction of the spontaneous combustion of coal better and determine the gas index which could identify the spontaneous combustion of coal, the paper chooses to do certain experiments on the coal samples of and then propose the marked gas index that could identify the spontaneous combustion of coal in Liangjia Mine. The experiments are the ones that could reveal the disciplines of the spontaneous combustion of coal, involving the ones both in constant and mutative air volumes under the temperature of 35℃, the ones under the temperature of 70℃, and the ones under the heating conditions.For the study of the disciplines of air leakage in the isolated island goaf, the paper do certain experiments and researches on the 4110 isolated island goaf by adopting the technology of SF₆ mensuration for air leakage. It also makes a numerical simulation to the state of the air leakage in goafs by the fluid simulation software. According to the actual state of air leakage in isolated island goaf, the paper proposes a comprehensive planning for fire prevention, which mainly uses the pressure-balance technology to balance the pressures at both ends of the air leakage channel, so as to eliminate or reduce the air leakage, supplemented by plugging with the MEA materials and temperature detection. Through the planning we achieve a good application effect.