Study On Gob Fire Prevention And Control Technology In Goaf Of Y-type Ventilation Coal Face

Currently, Gas drainage from multiple sources with Y-type ventilation is an efficient measure to control gas. And improving the safety of the gas while will reduce the safety of spontaneous combustion; Conversely, reducing the risk of spontaneous combustion that can not meet the requirements of gas management.That will lead to the balance of two security risks. When the gas emitted from the coal face, the main difficulties are preventing and extinguishing the fire. Two kinds of disasters are related and influenced with each other. Therefore, the research of gob fire disaster prevention of goaf on Y-type ventilation system must be strengthened.On the background of the complicated geological conditions of gas control on the surface of the mine 12311 of Pan Yidong, this paper in view of the large amount of gas,but coal mining characteristics, severe air leakage and other projects, starting from the stope flow field distribution rule and gas migration, at the scene investigation,theoretical calculation and numerical simulation, field test and practice, on the basis of Y type ventilation to gas coal seams group face stope comprehensive migration flow field and gas extraction management technology in-depth research, promote the progress of fire prevention technology. The main and innovation points of the thesis have the following four aspects:(1) Flow field distribution and migration regularity of three-dimensional CFD model on slope are established, the mined-out area along the inclined direction, toward the direction, height of Z axis direction of Y type ventilation working face goaf air leakage, oxygen concentration field, wind field distribution of gas concentration field are researched, and determined the distribution regularity of goaf spontaneous combustion area and the three zones. To seek for the focus area of the fire management in the coal seam group with high gas.(2) Based on the mining conditions for 12311 panel of the Y-type ventilation with high gas easy spontaneous combustion, Numerical models are established for analyzing the maximum range of spontaneous combustion, the distance is probably 90 m after entering the goaf, determine the monthly advance rate of not less than 52 m. A large quantity of air leakage is one of the personality traits of gas drainage from different sources with Y-type ventilation, control air leakage have given priority to speed up theprogress of extraction, supplemented by nitrogen injection grouting and plugging the wind method. During mining the 12311 panel, the average advance length per daily is3.6m, and the advance length per month is 112.3m, has been provided the good foundation for the fire preventing and the measures of gas drainage in goaf.(3) Comprehensive coal unloading gas extraction governance measures under the Y type ventilation multi-source extraction conditions have been proposed and implemented. From the 12311 panel of the Y-type ventilation with high gas is easy to spontaneous combustion coal face mining, efforts should be made to increase the high concentration of gas extraction and reduce the low concentration gas extraction on the influence of air leakage of goaf. Among them, the greater influence on the distribution of three zones of spontaneous combustion is mainly for location and tail, we should control the drainage quantity and strengthen monitoring; Ground drilling is need high concentration of gas extraction, the main extraction for 13 coal seam is unloading gas,less influence on the working face goaf air leakage, and it should be developed vigorously;(4) The results of the research are applied to the 12311 panel, the average drainage ratio was 90.47%. the gas drainage techniques(the surface well and bottom drainage roadway) with high concentration and efficiency on the 13 coal seam, average gas average drainage volume exceeded 89.7 m3/min, gas drainage concentration was30%;The highest daily production was 6611 t,the average was 3619.48 t. The total coal production was 1140.2 thousand ton, the total gas drainage volume was 58089.6thousand cubic meters, which achieved mining resources safety and high efficiency.