Study On Gas Drainage Effect In The Gob Of Full-Mechanized Caving Face In Dafosi Coal Mine

The gas emission of fully mechanized caving face mainly come from the high concentrationgas in goaf. The gas extraction in goaf is an important technology measure that can guarantee thesafe production, while the gas seepage law of gob and cover rock is the basic theory to design aneffective gas drainage system. In view of this, firstly caving characteristics of stope cover rockand the hulking properties and pore properties of each areas and terrains should be analysed afterthe coal seam mining, and combining with the actual situation, ascertain the basic parameters ofgoaf, then establish the mathematical model of the gas seepage in goaf in the heterogeneousconditions, and FLUENT is used to establish3d numerical models of gas seepage in the goaf offully mechanized caving face, to study the gas flow field of goaf through the numericalsimulation. This thesis simulates the gas seepage distribution law of gob and cover rock in thethree conditions of the only air leakage, the only extraction of the high level suction roadway andthe simultaneous extraction of high level suction roadway and the upward drainage borehole ofgoaf by using FLUENT.Analysing the results of numerical simulation and learning that, the high concentration gasmigrate to the mouth of extraction under the action of the simultaneous extraction of the highlevel suction roadway and the upward drainage borehole, thus expand the air leakage distance ofgoaf, then dilute the high concentration gas in goaf, block the gas of goaf flocking to workingface. Through the verification to the fully mechanized caving face40104of Dafosi mine，investigating the effect of the high level suction roadway and the upward drainage borehole inthe practical application, thinking the simulation results and practical effects are relativelyanastomotic, namely the high level suction roadway and the upward drainage borehole extract alot of gas, reducing the gas emission quantity of the working face, ensuring the safe productionof the working face...