Gas Distribution Of The Upper Gob Of Close Inflammable Goal Seams Mining

Close distance coal seam, usually think coal layer upon layer spacing is very close, when mining coal seam with significant influence each other. In recent years, along with the accelerated process of industrialization, coal as main energy consumption increasing, our country each big upper coal seam have been exhausted and sequential into deep mining, more in deep mining is close distance coal seam mining. Close distance coal seam mining face more than the single coal seam mining more complex problems. Modern coal mining technology of roof management generally all caving method is used, the upper cover due to the close distance coal seam mining process of coal seam mining is destructive of layered roof, not only to the slicing of roof management increased the difficulty, also makes the layered roof caving, the overlying coal seam with caving goaf, roof, make up and goaf unicom causing air leakage support environment, For easy spontaneous combustion of coal seam itself has the spontaneous combustion tendency of coal seam, close distance coal seam mining upper left in the goaf float coal and has a certain thickness, when gathered to heritage coal spontaneous combustion in goaf is caused when the calories heritage of coal spontaneous combustion in goaf, and brings a great threat to miner life safety and coal mine property. Research process of close distance coal seam group mining the upper coal seam and the rules of coal spontaneous combustion in goaf float and comprehensive prevention and control technology is of great significance to prevent mine fire accident.PINGSHUO Underground Coal Mine No.9coal seam belongs to the spontaneous combustion of coal seam has been emptied, thick3.05～19.46m, the average thickness of12.51m,11coal seam belongs to the spontaneous combustion of coal seam thickness of0.95～0.95m, average thickness of4.7m,9#of11#coal seam and the overlying coal layer upon layer spacing with an average of7.78m.In this paper,9and11coal seam spontaneous combustion of coal seam features comprehensive test experiment, the CFD (Computational Fluid Dynamics, Computational Fluid Dynamics) simulation of goaf gas distribution law research, downhole drilling tube monitoring of1103working face under goaf gas concentration and distribution and tube monitoring1103face this index of coal goaf gas concentration distribution and get the following conclusion:1.PINGSHUO Underground Mine on the9th, the11th of coal spontaneous combustion characteristics of the basic parameters for the Volatile high (greater than18%), coal porosity larger, higher total sulfur in coal, coal rock components vitrinite set higher, both spontaneous combustion coal seam.2.Draw comprehensive judgment Gobs spontaneous combustion of coal gas targets by two PINGSHUO underground mine on the9th, the11th experimental study of coal sample spontaneous combustion characteristics, namely the observed changes in pre-concentration of CO gas C2H4and C2H2occur in combination and concentration of comprehensive as Gobs of coal spontaneous combustion and criteria for judging the degree of combustion trends. CO has begun to appear oxidized coal samples indicate if detected appeared C2H4, indicates that coal has entered a phase of accelerated oxidation from the heat, the description appears C2H2gas has left the coal combustion.3.By using CFD simulations PINGSHUO Underground Coal Mine No.11,1103covering the work surface goaf gas distribution, come1103the Ministry of the working surface oxygen concentration Gob face at a distance of1103after0m-40m high reach5%-10%, after1103face40m-250m away from the oxygen concentration of3%-5%from1103after face after250m oxygen concentration decreased to below3%,1103Ministry Gob work surface work in1103when the front side in addition to a very narrow transition zone the concentration of oxygen in the oxygen of3%or less.4.Through the next two PINGSHUO underground mine drilling embedded beam tube, monitored the1103mining work surface overlying gas concentration and distribution of empty areas and simulate the11th seam work surface covered with CFD1103goaf gas distribution the relative ratio of the simulation results are in good agreement with the actual situation, to verify the accuracy of the results. By goaf gas distribution derived work surface PINGSHUO1103 Underground Mine Gob is not currently cover a large area of coal spontaneous combustion.5.By PINGSHUO Underground Mine No.11,1103goaf coal seam gas distribution division of the1103goaf danger zone range, that Gob Thermal Tape range is0-40m, with a40m-oxidation250m, suffocate with greater than250m.1103face a minimum advance degree1.76m/d.In this paper, two PINGSHUO underground mine on the9th, the11th Experimental study of spontaneous combustion of coal samples obtained on the9th of coal,11coal spontaneous combustion index gas, mining overlying air zone downhole gas concentration monitoring beam tube11coal mining face in1103and distribution, combined with the numerical simulation prediction Gobs overlying coal spontaneous combustion. The results of this paper overlying mining research when layered under Seams Spontaneous Combustion instructive.