Research On Determination Of Spontaneous Combustion Three Zones Of Near-Neighbored Coal Seams Complex Goaf In Mei-Yukou Coal Mine

Most of coal seam spontaneous combustion phenomenon in our country, especially with the mature and promotion application of technology of fully mechanized caving coal face, due to its general mining coal seam thickness is larger, after the mining face, into the wind as the roof of roadway and return roadway caving collapse in mined-out area, leading to an internal heritage into the return air roadway position coal mined-out area largely,it easy to contact oxidation temperature and oxygen, cause spontaneous combustion and fire accident.Coal mine is majority groups, rather than individual existence. When one of close distance coal seam group of coal seam mining, the adjacent coal seam mining influence, on the one hand, the original coal seam group of stress balance is broken, lead to stress redistribution within the rock mass of coal seam, coal seam between the formation of a large number of cracks, air leakage complications; On the other hand, when mining the lower coal after affected by the lower coal mining, rock collapse, overlying coal mined-out area but further broken, upper and lower two layers of coal goaf will communicate, form a composite mined-out area. Compound heritage of goaf coal distribution and air leakage of complicated situation with single layer of goaf spontaneous combustion dangerous area have very big difference.In meiyukou coal mine 81004 working face as the research background, from close distance coal seam group mining mined-out area according to the characteristics of nitrogen injection and compound, formed by the compound of goaf spontaneous combustion three zones were divided. First of all, from the 81004 face of close distance coal seam characteristics, combined with the mechanism of coal spontaneous combustion, close coal seam characteristics and actual situation carries on the theoretical analysis of mining face; Then, through the spontaneous combustion test stand, 81004 working face of coal seam coal sample were measured oxygen consumption rate, limit of float coal thickness under different float coal thickness, heat emission intensity and the upper limit of spontaneous combustion characteristic parameters, such as the air leakage intensity and lower oxygen concentration; Finally, according to the related parameters of compound goaf and coal spontaneous combustion characteristic parameters and the related theory knowledge, established the mathematical model of goaf of close distance coal seam composite set related parameters, were simulated under the condition of nitrogen injection and no nitrogen injection compound oxygen concentration contour and goaf air leakage intensity contour map, and connecting with the field measured data, according to the theory of goaf spontaneous combustion dangerous area determination of nitrogen injection and no nitrogen injection under the condition of two kinds of compound mined-out area three zones are studied. By experimental simulation results under the actual situation of the shortest spontaneous combustion period and oxygen heating belt size, calculate the minimum safety advancing speed, 81004 working face in place to ensure that its overlying traces of working face coal spontaneous combustion.