Research On Gas Drainage In Fracture Zone Of Efficient Mining Top-coal Caving Face

For the production of full-mechanized caving mining face release concentration, the gas gush intensity. After the coal seam drainage, in the condition of full-mechanized caving mining and ventilation, the problem of gas outburst concentration is not solved. Therefore, must take account of fissure zone extraction in the enrichment area of mining fissure zone gas.Through separated resources prediction method for the single coal seam to predict the relative and absolute gas emission and according to the regulations of working section and wind speed, ensure absolute gas emission of 29.1 m3/min and total VAM capacity of 58.4m3/min for N2202 working face under the condition of daily output of 6000 t and plan with the wind 4000m3/min.Using UDEC software simulate overlying rock strata dynamic evolution process of fully mechanized working face at the mining height of 6.31 m. Using the masonry beam and the key strata theory calculate the caving zone and fractured zone height of 36.2m and 69 m respectively.Horizontal branch wells drilling can solve concentration of the gas in transitional delamination space of the caving zone and fractured zone. Through multiple regression analysis, determine linear correlation for the distance between km rig drilling horizontal projection and the return air lane and pure of traffic extraction,then calculate the linear correlation equation. By investigating the change of extraction parameters with the change of distance between high drilling field and working face, determine the scope of the stress concentration in front of the working face and damage characteristics of gas extraction drills in the goaf. Through the analysis of efficient extraction horizontal interval for the fissure zone parallel designing drilling in the low drilling field, calculate height range of fissure zone drilling during the efficient extraction of low drilling field. Combined with the statistical t test, statistical analysis of change features on pure traffic of intubation extraction in upper corner, confirm significant linear positive correlation between number of drilling and pure traffic of extraction. The change of azimuthal angle can increase pure traffic of extraction for part of the drilling. By investigating the extraction way of five fissure zone drilling, ensure correlation between design parameter and extraction parameters.Horizontal drilling is obviously effective to gas of concentration in transitional delamination space of the caving zone and fractured zone for the coal seam roof scope of 20m~60m. By investigating the drilling of high drilling field and low drilling field, the lower drilling control horizon, the bigger the borehole inclination is. After fissure zone drilling play a role in extraction, production of full-mechanized caving mining is double, gas concentration is significantly lower in upper corner.