Research On The Layout Of Mining Laneway And The Ventilation Corridor's Prevention In The Downward Mining Process Of The Group Of The Close Distance Coal Seam Easy To Burn

The group of the close distance coal seam is widely distributed in our country with taking downward mining as major mining sequence in a great amount.With small interval between coal seam and big mining influence within coal seam,the overlying strata structure is affected by multiple mining activities and the crack develops with a high degree and big destructive scale.That takes large difficulty to the prevention and domination on the stability of surrounding rocks on the working surface,the gas disasters,water disasters and fire disasters.Therefore,it plays an important guiding role on the safe and efficient mining to study the reasonable layout of mining laneway and the control technology of ventilation corridor in the goaf in the downward mining process of the group of the close distance coal seam which is easy to burn.Taking the group of the close distance coal seam as research object,this paper synthetically uses the research method of laboratory testing,theoretical analysis,computer simulation and engineering practice on the spot.This paper also take a comprehensive study on the layout of mining laneway and the key technology of ventilation corridor's prevention in the downward mining process of the close distance coal seam which is easy to burn.(1)The research tested the natural characteristic parameter of the main coal seam in Nantun Coal Mine and determined the spontaneous burning type of the coal seam.This research also discussed and studied the development and evolution of surrounding rock fracture development growth rule of the top and bottom floor after the coal seam mining in the upper and lower coal seams.According to the change of the air seepage and seepage coefficient in the goaf,the research analyzed characteristics of regional distribution of the goaf porosity space formed after mining the upper coal.By the synthetic analysis of crack channel and the regional characteristics of the goaf porosity space,the spontaneous burning area in the upper coal goaf was effectively divided,which provided the basis on the reasonable layout of mining roadway in the lower coal seam.(2)The theory studied the distribution law of floor stress caused by mining in the upper coal and established the stress propagation mechanics model of coal floor.It deduced the distribution function of the vertical support pressure and horizontal support pressure and obtained a theoretical calculation formula of reasonable layout of mining roadway in the lower coal seam.This theory was combined with the rational division of the spontaneous burning area in the upper coal goat,and eventually found a method for determining the reasonable position of the mining roadway under the goaf of close distance coal seam.(3)According to the evolution rule of crack corridors mined from close distance coal seam and the prevention requirement of air leakage,this paper proposed a truss anchor cable reinforcement support scheme for roadway surrounding rock in the crack area and designed reasonable closed control measures of crack corridors.This paper analyzes the mechanism of support and control crack development of truss anchor cable and optimizes the design of supporting scheme parameters.(4)By using the above theory and numerical simulation,this paper determined the mining parameters of close distance coal seam in Nantun Coal Mine.And by taking some industrial test,this paper verified the rationality of the location of the coal roadway and the accuracy of the spontaneous burning hazard area in the upper.With the effective reinforcement scheme,the integrity of the surrounding rock is extremely kept and the cracks of goaf air leakage are effectively controlled.There are any disasters of spontaneous burning of air leakage,which ensures the efficient safety of mining in the close distance coal seam.