| The prevention of gas accumulation in the upper corner is an important measure of gas prevention and control in the working face.The common measures to prevent gas accumulation in the upper corner include set up temporary wind barriers in the upper corner,pressure-equalizing ventilation,high-level drilling drainage,goaf buried pipe drainage,and so on.With the continuous improvement of coal mining mechanization,the gas inflow in working face increases,resulting in the traditional control measures difficult to achieve the desired control effect.The engineering test was applied in Tenghui Mine of Shanxi Province.Taking the Tenghui Mine as the research object,the principles and action mechanism of using large-diameter directional high-level long boreholes to treat the upper corner gas were expounded? According to the theory of three-zone fractures in goaf overburden,combined with the measured data,numerical simulation results,The reasonable borehole diameter is 153 mm,the reasonable extraction negative pressure is 20 about KPa,and the optimal layer of the end of the borehole layout lays in the vertical distance of 60 m from the working face roof.In the process of gas drainage practice,a large number of data were obtained utilizing system monitoring data and manual observation records.The drainage effect and the effect of upper corner gas control were investigated,and the application effect of large diameter directional high position long borehole drainage was evaluated.The results of theory and numerical simulation were verified,and some parameters were revised.This study provides a new method for the gas control of the upper corner in Tenghui Mine and other mines with similar issues.Large diameter directional high-level long boreholes are used to control the gas of the upper corner instead of lanes,which ensures the safety of mine production and saves the cost.It has reference significance for the gas control of other mines. |
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