Study On Optimization Of High Level Drainage Technology On Top Slice Coal Face In Hebi No.6Coal Mine

This paper systematically study the gas in the high level drilling field drainagegob of the coal mining face of mine’s top stratification, focusing on the features ofrapidly discharging gas and easily causing accidents in gas outburst mine of China.Numerical analysis software is employed to simulate the overlying formation’smovement rule and the scale of the gas distribution upon the gob. Plus, theoptimization of the high level drilling field’s parameters is proposed by the light of thetheory analysis, which enhances gas drainage efficiency and ensures the safety andhigh-efficiency in mining.This paper consists of theory analysis, empirical formula computation, numericalsimulation, and site inspection and application effect of the investigation. First, basingon the previous studies, theory analyses are applied to the deformation and zoning ofthe overlying formation; second, empirical formulas are adopted to compute to theheight of caved and fractured zones. Third, the scale of the height and gas distributionare simulated by the RFPA2D; Fourth, the results of empirical formulas are combinedwith the simulation to analysis the test drilling field, and the effect of gas drainage isinvestigated on site. Meanwhile, the distance between drilling field and work face andthe influence of the borehole end scope are studied, determining the reasonableposition of the high level drilling field and the sealing depth of the borehole. Theparameters of the drilling field and drainage borehole are optimized; Fifth, theoptimization effects are investigated on site, which is correlated with theory analysis,empirical formula and numerical simulation.The onsite investigation shows that the single pore’s gas drainage value reachedup to2.15m~3/min, and the mean value reached to8.47m~3/min, which means that thismethod is effective for addressing the gas. The results of this paper provide importantpractical experience as well as theoretical and technical supports for the gas control ofthe gob utilizing the high level drilling field.