Study And Application Of Hydraulic Punching Of The Coal Seam二₁at Fangshan Mine

The technique about the role of hydraulic punching in permeability-improvement at mining without protective layer was studied in this paper. The principle of the technology,mechanism of action and effects were investigated with the method of theoretical analysis combining with field trials based on in-depth understanding of the progress in related areas of the research.In allusion to the coal seam at Fangshan mine,whose coal is soft and permeability is low,in order to achive the rapid, safe and efficient excavation in the coal seams with serious gas outburst potential, by the method of combination of theoretical analysis and field test, the theory of pressure relief and permeability improvement by hydraulic flushing was analysised, suitable technique parameters and process of hydraulic flushing for Fangshan mining area was determined. Since the implementation of hydraulic flushing,we got a gas pumping rate of61.65%within the control range,influence,we got a influence radius of1.5m～2.2m by the means of gas pressure and gas flow,we compared the gas basic parameters such as the permeability of the coal seam pre-and-post hydraulic flushing,.the result show that the permeability coefficient of experimental coal seam has approximately increased by50-fold.These fully demonstrate the validity and reliability of the hydraulic flushing,has provided a powerful guarantee for the efficient and safety production of coal mine.