The Gas Overrun Control Technology Research Of Mechanized Mining Face In Xinyuan Coal Mine

In recent years, because of the advantage of high efficiency,security and stability, mechanized mining caving favored by major mining. However, in some high gas or coal and gas outburst mine, gas occurrence content, pouring large and unstable. Face ventilation and gas drainage system keep up,leading to face on the corner gas gauge, this has become a key difficulty in face gas control. Optimizing face ventilation is the most direct and convenient way to prevent gas gauge. But after study we find ventilation just suppress gas gauge and can’t solve the problem fundamentally. So we adopt coalbed roof thousand meters long gas drainage drillings to govern gob gas,which reduce gob gas emission and face gas gauge fundamentally. It has a great significance to guarantee efficient drainage, protection mechanized mining face gas safetyCombined with seam geological conditions, according to the law of fractured evolution, classic rock pressure theory and O-shaped theory, we consider supporting role of goaf four weeks’ coal wall fully, re-divise the goaf to finer zone division:20-30m portion of goaf edge is coal wall support region, form the O-typed fractured region. Formula and Yang hole injection detection method obtain goaf caving zone is 0-18m, fractured zone is 18-50m.Xinyuan Colliery of Yangquan Coal Industry Group is coal and gas outburst mine. The gas content of 3rd coalbed which 3103 face belongs is 14.89 m3/t, the seam permeability is very low. Mechanized mining face transformed into "U+L"-typed ventilation system, but cases of gas gauge still present. Summarizing the advantages and disadvantages of face ventilation systems, research "U+L"-typed and "Y"-typed ventilation finely and propose the new Y-typed ventilation system. By adopting CFD numerical simulation and field data,through analysis we find:For the same wind, optimal air volume ratio is 5: 2,the gas concentration on the corner in the new Y-type ventilation system is between 0.45%-0.68%,and the gas concentration of return wind tunnel is between 0.55%-0.71%, this is better than the "U+L"-typed ventilation system significantly. And the gas concentration of dedicated exhaust tunnel in "U+ L"-typed ventilation is about 3-4%, exceed 2.5% in the "Coal Mine Safety Regulations". The new Y-typed ventilation system guarantee mechanized mining face safety better. However, new Y-typed ventilation still have high concentrations of gas in the goaf, this structs security risks. Therefore, the gas drainage and governance of the goaf is imperative.Combined with the most commonly used slant drilling and hign drainage tunnel gas drainage currently, learn the advantage and add the disadvantage,we adopt coalbed roof thousand meters long gas drainage drillings mearsure. Digging an inclined tunnel from return wind tunnel in mining area 1 to hard steady rock at 35m in the roof. Then setting a high level drill field and hit thousand meters long large diameter bored to extract gas, drillings arranged in 25-45m. Numerical simulation and field data show:The gas drainage concentration of thousand meters long drilling is up to 74%,drainage pure is about 29.4m3/min, The pumping rate of goaf gas reach up to 65.8%; the security situation of face is better than the high pumping drilling tunnel and tilt drillings significantly, on the corner is between 0.38%-0.62%, return tunnel is between 0.449%-0.65%.For one thousand meters face, compared to tilt drillings and high pumping tunnel save money 44,750 yuan and 72,000 yuan. Construction safety fast, long extraction time, once drilled, use in all coal mining. This can even drainage empty the old mining areas after closing goaf.This paper use theoretical analysis, field test, field data and numerical simulation CFD complexly,to demonstrate the face gas overrun govern effect of the new Y-teped ventilation and roof thousand meters long gas drainage drillings. Effectiveness analysis:The new Y-typed ventilation system govern face gas gauge to a certain extent,but it can’t handle high concentrationof gas in the goaf completely. Coalbed roof thousand meters long gas drainage drillings drill gob gas extraction efficiently,it can also guarantee face gas safety. The Final conclusion:Integrated use of roof thousand meters long drillings can govern mechanized mining face gas gauge, complemented by excellent new Y-ventilation system,the gas treatment effect is best. This not only Can reduce the face gas gauge, but also reduce gas emission radically, achieve the best gas control thoroughly. It has a great practical significance for gas prevention and treatment in mechanized mining face of high gas coal mine or coal and gas outburst mine. So it worth spreading ang applying.