Study On Gas Extraction Technology Of Goaf With High-position Drilling In Xiaoqing Mine

Gas extraction is the most fundamental means preventing and controlling gas.It is the important guarantee to realize safe production of coal mine.In order to make the production more reasonable and more efficient,this paper should further study characteristics in the extraction of mining,including corresponding evolution laws of strata structure after mining and migration characteristics of pressure relief gas during the mining of coal seam.It had an important practical significance for preventing the gas accidents,improving production conditions,and improving the economic benefits to study on high drilling goaf gas extraction technology to prevent the influence of gas emission in production safety of coal mine.This paper deeply analyzed the basic theory of gas,mastered the gas migration rule of goaf from the gas composition,physical properties,occurrence state of gas in the coal seam and its source.According to the lithology and mechanical properties of mining stope's overburden,the finite element model was established.Through numerical simulation,the destroyed and migration rule of roof strata was concluded.It determined the movement rule of the mining strata"O" ring on the working plane.Based on CFD technology,goaf gas migration was numerically calculated.It concluded that the gas accumulation along the return air side formed enrichment zone.At the same time,the concentration presented a trend of increasing along the direction of upper corner.This paper took Xiaoqing mine for an example,according to geological conditions and mining intensity of various mining face,under the geological conditions of Xiaoqing mine,The range of the "effective extraction fissure zone,and "the coal wall support influence area"was concluded.It used oblique borehole extraction from the roof,roof level long borehole extraction technology and goaf gas extraction shaft gas extraction,combining the actual situation to optimize related drilling parameters layout,construction technology,construction equipment and optimized extraction system.This paper had obtained the good effect of extraction by using high drilling goaf gas extraction technology in the practical application of Xiaoqing mine.The extraction of ground vertical holes in the mining face had the best effect,It made the extraction of gas concentration be higher,the amount of gas extraction with a long cycle be relatively stable,drilling services be longer,management be more convenient and play a good role in energy conservation and emissions reduction.It provided reference for the coal working face gas management in the future.And it had a broad prospect of popularization and application.