Study Of Gas Extraction Methods Of High-methane Coalseam And Its Application In Jixian Coalmine

Firedamp content of JIXIAN coanmine is fairly high and threatened coal production seriously. Gas extraction technique is studied and the blue print of gas extraction in the coalmine is designed. The technique is employed to solve the problem of firdamp and make sure safety production in the mine successfully.Regulation of methane content and its distribution in JIXIAN coalmine are studied. A theoretical model of cranny zone distritution in the gob is set up. The distribution of the cranny zone in above the gob of No.9 coal seam of JIXIAN mine is determined by means of drilling. Gas extraction parameters like angle, direction and length are designed considering the range of the cranny zone. It desighed that the hight of the bore end should be no higher than 3~12m above the bottom of the coal seam and 10~30m away from the coal pillar. The length of the bore is designed to be 120m if the distance between the drilling bases is 40m.The method of gas extraction from the on condition of up-to-down ventilation is determined. The methods of extracting firedamp of the neiboring coalseam withh cross bores, extracting the mining seam gas with fan-shaped boes, extracting the congregated upper corner gas with elevation bores, extracting the gas in the mined out area with pre-burried pipelines, and extracting gas during diging laneway are studied systematically. By combining all the above mentioned methods, firedamp problem is solved well in JIXIAN coalmine.The study is important for directing gas fathering problem in SHUANGYASHAN coal field and also in other coalmines of similar conditions.