Study On Safe Mining Technology Of Three Empty Irregular Island Working Face In Qiuci Mine

Island working face mining is of great significance to improve mine production,but its mining safety has always been a matter of concern.Aiming at the special island face and considering the safe mining of high recovery rate,this thesis takes the A503three-face empty irregular island working face of Qiuci Coal Mine as the research object.The mechanical properties of coal seam are analyzed by means of laboratory test,theoretical analysis,numerical simulation and field measurement.The mining design method of irregular working face is put forward,and the strength of coal pillars with different aspect ratios is checked.The excavation,support and mining technology of irregular island face are designed.The influence of advance distance and surface length on the mining pressure behavior of three-face empty irregular working face is studied.The characteristics of mine pressure behavior and engineering practice effect of A503 irregular island working face are measured and analyzed.The main results were :(1)Based on the characteristics of the mining area of the A503 working face in Qiuci Mine,four working face layout forms of " general,sawtooth,convex characters and tool handles" were designed and compared,and the mining method of irregular island working face characterized by " expanding(shrinking)with mining " is determined.The " four zones " of A503 working face are designed : "invariant zone" → "expanding zone" → "invariant zone" → "shrinking zone".The strength of coal pillar(height-width ratio of 0.3,0.4,0.6,1.2)was checked,and the ultimate strength of coal pillars was 21.71,18.17,14.63,11.09 MPa,respectively.(2)Combined with the actual situation of A503 irregular island working face,the excavation and support scheme of the working face is determined.A mining technology of "extremely irregular" isolated island face with rapid and continuous increase and decrease of support is proposed.(3)The influence of different advance distance and surface length on the law of mine pressure behavior in irregular island working face is studied.The mine pressure monitoring scheme of A503 fully mechanized caving face is designed.The characteristics of mine pressure in the working face during the expansion and contraction of the working face and the mining roadway are analyzed,and the safe mining effect of the irregular island surface is verified.The thesis has 87 figures,24 tables,and 83 references.