Study On Reasonable Length Of Mining Area And Parameter Of Pillar Of Nanliang Coal Mine With The Partitional Coal Mining

Mining practice of the ShenFu mining area near 20 year indicate that pressure appearance for shallow coal bed with thick loose sand and thin bedrock is intense. Cut falls of overburden will occur along the working face, Step sink of the surface will present . To guarantee safe mining, the small mine pit have used the room column type method of exploitation, this needs not only to remain a large number of coal pillar,but forme hundreds of thousands of square meters worked-out sections. After the coal pillar loses the support ability gradually, the roof can have big area fall, and forms a strong vibration that Causes serious harm to the mine.NanLiang coal mine 20105 working faces are first experimental face of the partitional mining method. According to field observation to 2 kind of different advancement length's working face, rule of strata pressure is summarized under condition of shallow coal bed , as well as the the rule of cracks perforated full overburden. Observation for experiments working face indicates that advance distance of 50m is safe, but distance of more than 50m has the latent danger, specially the working face cracks perforating surface and full overburden cuting fall have great harm. 20105 working face experiments has presented this kind of harm. The parameter design of partitional mining method must avoid this kind of disaster.In view of the partitional mining method of NanLiang coal mine, the concepts of the temporary coal pillar and the isolation coal pillar are introduced. Two different arrangement ways are proposed to avoid the big area falling disaster. This article confirmes stress distribution reliability of temporary coal pillar and the isolation coal pillar studied, and proves that the 15m isolation coal pillar is reasonable. The survey indicated that ground has already caved in partitional mining method of NanLiang coal mine and realized roof small area falls without disaster. Through the coMParison of partitional mining method and the knife column method of exploitation, Superiority of the partitional mining method applicated to the middle and small scale coal mine has analyzed.Numerical simulation of the temporary coal pillar and the isolation coal pillar are carried using the FLAC3D procedure. Theoretical analysis and the numerical simulation indicate that scheme arrangement of temporary coal pillar in width 5m and isolation coal pillar in width 15m can realize roof small area falls without the disaster. The roof big area falls disaster appeared frequently in small coal mine have been prevented. This are consistent to the conclusions obtained by other studies...