Numerical Analysis On Combining Mining Of Steep And Close Seam In Jiangou Coal Mine

Coal resource is always the first steadly in energy sources structure for very long time in China .The forecasted coal reserves in Xinjiang are 19241 hundred million tons that is the first in our country, Xinjiang is the region in which storage steep seam concentratedly, there are more than 30 layers steep seams with different thickness and distance, its special storage condition makes it become the attentive focus in mining circles in the world. The scientific mining method of steep and close seam is always the difficult problem in Urumchi diggings. Because mining any coal seam separately always destroys the neighboring ones, the coal seams are only mined 1/2 or 1/3 in some mines, a lot of high quality coal resources are wasted.So studying on high yield and effect mining method of steep and close seam has scientific and economic value Based on the research harvest, using the two and three-dimensions numerical simulation analysis, the law of movement in surrounding rock and the strata pressure appearance are analysed for steep and close seam in Jiangou coal mine using similar material simulation and locale testing experiment, the scientific of combining mining in steep and close seam is studied.Independent mining in steep and close seam can influence the next mining of the adjacent coal seam greatly, either mining from up to down or down to up. To avoiding the mutual influence , combining mining must be used.combining mining not only improve the throughput but although avoid the destroying to the unmined coal seam; when combining mine in the same level(B19 and B20 even B18 ,B19 ,and B20),the mining influent region is more and more increase than indepent mining because of the afresh distribution of stress,but the increasing of the mining region influence it not greatly, this shows that combining mining does not make the scope of destruction and movement in surrounding rock increase greatly,combining mining does not bring unpredictable difficulty to terreance controlling ；the scope of the destruction and movement in surrounding rock causing from horizontal section sub-level caving in steep seam and long wall face sublevel caving in gently inclined seam are very different, after mining coal mass of horizontal section,up the working face of steep seam are remnant and filling coal ,rock and soil mass which takes great effect to the strata pressure appearance that is randomicity. Immediate roof and main roof of the coal seam are also distorted and destroyed in mining , but it only influence the work face near to the roof ,the influnet scope is smaller with the increasing of the obliquity. So to Jiangou coal mine in which obliquity of the coal seam is 84°everagely, the deciding effect to the strata pressure appearance is the remnant and filling coal ,rock and soil mass from the distruction of the terrane up the workface .So the load which bracket supporting is limited,the altitude of the horizontal section can be improved completely in order to increasing the output of the working face.