Study On The Mining Roadway Arrangement And Surrounding Rock Control Technology In Mined-out Area Of Ultra-close Multiple-seams Mining

Many mines in our country, there are different geological exploitationconditions of ultra-close multiple-seams. For ultra-close multiple-seams mining,the downward mining method applied most widely. The state of coal pillar ingoaf and overlying strata have significant impact to the stability of theunderlying seam roadway, and the important means to ensure the stability of theunderlying seam roadway is to choose the reasonable position of roadway andsupporting technology. So the research that on the mining roadway arrangementand surrounding rock control technology in mined-out area of ultra-closemultiple-seams mining has a great significance for the safety and high efficiencyof the coal mine.Based on the coal seam occurrence condition of ultra-close multiple-seamsmining in the second mining area of Jinda coal mine, the structure along thetendency of overlying hard roof strata in the upper No.9coal seam has beenanalyzed. Determine the overlying hard roof strata along the tendency to formstable class masonry beam structure. The stable structure can give a protection to the miningroadway of the underlying seam. Determine the coal pillar inmined-out areais stable through the theoretical calculation. Using the theoreticalcalculation and numerical simulation analysis the stress distribution of floorstrata for stable coal pillar and this provide the basis for the layout of theminingroadwayof underlying seam. Through principal stress change amount tomeasure the stress unbalance degree of coal floor strata. To determine thereasonable position for the miningroadwayof underlying seam is the stressreducing area and the tiny uneven stress area and under the protection of classmasonry beam structure. The reasonable roadway arrangement form of10201mining face is that10201air-return roadway is apart from the border of theupper coal pillar6m;10201transportation roadway s layout is apart from theborder of the upper coal pillar9m and under the goaf of the upper coal seam snext working face; the working face length is170m. On the basis of the analysisof the anchor pile supporting mechanism and the roadway support principleunder the condition of broken surrounding rock in ultra-close multiple-seamsmining, the support pattern in the underlying seam is determined anchor net andI-steel shed throughthe engineering analogy, and the concrete supportingparameters are presented. The monitoring data analysis of roadway surfacedisplacement and anchor pile stress show that the support scheme can takeeffective to ensure the stability and security of roadway.This paper systematically analyzes the determination of the roadwayreasonable position and the selection of supporting technology under the goaf of ultra-close multiple-seams mining, and can provide reference for similarengineering geological conditions.