Design And Application Of Mining Method In 82° Steep Seam Of Zhenggao Coal Mine

With the continuous strengthening of coal mining intensity in the southern region,the ratio of coal production in steeply inclined coal seams to total output in the southwest region has increased year by year.How to mine high steep coal in the southern region safely,efficiently and greenly has become an urgent problem for the electricity-coal mine supply of the southwest region and the sustainable development of the coal industry.Based on the complicated geological conditions and the largely inclined coal seem(inclination angle=82°)of the zhenggao coal mine,as well as the comparatively lagging social,economic and technology positions in this region,the influences of each factor,such as inclination of coal seam,thickness of coal seam,geological tectonics,conditions of roof,economic benefits and social benefits,were all comprehensively analyzed.It put forwards that the adoptive methods for the 82%inclined coal seam of the Zhenggao Coal Mine might be step mining method,segmented pillar mining method,flexible shield support mining method and mechanized mining method,etc.Based on the geological conditions and the production technical conditions,the hierarchical structure model was applied to determine the mining method.The weights of production technical conditions,economic benefits,social benefits were 0.571,0.268 and 0.143,respectively.And the inclination angle,the thickness of coal seam,the geological condition,the characteristic of roof and floor,the production and efficiency,the investment,the safety and the labour intensity were 0.133?0.2?0.4?0.267?0.6?0.4?0.75 and 0.25,respectively.Taking this as the basis,the membership degrees of the step mining method,segmented dense pillar mining method,flexible shield support mining method and mechanized mining method were 0.48?0.57?0.63 ? 0.60,respectively.And the results showed that the flexible shield support mining method was the most suitable method,and the following methods were the mechanized mining method,the sectional dense pillar mining method,and the bench mining method.The most suitable method for Zhenggao 82° high steep coal seam mine was the flexible shield support mining method.The particle flow(PFC2D)numerical simulation software was used for the flexible shield support in the Zhenggao coal mine to analyze and study the coal mining characteristics of Characteristics of coal mining,crack development of surrounding rock,evolution characteristics of surrounding rock force chain,When the oblique angle of working face are 54°?59° and 65°,respectively.The analysis and comparison show that the 59° oblique angle should be a more suitable oblique angle for the working face of the flexible shield support in the Zhenggao coal mine.Based on this,combining the analysis results from analytic hierarchy and the fuzzy comprehensive evaluation method,the flexible shield support mining method was chosen for Zhenggao mine for the 82° coal seam.The mining method and mining parameters,including working face layout,support layout,roadway support and mining technology were designed for the minging face 16604 in Zhenggao Coal Mine.By engineering practice,it was demonstrated that the flexible shield support mining method was very suitable in steep coal seam mine in southwest China,which not only improve the production efficiency,but also improve the safe condition,the labour intensity as well as the economic and social benefits.At present,the flexible shield support mining method has been used in other work faces and neighboring mines,which has improve the technical level in other mines.And the next step for the 82° steep coal mine,the mechanized cutting method and semi-automatic shifting method will be developed to improve the mining scale and the mining efficiency of coal mine in Liupanshui region.