Coal safe and efficient mining theory,technology and equipment innovation practice

In view of the complex and diverse conditions of coal seam in China,the safe and efficient mining technical challenge is analyzed. Based on the stress path effect of different surrounding rock,the six controllable parameters of hydraulic support for surrounding rock stability were found,and the strength,stiffness and stability coupling principle between hydraulic support and surrounding rock were studied. The hydraulic support optimization design method based on “three coupling” principle and the “ top-down” whole optimization method were put forward. For the problems of fully mechanized mining face with super cutting height in thick coal seam,the “cantilever beam+voussoir beam” me- chanical model for roof strata fracture structure was established,and the space condition and mechanical condition for “cantilever beam” were analyzed. The main influence factors for rib failure were analyzed based on numerical simula- tion method,which obtained the sensitivity sort. The anti-impact resistance columns,hydraulic support group coopera- tive control system and “large gradient+small stairs” matching manner were studied,which achieved a safe and effective mining in Jinjitan Coal Mine with 8 m super cutting height in thick coal seam. For the problem of top coal caving property in full-mechanized caving mining face with large mining height,the efficient top coal caving mechanism with three-grade strong disturb function and tail boom impact crushing mechanism were researched. For the problem of nar- row space and difficult to achieve automatic mining,the hydraulic support with super big expansion ratio range of 0． 5-1． 4 m was developed,the normalized remote monitoring and intelligent mining with nobody operating was a- chieved in Huangling Coal Mine. The key techniques of safety and high efficiency extraction were propose,including steady coal cutting and continuous propulsion,high reliability design,extraction equipment robotization and transparent mining.