Damage conduction mechanism and key technologies of damage reduction insources for intensive coal mining in Western China

Scientific understanding of mining damage conduction mechanism is the core issue for safe production in coal mines，aquifer protection and the development of theory on surface appendages damage reduction and key technologies for damage reduction.It is of significance to study the damage conduction mechanism of coal intensive mining in Western China and the key technologies of reducing damage from sources，which is also of significance to coordinate energy demand and ecological protection of mining areas in China.Therefore，considering the characteristics of intensive mining and the characteristics of existing damage reduction technologies，based on the field measurement and simulation of intensive mining in Shendong mining area，the damage law is analyzed，and the damage conduction mechanism of overburden is revealed.The results show that there are some laws of the intensive mining in Shendong mining area such as strong ground pressure behavior，serious overburden damage，severe surface deformation，short movement period，and high development degree of surface cracks.For the first time，it is found that the “basic roof fracture - key stratum fracture-surface main crack” presents a “331” periodic conduction law，and it is concluded that there is a periodic corresponding conduction law between the surface damage and overburden damage of intensive coal mining in western China.This paper reveals the mechanism of overlying rock damage ascending layer by layer and dissipating in different regions，and puts forward the calculation method of mining damage energy and limit damage energy critical value，and establishes the damage JP2dissipation model of different division damage coefficient of overburden “three zones” and mining space，and concludes that reducing damages from sources is the fundamental and effective way to control mining damage.Taking into account the characteristics of intensive mining，focusing on the different purposes of overburden damage control and surface deformation control，the paper puts forward some key technologies of damage reduction from intensive mining sources，including the optimization of mining process parameters，the maintenance of stability of bearing structure of overburden and deformation control to reduce damage，and gives reasonable ranges of mining height，length and advancing speed of working face.The mining optimization of the 12402 working face in the Shangwan Coal Mine is carried out by using this method，and the damage degree and control effect of overburden before and after optimization are compared and analyzed using numerical calculation method.