Revolution Of Mining Pressure And Mining Method Under Irregular Residual Coal Distribuiton

The consumption of coal resources in China is increasing. Therefore, the main point of coalmining is gradually transferring from the shallow resources to the deep. Although the part of theshallow resources had been completely mined, this part coal seam still letf a large amount of coalresources due to the lack of technology and management. Based on a special case of thick coalseam slice mining in which upper layer is mined while lower layer of coal seam was kept integrity,this paper presented a approach to study the situation of occurrence of residual coal and themethod to extract the lower coal seam.Firstly, the mechanical test and TEM instrument wereemployed to master mechanical properties and spatial distribution of scene residual coal.It wasshown that since the inadequate management and particular and complicated of geology at theearly age, residual coal has an extremely irregular distribution.. Therefore, the pressure wasmonitored while mining and an ideal mechanical model was established to evaluate this particularand complicated of geology.The results show that mine pressure changed violently while mining,and pressure value increased rapidly when workface was close to residual coal. The FLAD3Dnumerical model in was established to simulate the irregular distribution in upper layer and masterthe revolution law of stress, displacement and energy at this situation. The numerical resultssuggest thattop coal caving should be firstly consideredand a wide adaptation range of support isalso demanded when mining lower irregular distribution of residual coal. For the issues of thesupport technology, although it has a limited adapt ability, the suspended-beam bracket shouldsatisfy strength demands. Meanwhile, this support should be associated with hydraulic support toachieve better adapt ability to ensure production safety.