Mechanism and controlling technology of rib spalling in mining face with large cutting height passing through fault

Rib falling becomes a main problem at mining face with large cutting height under high-intensive extraction and even leads to the stop of a mining operation. Numerical simulation, theoretical analysis, laboratory test and in-situ monitoring were carried out for improving the stability of coal wall as working face approaching fault and the mechanism of rib falling. Also, the influential factors and their control technologies were analyzed. Expansion of plastic area magnified the damage degree of coal before its exposure to fault, which might cause accident. Mechanical model for stability analysis was built, and the criterion of shear and tensile rib falling were put forward respectively. Formula used for calculating crack angle was deduced for the first time, then its influential factors were analyzed. The impacting extent to shear and tensile rib falling of different factors were cohesion>mining height>friction. The frequency and hazard degree of rib fall increase near the fault because of its large mining height, the deduction of coal physical and mechanical properties and the increase of roof load. In the study, the controlling measures of small cutting height, high setting force, large coal wall protection height with heavy equipments and grouting were applied at 8101 mining face in Wangzhuang Coal Mine and the in-situ measurement showed a good effect. ©, 2015, China Coal Society. All right reserved.