Research On Stability Of Filling And Intelligent Matching Between Filling And Rock Mass In Deep Mining

Inevitably the future for minerals exploitation is about to involve increasingly deep mining as most of the accessible surface deposits have been exploited. Backfilling method has been widely used in deep mining because of its advantages of controlling ground pressure, reducing dilution rate etc. The filling body design differentiates between deep mining in the presence of highly nonlinear complex environment and shallow exploitation. At present most of the mining designs are conducted by experience analogy method, resulting in unnecessary waste or potentially dangerous mining scenarios. Therefore, it is necessary to carry out investigations on the filling body stability and strength design to secure mining safety in the depth.Relying on the Joint Funding of National Natural Science Foundation (Grant No.51074177) and the Shandong Gold Group and Central South University Cooperation Project (Experimental Study of Cancelling Pillars in the Deep Stope Of Sanshandao Gold Mine), the following researches were perfomed:(1) The mechanical and energy response characteristics of the filling body were investigated during deep mining by which the filling and rock mass coupling mechanics and energy release law were uncovered. And the strength-controlling failure mode and shear-controlling failure mode were established based on different failures of filling body.(2) The reliability theory was employed to analyze the stability of the filling body. The limit state equations for strength controlling failure mode and shear-controlling failure mode were deduced. Because of the complexity of the equations, the neural-network-based Monte Carlo simulation was used for the calcution of reliability index after comparing different calculation methods;(3) Based on the available statistic data of domestic and international metal filling design, the knowledge base model for filling body design was established by using Matlab software taking into account the mining technology conditions, filling technology level, mining methods and filling body stability conditions etc, achieving intelligent matching between filling and rock mass. This can theoretically provide some references for the strength design of filling bodies;(4) According to the practical deep stope in Sanshandao Gold Mine, the reliability of fillings with different proportions was calculated by using intelligent matching model. The filling body strength and the proportion increased exponentially with mining depth changing and displayed a logsit increasing function versus reliability index. When the reliability index was taken as3.2, for553#stope the favorable filling body strength was designed as0.52MPa and the proportion was advised to be1:16. This practice can reduce17.48%of the cost of filling and save2,289,050yuan than the currently being mined stope.