Construction and Application of Comprehensive Evaluation System of Stope Structural Parameters in Shallow Hole Retaining Method
The reasonable selection of stope structural parameters is particularly important for the shallow hole retaining method with low mechanization and difficult process transformation.To determine the structural parameters of the shallow hole retaining method,a comprehensive evaluation system was proposed,which included the rock mass quality classification,the Mathews stability diagram method,the numerical simulation,and the on-site operability evaluation.Taking a magnetite mine in Bazhong City,Sichuan Province as the engineering background,the Q-system classification method and the modified BQ classification method were selected to provide corresponding parameters support for the Mathews stability diagram method and numerical simulation.Meanwhile,the limit stope structure parameters obtained by Mathews stability diagram method and numerical simulation were evaluated by the time consumption on the processes of scaling roof,leveling field,and ventilation.The results show that when the thickness of the ore body is 15 meters,the limit size of the stope is 15 m × 50 m × 50 m(width×length × height),based on the Mathews stability diagram method and numerical simulation analysis.After evaluating the operability of processes such as scaling roof,leveling field,and ventilation,the limit size of the stope should be 15 m×40 m×50 m.Through practical verification,the stope structural parameters obtained by comprehensive evaluation system can meet the safety and continuity requirements of the shallow hole retaining method,and the economic benefits are significantly improved.