Safety Depth And Safety Pillar For Backfilling Mining

With the development of mining and deep development,the extensive application of backfilling mining,the existing security pillar delineation there are some limitations,the deep mining safety depth theory proposed for the security pillar delineation to provide a new basis.In this paper,the safety depth of the Sanxin mining area under the condition of filling and mining is studied by using the theoretical analysis,the mathematical model and the numerical simulation method to determine the safety depth as the theoretical basis and the theoretical basis for the mine New method.Mainly completed the following work:(1)Through systematic analysis and analysis of geological data,engineering profiles and production status of Sanxin Coal Mine,the main felling materials were determined in the middle of the Taohuazui-570 m and the technical conditions of the filling,the mechanical properties of the filling material and the ore parameters.According to the law of filling roof dredging,the equivalent thickening model of filling and mining is established,and the equivalent thickening coefficient is 0.2 by using fixed beam theory.(2)Analyze the existence of the safety depth by the law of the rock formation,and apply the safety depth and the moving angle to the wellbore.Analysis of the main factors affecting the depth of safety,filling mining is the most effective and direct way to control the safety depth.(3)The probability mining method is used to invert the critical mining depth based on the equivalent thickening model.The flag of safety depth is proposed as the fault zone,and the height of the rupture zone is obtained from the middle of-570 m in the Taohuazui mining area by using the empirical formula of the cluster theory and the model of the optimal calculation.Critical mining depth combined with the height of the rift zone to determine the middle depth of-570 m mining safety range of-458 m ~-427 m.(4)The numerical simulation method is used to analyze the mining of-470 m ~-420 m in the middle section of the safety pillar,and the rationality of the safety depth is determined before.By analyzing the distribution of the plastic zone during the mining,the change of the roof sinking,the displacement and stress change of the wellbore,To further determine the safety depth range of-442 m ~-438 m.-442 m level below the ore body into the safe mining depth stage to-442 m level for the upper boundary delineation of the lower ore body of the security pillar,can reduce a large number of pressure ore,improve the economic efficiency of the mine.