Study On Stability Of Pillar In Isolation Layer During Transition Stope From Filling Succeed Caving Method In Jinshandian Iron Mine

Filling succeed caving mining method is in favor of environmental protection in mining areas and removing a hidden danger from capacity of tailings reservoir is made an urgent request for help in an emergency. To ensure a smoothly succeeding under caving mining method, isolate pillar should be established between the transition section of filling succeed caving mining method, and ascertain the optimal critical safety thickness of isolate pillar as insurance for stability in transition section and the stope below transition section, it is a key to solve the problem about securely succeed of mining method. Therefore, it is an important realistic significance to study on stability of pillar in isolation layer during transition stope from caving method to filling method in Jinshandian iron mine.This paper is based on the engineering background of Jinshandian iron mine in Daye of Hubei Province, physical testing, theoretical analysis, engineering analogy and numerical simulation has been taken to study on stability of pillar in isolation layer during transition stope from filling succeed caving mining method. The main contents are as follows:(1) To begin with field research and information collected, preliminary analyze mining status of mine and the features of ore-rock properties in stope; with the result of the mechanic test, to evaluate mechanical parameters of ore-rock mass; combined with the practical stoping, main factors affecting to isolate pillar stability has been concluded, namely, the thickness of isolate pillar H, goaf span B, width of spacer pillar below isolate pillar W, and the property of filling body.(2) Introduce theoretical analysis method to determine the parameters concern stability of isolation pillar. Integrated analysis implied that the theoretical value of reasonable parameters in stope in relation to isolation pillar as follows: goaf span B is between 8~12m, the thickness of isolate pillar H between 10~16m.(3) Build on the theoretical analysis results, FLAC3 D has been applied to establish three dimensional numerical model of two processes on ore room stoping and goaf filling below the isolate pillar to make numerical simulation, change regularity of displacement, stress, plastic range have been analyzed. Combining with theoretical analysis and numerical simulation, the effect factor to isolate pillar stability on least security coping thickness H is 14 m, goaf span B is 8m, width of spacer pillar is 10 m.By studying on stability of pillar in isolation layer during transition stope from filling succeed caving mining method in Jinshandian iron mine, the optimal critical parameters from isolation pillar and its stope concerned are determined, provide a considerable technical support for mine production.