Critical Medium Column Support Theory And Its Application In The Xilinhot Fluorite Mine

With the gradual exploitation of the shallow mineral resources,the shallow residual mineral and deep mineral resources are gradually put into use,which will lead to more prominent rock movement problems.Therefore,it is urgent to study the new technology of rock movement control to adapt to the changes of mining conditions.This paper takes the Xilinhot fluorite mine as an engineering background.For problems of the large amount of ore in the safety pillar which cause the deep recoverable resources are few,the mining method is not suitable for the ore-rock stability which cause the large ore loss and dilution and poor safety conditions,and the surface rock movement hazard the environment and industrial facilities,the principle of critical medium column support and its influencing factors for mining rock movement are studied,which are used to reasonably release the shaft safety pillar,ensured the stability of the shaft,improved the mining method and controlled the rock movement.The main research results of this thesis are as follows:Firstly,through the investigation of on-site structural plane,point load strength and bulk flow parameter experiment,the basic parameters such as moderate stability of the surrounding rock,unstable of the ore body and easy to cave,and good fluidity of ore granular media are obtained in the Xilinhot fluorite ore.Based on the analysis of the "three-law" characteristics of the mine,the Xilinhot fluorite mine is suitable for medium-deep hole mining technology in roadway operations.Secondly,the lateral pressure variation law of the granular media under static and ore-drawing state is studied through the granular lateral pressure experimental.The quantitative relationship between the passive lateral pressure of the moving granular media and the dip angle,the depth of the bulk and the deformation of the surrounding rock is obtained.Combined with the theory of critical medium column support,the mechanism of the critical medium column of the moving granular media is revealed.Thirdly,the related parameters of the critical medium column are measured in the subsidence area,and the in-depth analysis of the influencing factors of the critical medium column is carried out,the supporting effect of the critical medium column on the safety pillar of the shaft is revealed.Based on this,the optimization method of the shaft safety pillar is proposed,and the numerical simulation analysis of the damage degree of the optimized pillar caused by the mining is carried out,then a new method of shaft stabilization for caving partial top column and total tailings backfilling the goaf in combination with the secondary reinforcement measures for the weak part of the shaft pillar are proposed,which greatly reduces the size of the pillar and also effectively ensures the stability of the shaft.Fourthly,according to the ore body condition and the "three-law" characteristics of the Xilinhot fluorite mine,combined with the mechanism of the critical medium column,the method of recovering the pillar with the high-end wall drawing is proposed.The optimization method of the stope structure parameters and the method of retaining the granular media cushion to prevent the damage of the roof caving are given.Compared with the short-hole shrinkage method,the safe working conditions of the stope are effectively improved,the ore recovery rate is effectively improved,and the depletion rate is reduced.Fifthly,through the on-site surface rock movement monitoring and numerical simulation analysis,the dynamic development mechanism of surface rock movement is revealed,and the rock movement development law and its internal mechanism with the critical medium column are analyzed.The rock movement control method for the coordination of underground goaf treatment and surface collapse pit filling is proposed,and the safe filling method of the collapse pit is given.The method realizes effective control of surface subsidence and rock movement.Based on the study of the mechanism and its influencing factors of the critical medium column of the moving granular media,the proposed shaft safety pillar optimization method,the goaf treatment and shaft stabilization method combined with the caving and filling,the method of the pillar recovery and deep ore body mining with high-end wall drawing conditions and the control method of surface subsidence and rock movement,which have been carried out industrial test and obtained good practical results in the Xilinhot fluorite mine.Theoretical analysis and practical results show that the vertical pillar optimization and surface rock movement control method based on the critical medium column support principle can effectively solve the mining rock movement problem involved in the mining of steeply inclined medium-thickness and unstable ore bodies.It can realize green safe and efficient mining in the Xilinhot fluorite mine.