Optimization Of Deep Stope Structure Parameters And Mining Sequence

In the field of mining science, it is of important significance for the stope structure parameter and mining sequence to study rock mass mechanics. The previus works usually depended on the empirical method or the semi-empirical one, as a result, the potential risk is hard to be found. What is more, with an increase in the mining depth, the high ground pressure resulted from unreasonable stope structure and mining sequence is more and more obvious, and more and more resource will be wasted.This work is supported by the project"Optimization of Stope Structure Parameters and Mining Sequence in Deep Mining Engineering"from najing qixiashan deposit. According to the on-site geological field investigations and reference of the similar project, the research on the deep stope structure and mining sequence in huzhuashan NO.1 lode had been made by using the numerical simulation method. The main works are summarized as follows:①Based on the geological condition and the on-site mining investigation, the mechanical properties of rocks have been measured, and the rock mass have been evaluated by using RMR classification method which takes factors of uniaxial compressive strength of rock,RQD,joint spacing,joint condition,ground water and the adverse special array of joints into account. The rationable and reliable parameters of rock mass are determined based on modified Hook-Brown critierion.②On the basis of the on-site field, the 2D numerical model is established by using numerical software ANSYS9.0, and the optimization of the stope structure is made by means of multi-scheme coMParison. It is shown from numerical results that: the reasonable range of room size is 22～25m or 25～30m, meanwhile, the front is named for recommended scheme 1, the back is named for recommended scheme 2.③The 3D numerical model is applied into study the two rational schemes and the further optimization of the size of sill pillar and the rib pillar is investigated. More over, the most reasonable mining structure sizes areobtained.④The stability of the preliminary scheme and the both recommended ones is analysed by using 3D numerical simulation method. It is revealed from the numerical results that: In the preliminary scheme, the stability of the sill pillar is poor due to the high stress concentration and the obvious plastic deform, while that of the rib pillar is fine, And those results are in good agreement with the engineering practice. It is also observed from the numerical results that: the sill pillar is more stable in the recommended schemes than the preliminary one.After adjusting the location of pointed pillars, the stress concentration and plastic deformation are decreased, and the stability of point pillars is improved greatly, meanwhile, parts of the sill pillar should be supported yet in order to improve the stability of stopes.⑤On the basis of the above optium stope structure parameters, optimization of the mining sequence is investigated by using 2D numerical simulation method. It is indicated from the numerical results that : The"free-of-pressure arch"effect will form when the working face configuration type of continuous mining is similar to"品", which will improve the stope stability.