Numerical simulation of the reasonable size of the pillar with Wongawilli mining method
WANG Meng;QI Te;QIN Hongyan;QIU Zhanwei;Mining College, Liaoning Technical University;Post-Doctor Station, Shanxi Coking Coal Group Co.LTD.;College of Safety Engineering, North China Institute of Science and Technology;
Background, aim, and scope Bauxite is a water-based alumina, the composition of the variable natural multi-mineral mixture, is the most important ore to extract aluminum. Wachangping bauxite for the first time in the industry to adopt long-walled fully mechanized mining technology, resulting in some corner of the mine is difficult to arrange the regular mining face for mining. Therefore, the FLAC3D numerical simulation software is used to recover the marginal ore body of the mine by using the Wongawilli mining method. And the purpose is to provide the basis for the mining work of the mine. Materials and methods In this paper, based on the theory of simply supported beam, fixed beam and double-zone constraint theory, combined with numerical simulation method, the size of the inter-pillar pillars with different widths is calculated when the Wachangping bauxite is recovered by Wongawilli mining method perform a simulation analysis. Results The results show that the vertical stress and plastic zone change with the increase of the number of mining caves. When the interlayer pillar is 0.5 m, the whole plastic shear failure occurs in the mining process of the sixth mining cave, and the pillar is completely broken and can not play the role of protecting the current mining cave and temporary support roof role. When the size of the pillar is 1.0 m, the local pressure is still lower than that of the original rock, and the plastic shear and tensile destruction, and even through the entire pillar, the basic loss of support capacity. And then the two pairs of knife between the pillars of plastic shear damage, but still has a certain ability to support, played a role in protecting the current mining cave and temporary support roof; and set aside 1.5 m knife between the pillars, from the mining of the fifth as the number of mining caves increases, the vertical stress of the pillars continues to be maintained at higher stress. After the mining, the pillars are always in the elastic steady state, and the supporting capacity is kept. The roof can not collapse in time, easy to cause a large area of roof, leaving security risks. Discussion According to the three schemes proposed in this paper, it is a reliable technical means to determine the reasonable size of the castle of the Wongawilli mining method by numerical simulation method, which has a certain guiding effect on the exploitation of the marginal ore body. Conclusions According to the structure of the simply supported beam and the fixed beam structure, the width of the mine is 5 m.According to the formula of the small pillar protection pillar, the width of the fault is 19 m. According to the double-zone constraint theory, the theoretical width is 0.91 m. Based on the actual conditions of the Wachangping bauxite, the numerical simulation method is used to analyze the three schemes of 0.5 m, 1.0 m and 1.5 m. The calculation results show that the scheme of 1.0 m is the most reasonable, to ensure that the knife pillars to play a temporary role in supporting the roof, and will not cause a large area of the roof so as to leave a security risk. Recommendations and perspectives As the longwall mining residual pillars and irregular blocks and other ore bodies are increasing, the corner ore body recycling problem has become a urgent problem to be solved. This paper has some reference significance for improving the recovery rate of mine resources and optimizing the reasonable width of the pillars.