| Nowadays, non-pillar sublevel caving is a high efficiency mining method the widely adopted of underground working iron mine, of which three structural parameters, that is height of subsection, drift spacing and ore breaking. Generally speaking, the height of subsection and drift spacing have already been selected during the preliminary design. Once determined, it is difficult to optimize and adjust in the process of production, while ore breaking is flexible. So in practice, the optimization of ore breaking is directly related to the promoting the target of safety, efficient and cost recovery goals in the mine. Now structural parameters is planned further increasing by Meishan iron mine, the height of subsection will be increased to18m, the drift spacing is expanded to20m, all of these is to develop the product test under the18×20m structural parameters. This paper combines the Meishan construction projects with the ore body conditions of Meishan iron mine, and develops the optimization study of ore breaking under different endwall dip angle of Meishan iron mine.Firstly, this paper makes theoretical analysis, determines the optimal ore breaking and finds the mathematical model of ore breaking and drawing index which is based on the stochastic medium theory and the law of’The shape of caving ore body is consistent with configuration of loose.Secondly, according to some law of increasing,principles of widely simulation and the SLS is made use of to carry on an imitating experiment on8drawing pace of24kinds of schemes under three endwall dip angle90°,85°and80°.Moreover, this paper gets that the optimal drawing pace is4.4m, the optimal endwall dip angle is90°.Through the face-end ore-drawing experiment, this paper gets the curves of the eccentricity of draw body, return equation and morphological features of draw body, and combined with Theoretical analysis, gets that the optimal ore breaking is4.31～5.38m.On the basis of theoretical analysis, computer simulation research and the face-end ore-drawing experiment, the reduced-scale physical models experiment is carried on with9kinds of schemes of endwall dip angle is80°～90°, under18X20m structural parameters. By the statistical analysis of this experiment,this paper finally decides that the optimal drawing pace of Meishan iron mine is4.4m, endwall dip angle is90°Lastly, this paper does research on the blasting parameters of Meishan iron mine which combined with the finding of ore breaking under different endwall dip angle, gets the key data as follows, diameter of blasting holes is89mm, hole space is3.2m, Edge horn hole is60°, Explosives unit consumption is0.3kg/t and the automatic program of stoping blast parameters has been developed.Based on above work, theoretical bases is available for industrial test of Meishan iron mine under the structural parameters of18*20m.At the same time,,the correctness of research conclusions is validated by combining with the result of industrial test of Meishan iron mine. Practice shows the research method in this paper provides effective means and measures for the optimization design of ore breaking under the different endwall dip angle. |
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