Southern-African Dilokong Chromite Mine Mining Methods Selection And Optimization Of Stope Structure Parameters

Southern-African Dilokong chromite ore body’s dip mean is 10°, average thickness is 2m. The thickness of LG6 seam is about 1.0～1.2m and be covered with thickness of about 0.5 ～0.6 m pyroxenite, and there is thickness of about 0.5 m of LG6a chromium seam upper pyroxenite, present the typical characteristics of gently dipping thin orebody. Due to unreasonable mining methods, LG6a is not mined in the course of exploitation process, thereby causing to the a large number of mineral resources loss; As a result of stope structure parameters is not reasonable, the ground pressure activities is frequent and appeared severe deformation failure. Therefore, based on the reasonable stope structure parameters of mining design for next phase mining is very important. Based on the engineering geological investigation and rock mechanical test, apply the way of combining theoretical analysis and numerical simulation to select mining method and optimize stope structure parameter.(1) This paper carried out geotechnical investigation, mastered metallogenic condition and rock mass quality classification, and obtained rock mechanical test through rock mechanical test.(2) Based on influencing factors of selection mining method as evaluation index, and apply fuzzy comprehensive evaluation to confirm the best mining method of Dilokong mine for down steps and cross pitch of overall room-and-pillar mining.(3) Combined with the characteristics of the simulation problems, analyzed aspects related to modeling, including determination of structure parameter, imitation of model reasonable scope and boundary condition, etc., and on this basis, established numerical model and calculation scheme.(4) Expound instability form and mechanism, and put forward the destruction criterion of rock mass through the analysis of commonly used Measured Data, Rock Strength Theory, Permissible Displacement Criterion and Plastic Zone Criterion.(5) Combined instability mechanism of stope and unstable failure of criterion, obtained that the best stope structure parameter of each FLAC3D scheme is that the length of the room is 50 m, the span of room is 26 m, the size of column is 5 m×5 m, the space of column is 2 m when stope exposure area was 1300 m2. And design the suitable mining scheme for gently dipping thin orebody of Dilokong mine.