Study On Efficient Stratified Mining System Of Medium-thick And Gently Inclined Phosphorite In Maluping

One of the key technologies for high efficiency stratified mining of medium-thick and gently inclined phosphate ore is the stope mining system.At present,the system has not been well solved in the large-scale mining of medium-thick and gently inclined phosphate ore.In this paper,the medium-thick moderately inclined orebody in the 640 m middle section of Maluping Mine is taken as the research object.The method of on-site investigation,indoor experiment,theoretical analysis,and numerical simulation is combined to study efficient stratified mining system scheme in stope.The main work and research results are:(1)Mine engineering geology survey and testing: existing physics and mechanics test data of ore rock,and uniaxial compressive strength supplementary test,can obtain more accurate ore rock mechanical parameters;on-site joint crack investigation,joint average spacing is 37.3cm and the joint density is 2.68 pieces/m.(2)Optimization of stope structure parameters:According to the simply supported beam theory,empirical formula and mine production capacity requirements,the length of the mine room is initially determined to be 50 m,the height of the mine room is 10 m,the width of the mine room is 14~18m,and the width of the pillar is 12~ 16 m.Using the MIDAS/GTS software,numerical simulation tests were conducted on the widths of nine different types of mine houses and pillars,and comprehensive comparisons yielded the optimal stope structure parameters,that is,the length of the mine room is 50 m,the height of the mine room is 10 m,the width of the mine room is 16 m,and the width of the pillar is 14 m.(3)The bottom structure of the stope is preferred: According to the mining characteristics of Maluping Mine and the applicable conditions of the three types of bottom structures,the bottom structure of the sulcus-ditch type mine and the electric-tank ore is determined,and the bottom structure of the stumbling-groove combined with electric tunneling is given.(4)Bottom structure stability analysis: The stability of the bottom structure was analyzed from the static load excavation and blasting dynamic load respectively using MIDAS/GTS software.Under the static load and dynamic load,the whole bottom structure can maintain stability.Local support and reinforcement are required.Dynamic analysis determines that the thickness of the isolation pillar is 4m.(5)Stratified ore control research: Using a blasting,layered ore mining process,detailed introduction of the process of layered ore mining,giving a high-efficiency stratification program.