| The mining of extremely fractured thick metal ore bodies has been a technical problem that plagues the safe and efficient mining.In this paper,based on this NSF project(No.51764013),a metal mine in Henan Province with extremely fractured thick and difficult to mine bodies as the engineering background,based on the geological data of the mine,combined with the indoor rock mechanics test parameters and field research,relevant research and exploration are conducted in order to solve the mining technical problems of the mine.The rock mechanical parameters are reduced by the Hoke-Brown strength criterion to obtain the rock mechanical parameters;the FLAC3 D software is used to perform numerical simulation analysis on the simulation plan to determine the stability plan;the analytic hierarchy process(AHP)and fuzzy mathematics method are used to construct the optimal model Determine the optimal mining method;again use FLAC3 D numerical simulation to compare and analyze the designed stope structure parameter schemes,and finally determine the optimal stope structure parameters.Some main research results are obtained through the above experimental analysis:(1)Through the laboratory rock mechanics test,the uniaxial compressive strength,elastic modulus,tensile strength,Poisson’s ratio,cohesion of three rock samples of plagioclase,mixed granite and ore rock in natural state were obtained,internal friction angle,rock quality index RQD value and rock integrity coefficient Kv value.the rock mechanics parameters are reduced to rock mass mechanics parameters by using methods such as the Hoke-Brown strength criterion.The GSI value is determined by calculating the structural plane condition factor and the volume joint number of the rock mass.Finally,it is determined that the GSI value of molybdenum ore is 20,the GSI value of amphibolite is 53,and the GSI value of mixed granite is 32.By calculation,the rock mass mechanical parameters suitable for simulation are obtained,provide a basis for follow-up research.(2)According to the geological engineering conditions of the mine,the characteristics and occurrence of the ore rock,and the mining experience of similar mines,the pillarless sublevel caving method,natural caving method,upward layered approach filling method and There are four mining methods with downward layered approach and filling method.Then use the rhino modeling software(Rhino7)to establish a reasonable theoretical model according to the occurrence of the ore,and then divide the grid through the griddle plug-in,use FLAC3 D numerical simulation to analyze the stability of the stope of the four mining methods,and select Appropriate plan,it is preliminarily concluded that there are problems with the stability of the caving method,and it is not suitable for use.Reuse Analytic Hierarchy Process(AHP)and fuzzy mathematics method to construct a theoretical model for the influencing factors of the previous methods,and determine the maximum membership degree.Among them,the membership degree of the four methods is0.4773 for sublevel caving without sill and natural The caving method is 0.5614,the upward layered approach filling method is 0.4081,and the downward layered approach filling method is0.7198,so the downward layered approach filling method is selected as the optimal mining method for this difficult ore body.(3)According to the selected optimal mining method,consult the relevant literature on the empirical structure parameters of the method,design a variety of stope structure parameter schemes with a width range of 2～5m and a height range of 2～5m,using FLAC3 D simulation The software simulates the above scheme.Finally,according to the simulation results,a simulation program with a width of 2m and a height of 2m is determined as the optimal stope structure parameter.According to the selected structure parameters,the project’s mining quasi-cutting engineering volume and the ore volume in the ore block are preliminarily designed.According to the proportion,the number of stopes at the same time is 4,so the annual production capacity of the stope is 155520t/a.Based on this production capacity,the volume of filling slurry required per hour is 16.96m~3/h.The bottom layer of the artificial false roof adopts a tailings cemented backfill with a lime-sand ratio of 1:6 and a solubility of 72%,and a backfill with a lime-sand ratio of 1:10 and a solubility of 65% for the upper part.The research results of this paper provide a scientific and useful reference for the safe and efficient mining design of the extremely broken and refractory ore bodies in this mine. |
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