Optimization Of Stope Structure Parameters Of V_5-2 Ore Body In Chang'an Gold Min

Changan Mine Section of Jinping Changan Mining Co.,Ltd.（referred to as Changan Gold Mine）is located in Tongchang Village,Tongchang Township,Jinping County.The main orebody V_5-2 occurs in the altered rock zone in the east of F₆ fault fracture zone,which is thin,medium-thick,thick-inclined and steeply inclined,the joints and fractures are well developed,the stability of ore and rock is general～poor,and the geological conditions are complex.The original shallow hole retention method and non-pillar sublevel caving method are difficult to adapt to the geological and mining technical conditions of V_5-2 deposit,and the existing tailings reservoir capacity is insufficient,tailings must be backfilled into the underground goaf,so there is an urgent need to study new mining methods.Taking the V_5-2 orebody of Chang’an Gold Mine as the research object,through on-site investigation,sampling and indoor rock mechanics test,combined with the present situation of mine production,using the methods of theoretical analysis and numerical simulation software analysis,the stope stability of the stope with stope method above 1450m is analyzed,and the method of natural caving to deal with goaf is put forward.Aiming at the orebody below 1450m,the stope structure parameters of the upward approach filling method proposed by the research group are optimized,and the following research results are obtained:（1）the surrounding rock mass of roadway at 1450m～1500m elevation is investigated and sampled,and the physical and mechanical parameters of rock are obtained by rock mechanics test;according to the quality classification of rock mass,the sandstone and orebody near the upper wall of V_5-2 orebody is grade IV rock mass,and the lower wall breccia is grade V rock mass;the mechanical parameters of rock mass are calculated to provide mechanical parameters for the follow-up numerical simulation method.（2）according to the geological conditions of the deposit and the technical and economic conditions of mining,it is proposed that the sublevel open-stope method is adopted to mine the V_5-2 orebody above 1450m and the upward filling mining method is used to mine the V_5-2 orebody below 1450m.（3）the critical caving area of the upper wall of the stope is calculated by Mathew chart method,and the three-dimensional model of the ore section is established by using the numerical software MIDAS-GTX-NX,and the stope structure parameters are simulated and analyzed by using FLAC^3D numerical simulation software,the changing rules of stress,displacement and plastic zone in the process of mining are obtained,and the method of natural caving to deal with goaf is put forward.（4）the stope structure parameters of the section below 1450m are optimized by using the numerical simulation software FLAC^3D,and the changing states and rules of stress,displacement and plastic zone with different section sizes are analyzed.It is proposed that the reasonable section size of V_5-2 orebody is(3-3.5m×（3.5m）m.On the basis of on-site engineering geological investigation and rock mechanics test,this paper studies the ground pressure activity law and rock mass caving law of V_5-2 orebody above 1450m,and puts forward the method of natural caving to deal with goaf;according to the mine geological conditions and mining technical and economic conditions,the upward approach filling mining method and stope structure parameters are studied and put forward,which solves the problems of insufficient tailings reservoir capacity and large ore loss and dilution.