| Pillarless sublevel caving method is introduced into our country since the 1960s,with its good security,high extraction efficiency,low cost advantages,has been generally applied in underground metal mines in China.But the mining method has a extremely serious question,is also one of the problem in the mining industry experts and scholars,that is that the ore dilution is very serious.The main cause of causing dilution ore is directly contact ore-rock in the process of releasing ore,with mixing area surface widely and with more opportunities.If waste rock is unreasonably control,mining enterprises the level of product quality will decline,the secondary product processing cost.The choice of stope structure parameters combination is reasonable or not is one of the factors influencing the ore recovery index,reasonable stope structure parameters can bring obvious economic benefit to mine,on the contrary,unreasonable structure parameters combination will increase production of ore dilution rate,reduce recovery index etc.Therefore,in order to improve the overall economic benefit of mine enterprise,it is necessary to study on optimization of stope structure parameters.The research topic of this thesis is to solve the serious ore loss and dilution rate in Dahongshan iron mine,ore recovery rate is relatively low.Dahongshan iron mine after using the large structure parameters 20 x 20,the problem ore dilution and loss is particularly prominent.To solve this problem,mainly complete the following work:1、Ore experiment in the lab for monomer,USES the single ore mine mouth,by marking particles released the order and mapped the release of hole quantity body form,and through the regression fitting the blownoff-ore rock ore medium flow parameters:α=1.814;α1 = 0.179;β= 1.535;β1= 0.313;k= 0.192,using the method of empirical formula method and the medium flow effectively with preliminary determine Da hongshan iron ore into the road distance of 23.8 m and caved ore interval is 5.23-5.54 m.2.Design of orthogonal test table to arrange 9 groups of different structure parameters combination ore scheme,and uses the points between the three-dimensional model of ore ore indoor experiment,experiment study of samples taken from mines,respectively in the process of pass for low dilution and current cut-off grade ore,determine the mining ore cut-off grade is 18%,and it is concluded that when the sublevel height of 30 m,route distance is 25 m and 20 m ore caving step distance of 5.5 m,ore recovery index to achieve better.3、Through the computer simulation,PFC,respectively,set up different structure parameters combination model of ore drawing process,with low dilution and two cut-off grade ore drawing mode strictly control the ore,when the ratio of the release of ore and waste rock quality reach a set cut-off condition,stop the ore,ball number and save the record release ore-bearing respectively,then the result of the released data and statistical analysis,draw for mine sublevel height of 30 m,approach the spacing of 25 m and interval is 6.5一 7 m ore.Comprehensive analysis on Dahongshan iron mine about the low dilution ore laboratory test,the results of numerical simulation to determine the mining low dilution drawing,put forward the appropriate a great iron ore stope structure parameters for:30 m sublevel height,route distance 25 m ore caving interval 5.2 to 5.4 m,into the road tunnel size 6.1 × 4.1 m(width × height). |
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