Influence Of Drawpoint Sizes On Inserts Drawing Technique

The problem of high ore loss and dilution in the mining of inclined medium-thick ore body by sublevel caving method is mainly caused by direct contact between the blasting ore and the caving waste rock.In order to solve this problem,this article takes the mining of inclined medium-thick ore body as the research object,and based on the inserts drawing technology,the comparative experiment of inserts drawing and conventional drawing is carried out,and the analysis is carried out.The impact of the height of drawingpoint and the width of drawingpoint on the inserts drawing technology is studied by a combination of physical similarity simulation experiments,theoretical analysis and numerical simulation.The main research contents of this paper are as follows:(1)Based on the effect of the inserts in the silo and the flow law of the mediumthickness inclined ore body,this paper proposes the inserts drawing technology.The basic principle of this technology is to insert steel pipes at the contact point of drift to form a diversion isolation plate(inserts).By changing the diversion isolation plate different sequence,the effective isolation of the ore and rock can be realized.(2)A comparative experiment of conventional drawing and inserts drawing was carried out.Drawingpoint width was 3-6m,and the height was 3m.The experimental results show that the ore recovery rate increases by an average of 26.45% under the same dilution rate as compared with the conventional end drawing,which verifies the inserts drawing technology to effectively reduce the loss of ore.(3)Based on the inserts drawing technology,physical simulation tests of 4different drawingpoint widths and 3 different drawingpoint heights,which analyzed the influence of different drawingpoint sizes on the ore loss and dilution of inserts drawing technology.The results show that: appropriately increasing drawingpoint width or lowering the height can effectively reduce the loss of ore;increasing drawingpoint width has no obvious effect on the dilution rate,and reducing the drawingpoint height can effectively reduce the dilution rate.(4)Based on the inserts drawing technology,using the three-dimensional particle flow numerical simulation software PFC3 D,12 sets of drawing models with different drawingpoint sizes were established respectively.The results show that the effect of different drawingpoint sizes obtained by the numerical simulation experiment on the drawing effect of the inserts drawing technology is basically consistent with the results of the physical experiment,which further verifies and perfects the physical experiment results of the inserts drawing technology.