Influence Of Draw Hole Size On Ore Drawing Effect

Sectional caving method is the first mining method that tends to mechanization and high-strength mining ore in China.Because the method is carried out under the overburden bed,large loss and dilution of ore and poor recovery effect are very outstanding.Therefore,domestic and foreign experts and scholars have done a lot of research on the ore drawing theory,structural parameters,the formation of overburden and the technology of ore-drawing,and have achieved fruitful results.Based on the size of ore drawing hole,the effect of ore drawing hole size on ore drawing effect is further studied in this paper.When the ore is lowered under the condition of rectangular ore-drawing,the size of height and width will directly affect the flow of ore-bearing rock,and then affect the ore-drawing effect.In this paper,the following works are done:(1)On the basis of the pillar less sub level,three single-stage physical model experiments of different width and different height of ore-drawing hole are designed,The influence of the height and width of ore drawing hole on the mixing ratio of waste rock,the recovery rate of ore and the shape of the ore drawing body are analyzed regularly.(2)On the basis of single-pass single-segment physical model experiments,three groups of multi-segment physical model experiments are designed which are closer to actual production,By changing the height and width of the ore-drawing hole,the influence on the ore-drawing effect of each approach and each section is analyzed.(3)It is shown that the width of the ore-drawing hole will gradually exp and from 4m to 5.5m or the height of the ore-drawing hole will gradually rea se from 4.5m to 3.5m and it can improve the recovery of ore,which can be used f or practical production guidance.(4)It is found that the width of the ore-drawing hole is between 4m and5 m and the ratio of height to width is between 0.70 and 1.00,The effect of changing its size on the waste rock mixing is less,and the effect of changing its width on ore recovery is less in the 4.5m-5m fan-envelope of the ore drawing hole.(5)The width of the ore-drawing hole gradually expands from 4m to 5.5m,the shape of the discharge body will become "wide" in the direction of the vertical entry and "narrow" slightly in the direction of the approach road.The height of the ore-drawing hole gradually decreased from 4.5m to 3.5m,the shape of the discharge body becomes "wide" in the direction of the vertical entry.