| Non-pillar sublevel caving method has the advantages of safety,high efficiency and easy to realize large-scale production equipment,so it is widely used at home and abroad.Big structural parameters are the main development direction of this mining method.Relevant experts and scholars have carried out a large number of deeper researches in multiplicity on this area,and have also obtained many useful research results.However,there are few reports on the influences on which the boundary conditions formed under different side angles effected on broken ore and waste flowing and ore drawing effects.Based on the physical drawing experiments with single drawpoint-sublevel and multi-drawpoint-section under 6 kinds of side hole angles,the characteristics of mixed rock,ore drawing index,shape of drawing-out body,residual ore body under different side hole angles are studied comparatively.The following research results have been achieved:(1)The sizes of the side hole angles has a certain influence on the shape of the drawn-out body and the residual ore-body.The side hole angle increases,and the fluidity of ore rock on both sides of the drawpoint becomes better,the residual area of the ridge of the ore becomes smaller,The relation between the shape of the discharge body and the position of the ore rock changes with the change of the side angle,and the relationship between the shape of the drawn out body and the position of the ore body changes with the change of the angle of the side hole.Furthermore,the ore drawing effect is affected.(2)The size of the side hole angle has a certain influence on the characteristics of the mixed rock during drawing process.Under the condition of ore drawing via the single drawpoint and the first mining stage in multi-sublevel mining,the accumulative mixing ratio decreases with the increase of the side hole angle when the ore drawing quantity is at the same.Under the condition of next sublevel mining,with the increase of the side hole angle,the accumulative rock mixing rate shows the characteristics of "low,high and low" when drawing later.(3)The sizes of side hole angles has a certain influence on the ore loss rate and the dilution rate.it shows that with the change of the side hole angle from small to large,the loss rate and the dilution rate changes from low to high,and then from high to low.(4)The size of the side hole angle has a great influence on the ore drawing effect.Under the condition of single drawpoint and the first mining stage in multi-sublevelmining,the bigger the side hole angle is,the better the ore-drawing effect is;but under the multi-sublevel ore drawing condition,with the change of side hole angle from small to large,the ore drawing effect changes from high to low,and then from low to high.With the decrease of mining sublevels,the side hole angle of the best ore drawing of the first,the second and third sublevel is at 35°,55° and 5°,and the side hole angle of optimum effect in integral ore drawing is 55°.(5)The width of the drawpoint also has a great influence on the ore drawing effect under different side hole angles.The larger the width of drawpoint is,the better the ore drawing effect is,it shows that the ore drawing effect is better with the increase of the drawpoint width and the decrease of the side hole angle.The experimental results show that when the width of the drawpoint is at 110 mm,100mm and 90 mm,the best ore drawing effect is at the side hole angle of 35°,45°and55°. |
PDF Full Text Request