无底柱分段崩落法放矿规律的数值试验研究

Research on Numerical Simulation of Ore Drawing Rules in Pillarless Sublevel Caving

为了解决无底柱分段崩落法的损失贫化较大的问题,数值模拟了崩落体的形态以及放矿过程中崩落体和放出体的形态演变过程。结果表明,崩落体形态接近于椭球缺,呈上宽下窄状,崩落体的宽度约为崩矿步距的1.2～1.5倍,但崩矿步距对崩落体的高度基本没有影响;放出体的形态也是近似椭球缺形,其演变规律表现为由初态的上宽下窄逐渐演变为上尖下宽,说明随放矿进行崩落体内矿石垂直流动性逐渐加强。研究中对不同步距下的放矿技术指标进行了统计分析,结果表明,放矿过程中,出矿口矿石品位是震荡式降低的,造成品位震荡降低的原因是少量正面废石的混入,而造成放矿截止的主要原因是顶部废石的大量混入。

To solve the problem of high loss and dilution of ore in the pillarless sublevel caving,the shape and evolution of caving body and drawing body in end ore drawing are systematicaly analyzed and researched. The results showed as follows: firstly,the shape of caving body is approximate to a ellipsoid with wide top and narrow bottom; the width of caving body is about 1. 2 ～ 1. 5 times caving spacing,but there is little relationship between the height of caving body and caving spacing. Secondly,the shape of draw body is also approximate to a ellipsoid and the evolution process presents from the shape of wide top and narrow bottom in the beginning to that of a spike-like top and wide bottom gradually which proves that the vertical mobility of ore particles is gradually strengthened as drawing goes.Thirdly,statistical analysis of drawing technology index in different caving spacing shows that the ore grade of the drawing hole is oscillatory decreased during ore drawing and the reason for this phenomenon is the mixing of a small amount of front waste rock. It is the mixture of large amounts of top waste rock that causes the cutoff grade of ore drawing.