无底柱分段崩落法损失贫化细部控制方法研究

无底柱分段崩落法以其安全、有效、适应性强等优点被国内外金属矿山广泛使用;但矿石损失贫化大的问题多年一直未得到解决。针对这一问题，研究了回采过程中矿石损失贫化的发生过程与细部控制方法，分析了分段之间进路非菱形布置、出矿口眉线破坏、爆破隔墙、大块堵塞出矿口一侧等常见现象对放出体形态的影响，探讨由此引起的对崩落矿岩散体几何形态吻合度的降低程度，发现正是这些常见现象制约了崩落矿石的移动范围与总体放出速度，加大了崩落矿石的残留量与放出矿石的混岩量，导致矿石损失贫化居高不下。据此提出了加密回收进路、改进采场结构、控制炮孔不装药长度保护眉线、及时处理堵口大块和保障整条进路菱形布置的细部控制方法。该方法用于邯郸市北洺河铁矿与灯塔市小汪沟铁矿，取得显著成效。

Approach of Ore Loss and Dilution Control in Sublevel Caving Method

The sublevel caving method is widely used in metal mines at home and abroad for its safety,efficiency and strong adaptability. However,this method has problems of high ore loss and dilution, which have not been well resolved for many years. To solve this problem,the ore loss and dilution in the process of mining recovery and the approach of ore loss and dilution control should be studied. The effects of non-rhombus layout of drifts,the destruction of the eyebrow line,the blasting partition,the ore-drawing holes blocked by large ores on the pattern of the extraction ellipsoid and its resulting in reduction of coincidence degree of the geometric forms of the caved ores granular were analyzed. And it is founded that it was these common phenomena that restricted the moving range and the overall drawing speed of caved ore,increased the remnant amount of the caved ores and the amount of mixed rock of extracted ores,and gave rise to high ore loss and dilution. Therefore,the detail con-trol method,with the aim of adding one more recovery drifts,controlling blasting holes length without charging,timely dispose large ores and staggering production drifts,was proposed. This method was adopted in Beiminghe Iron Mine ( in Handan) and Xiaowanggou Iron Mine ( in Dengta) ,with remarkable experimental effect.