急倾斜薄矿脉中深孔落矿爆破参数优化

依托金厂沟梁金矿中深孔落矿工业实验，开展急倾斜薄矿脉中深孔落矿爆破参数优化研究。基于非线性动力分析有限元软件ANSYS/LS-DYNA开展多种方案的数值模拟，分析了不同爆破参数下窄矿脉爆破应力场分布特征和窄矿脉爆破夹制作用下爆破裂隙区域的形成过程。计算结果表明，抵抗线在0.8~1.2 m范围内，相同孔距下自由面中心位置有效应力峰值随着抵抗线增大呈现衰减趋势；孔距在0.9~1.6 m范围内，相同抵抗线应力峰值随孔距增大而增大，孔距增大的同时，上下盘围岩损失程度也随之增大。选择孔网面积作为衡量依据，随炮孔密集系数增大，有效应力增量减缓，密集系数超过1.5后，矿石损失贫化加剧。综合各方案模拟结果，1.0 m×1.4 m为最优的爆破参数。将优化结果用于现场实验，爆破后采用三维激光扫描系统进行评估，实测爆区体积为设计体积的91.8%，爆破并未导致矿体上下盘围岩垮落，爆破效果良好。

Blasting parameter optimization of medium-depth hole caving for steeply inclined thin veins

On the basis of the industrial experiment of medium-depth hole caving in Jinchanggouliang Gold Mine, the authers carried out the optimization research of hole pattern blasting parameters. ANSYS/LS-DYNA was used to make several schemes of numerical simulation. Then the distribution features of the blasting stress fields under different hole pattern parameters and the formation process of the fractured blasting regions under the constrained blasting effect of narrow vein were obtained. The results show that when the resistance line is between 0.8 and 1.2 m, under the same hole spacing, the effective stress peak of the central free surface decreases with the increasing resistance line; when the hole spacing is between 0.9 and 1.6 m, it increases with the rising hole spacing under the same resistance line. As the bore hole density coefficient increases, the stress increments slow down, and the ore loss and dilution aggravate, if the bore hole density coefficient is more than 1.5. Comparison of all the schemes displays that the 1.0 m×1.4 m hole pattern parameter is the best. After employing the optimization results for the field experiment and with the CMS evaluating the blasting effect, the actual blasting zone volume covers 91.8% of the designed volume. The blast, with sound effect, did not cause the top and bottom side wall orebody to cave.