低贫化放矿矿石覆盖层合理厚度研究

预留矿石作为覆盖层是实现低贫化放矿的途径之一,为了使其降低矿石损失贫化的作用得以充分发挥,有必要对其预留厚度进行进一步研究。基于低贫化放矿原理,以纯矿石放出体尽可能大、放矿过程中矿石覆盖层厚度维持不变为原则,总结出合理厚度的计算方法,即在随机介质放矿理论的基础上考虑单次出矿量,首先确定出合理的放出体高度,再由此确定矿石覆盖层的厚度。以程潮铁矿西区矿柱回收采场为算例,计算得放出体高度为28m,矿石覆盖层厚度为40m,并设置室内放矿实验验证其可靠性。实验结果表明,矿石覆盖层厚度达到40m时,矿石回收率和废石混入率都取得较优水平,矿岩界面起伏程度相对较小,说明此理论计算方法是可靠的。

Study on Reasonable Thickness of Ore Covering Layer in Low Dilution Ore Drawing

Reserved ore as overburden is one of the ways to realize low dilution ore drawing. In order to make full use of its role in reducing ore loss and dilution,it is necessary to further study the reserved thickness. Based on the principle of low dilution ore drawing,the calculation method for reasonable thickness is summarized according to the principle that the ore body is as large as possible and the thickness of ore overburden remains unchanged during ore drawing. The reasonable height of ore body is determined,and then the thickness of ore overburden is determined based on the random medium ore drawing theory. Taking the pillar recovery stope in the west area of Chengchao Iron Mine as an example,the height of the ore body is calculated to be 28 m,and the thickness of the ore overburden be 40 m. The reliability of the method is verified by indoor drawing experiments. The experimental results show that when the thickness of ore overburden reaches 40 m,both the recov ery rate of ore and the mixing rate of waste rock are better,with less fluctuating degree of ore-rock interface,which shows that the theoretical calculation method is reliable.