Faculty of Engineering, Mine Engineering Department, Tarbiat Modares University, Tehran, Iran.
Environ Monit Assess. 2020 Aug 28;192(9):605. doi: 10.1007/s10661-020-08550-5.
Block sequencing is of great importance in an open-pit mining operation. Sequencing is usually performed to maximize the net present value (NPV). Also, from the environmental viewpoint, the sequence of dumping mined materials is of significant value in the sulfide mines. The potential acid-forming (PAF) waste rocks in these mines can seriously damage the environment due to the formation of acid mine drainage (AMD). To prevent the exposition of the PAF materials, it is essential to design suitable block sequencing. For this purpose, encapsulation of the PAF rocks by non-acid forming (NAF) rocks should be considered during waste dumping. However, this method can impose unnecessary re-handling costs. This issue is due to the determination of the waste-dump sequence based on improper block sequencing obtained from the previous models with the NPV maximization strategy. In the present study, a mixed-integer programming (MIP) model is proposed for generating proper block sequencing taking into account the composition of waste rocks. The main objective of the proposed MIP model is to maximize NPV and minimize the destructive environmental effects of PAF materials dumping. The CPLEX solver was applied to solve the proposed model in small datasets. Then, an artificial bee colony (ABC) is implemented to find out optimum block sequencing and waste dumping (BSWD) on a large scale. The proposed approach was examined employing several sets of data. The obtained results were compared with those of the CPLEX solver as a benchmark. An approximate gap of 2% demonstrates the efficiency of the proposed approach.
露天矿开采作业中，区块排序非常重要。排序通常是为了最大化净现值（NPV）。此外，从环境角度来看，硫化物矿中开采材料的倾倒顺序具有重要价值。这些矿山中的潜在酸性形成（PAF）废石由于形成酸性矿山排水（AMD），可能会严重破坏环境。为了防止 PAF 材料暴露，设计合适的区块排序至关重要。为此，在倾倒废物时，应考虑将 PAF 岩石用非酸性形成（NAF）岩石进行封装。然而，这种方法可能会带来不必要的重新处理成本。这是由于基于先前采用 NPV 最大化策略的模型获得的不当区块排序来确定废物倾倒顺序。在本研究中，提出了一种混合整数规划（MIP）模型，用于生成考虑废石组成的适当区块排序。所提出的 MIP 模型的主要目标是最大化 NPV 并最小化 PAF 材料倾倒对环境的破坏性影响。CPLEX 求解器应用于解决小规模数据集的提出模型。然后，实施人工蜂群（ABC）来大规模寻找最佳区块排序和废物倾倒（BSWD）。该方法通过多组数据进行了检验。将获得的结果与 CPLEX 求解器的结果进行了比较，作为基准。大约 2%的差距证明了所提出方法的效率。
