A landfill based approach to surface mine design

Abstract

Surface mining operations extract a large quantity of waste material, which is generally disposed into a dump area. This waste can cause a series of environmental problems ranging from landscape deterioration to acidic water generation and water pollution. Therefore, mine waste management is a significant task in mining operations. As known, in strip mining, the overburden is not transported to waste dumps but disposed directly into adjacent strip which was mined out. This concept can be adapted for mine planning of relatively horizontal deposits through a mixed integer programming (MIP) model. The main idea behind this work is that, in one pit, production voids created in early year of mining are used for waste landfilling in late years of production. In other words, in addition to external dumping, a landfilling option within the same pit is proposed for mine design optimization. The problem is formulated as maximization of the net present value (NPV) of the mining project under the constraints of access, landfill waste handling, mining and processing capacities. A case study using a data set was carried out to see the performance of the proposed approach. The findings showed that this approach could be used in waste management incorporating a landfilling option into mine planning. As a result, material handling costs decrease, and environmental compliance increases due to less external waste quantity.

摘要

露天采矿作业会剥离出大量的废弃物, 通常排置于排土场中。 这些废弃物会造成一系列的环境问题, 从景观恶化到酸性水的生成以及水污染等。 因此, 矿山废弃物管理是采矿作业的一项重要任务。 在露天采矿中, 上覆岩土层并非运输至排土场, 而是直接排置于已开采完毕的相邻采坑中。 利用混合整数规划 (MIP) 模型, 可将此想法应用到较平缓矿床的矿山设计规划。 本项工作的主要思路为: 在一个采坑中, 初期因采矿产生的采空区可被用于后期生产所需的废弃物填埋。 除了将废弃物排置于外部的排土场, 本文提出了一种同采坑中的填埋可选方案用于矿山设计优化。 该方案的提出, 是为了在运输条件、 废弃物填埋处理、 以及采矿和选矿能力的限制下, 实现采矿工程净现值 (NPV) 的最大化。 为了验证所提出方法的效果, 利用采集的数据开展一个案例分析。 研究结果表明, 此方法可用于将废弃物填埋可选方案纳入矿山规划的废弃物管理之中。 因此, 由于废弃物的数量减少, 降低了废弃物处理成本, 也提升了环保合符规定的程度。