Comparison between the application of the conventional mine planning and of the direct block scheduling on an open pit mine Project

Abstract Historically, since the 60's, traditional mine planning consists of several distinct stages: 1) Definition of the ultimate pit - the portion of the blocks that results in the greatest total value; 2) Pushback selection - based on the generation of nested pits, obtained with the change in the value of the ore price; 3) Long-term production scheduling. Although considered quite satisfactory, this methodology presents some flaws: The stages, even if considered individually optimal, may not be when put together. The opportunity cost is not considered and the cut-off is fixed. Due to the recent computational advances, a new technique has been growing and is more reliable: the direct block sequencing. In this methodology, the steps are consolidated into only one process, improving the economic results, reducing the total execution time and obtaining, in fact, an optimal planning. The aim of this work is to compare the results of the two planning methods applied in a database of a Brazilian iron ore mine and to show the real advantages and disadvantages of each one. To solve the direct block sequencing technique, Doppler was used, a tool developed by Delphos Mine Planning Laboratory, located at the University of Chile. The traditional methodology was executed through Whittle software. Lastly, a medium-term scheduling was performed using Deswik software.

摘要 自20世纪60年代起，传统矿山规划通常包含三个独立阶段：1. 最终开采境界（ultimate pit）确定：选取可实现总价值最大化的矿块区域；2. 分段推进方案选择：基于矿产品价格变动生成的嵌套开采境界（nested pits）制定规划方案；3. 长期生产计划编制。尽管该方法整体表现尚可，但仍存在若干缺陷：各阶段即便单独实现最优，整合后未必能达成全局最优；且该方法未考虑机会成本，截止品位（cut-off）固定不变。随着近年来计算技术的进步，一种更可靠的新兴技术正逐步发展：直接矿块排序（direct block sequencing）。该方法将所有规划步骤整合为单一流程，可提升经济效益、缩短整体执行时长，并最终得到全局最优的矿山规划方案。本研究旨在对比两种规划方法在某巴西铁矿数据库中的应用结果，并阐明二者各自的实际优劣。针对直接矿块排序技术的求解，本研究采用了智利大学德尔福斯矿山规划实验室（Delphos Mine Planning Laboratory）开发的Doppler工具；传统规划方法则通过Whittle软件实现；最后，本研究还借助Deswik软件完成了中期生产计划编制。