On the Use of Evolutionary Optimization for the Dynamic Chance Constrained Open-Pit Mine Scheduling Problem

TL;DR

This paper presents a bi-objective evolutionary approach with a diversity-based change response mechanism to effectively solve dynamic, uncertain open-pit mine scheduling problems, outperforming baseline strategies.

Contribution

It introduces a novel diversity-based change response mechanism for evolutionary algorithms addressing dynamic, uncertain mine scheduling, improving solution feasibility and quality.

Findings

The proposed method outperforms baseline strategies across multiple instances.

It maintains higher solution diversity during dynamic changes.

The approach is effective under various uncertainty levels and change frequencies.

Abstract

Open-pit mine scheduling is a complex real world optimization problem that involves uncertain economic values and dynamically changing resource capacities. Evolutionary algorithms are particularly effective in these scenarios, as they can easily adapt to uncertain and changing environments. However, uncertainty and dynamic changes are often studied in isolation in real-world problems. In this paper, we study a dynamic chance-constrained open-pit mine scheduling problem in which block economic values are stochastic and mining and processing capacities vary over time. We adopt a bi-objective evolutionary formulation that simultaneously maximizes expected discounted profit and minimizes its standard deviation. To address dynamic changes, we propose a diversity-based change response mechanism that repairs a subset of infeasible solutions and introduces additional feasible solutions whenever a change is detected. We evaluate the effectiveness of this mechanism across four multi-objective evolutionary algorithms and compare it with a baseline re-evaluation-based change-response strategy. Experimental results on six mining instances demonstrate that the proposed approach consistently outperforms the baseline methods across different uncertainty levels and change frequencies.