Comparative analysis of mathematical models for integrated production scheduling and sustainable waste management in open-pit mining complexes

Optimal production scheduling and waste management in open-pit mining operations present significant challenges. The conventional two-step process involves the application of mixed-integer programming (MIP)-based models to sequence the extraction of mining ore blocks over a planning horizon, followed by a separate procedure to allocate extracted waste blocks to various locations within waste dumps. This paper introduces an integrated approach to optimise extraction sequencing and waste dump management in a mining complex comprising multiple pits or mines, multiple material processing streams, stockpiles, and waste dumps. In addition to addressing critical operational and technical requirements, the proposed approach ensures the environmentally responsible disposal of potentially acid-forming (PAF) waste and incorporates explicit control of haulage costs, enhancing material transport efficiency and reducing the carbon footprint coupled with greenhouse gas (GHG) emissions in line with an environmental, social and governance (ESG) principles. The study employs mixed-integer linear programming (MILP)-based models, including both existing and newly developed formulations, to achieve simultaneous optimisation of pit production and waste dumping plans. A comparative analysis of these models, applied to an operational mining complex in Western Australia, highlights the novelty of this contribution in terms of model structure, computational complexity, solution efficiency, and environmental sustainability.