Document Type : Original Research Paper
Authors
Dept. of Mining Engineering, Faculty of Engineering, Tarbiat Modares University, Tehran, Iran
Abstract
This paper proposes an integrated optimization–fuzzy multi-criteria decision-making framework to support the sustainable management of waste rock and tailings in an open-pit gold mine. Mine waste management is formulated as six mutually exclusive allocation scenarios (A₁–A₆), each specifying which overburden dumps and tailings storage facilities (TSFs) are available over a 12-month planning horizon divided into monthly periods. For each scenario, an optimization layer generates auditable operational plans using two linear programs: Model C, which minimizes controllable operating costs, and Model E, which minimizes a composite environmental impact index constructed from four routing-sensitive indicators—water consumption, haul-road dust emissions, TSF stability risk, and acid mine drainage potential. Uncertainty in inputs and qualitative assessments is represented using triangular fuzzy numbers and propagated via α-cuts. The resulting fuzzy performance matrix encompasses eleven criteria spanning economic, environmental, operational, technical, and social aspects; criteria are weighted using Fuzzy AHP, and alternatives are ranked with Fuzzy TOPSIS. Global robustness analysis, employing rank acceptability indices and structured stress-test scenarios, demonstrates that leading alternatives can exchange ranks under plausible uncertainty and that preferences may shift across regimes such as water scarcity or stricter acid mine drainage enforcement, supporting selection based on robustness and conditional optimality rather than a single deterministic ranking.
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