Coordinated sizing of battery and charging systems for underground mining electric trucks

The heavy reliance on diesel-powered haul trucks in underground mines contributes substantially to CO 2 emissions and poses significant health risks to workers. Electrification of haul trucks offers a promising way to address these challenges, yet designing charging system in this constrained environment involves complex trade-offs between cost, productivity, and technical feasibility. This paper presents a novel optimisation-based framework for the coordinated sizing of onboard batteries and charging systems in underground operations, explicitly considering the interactions between battery size, payload capacity, charge rate, battery degradation, and regenerative braking. Three charging technologies, including fast charging, battery swapping, and trolley-assist, are systematically compared using tailored design models through rigorous net-present cost analysis over the mine’s operational life. The framework assesses how essential operational elements, such as the minimum viable battery capacity, frequency of charging cycles, length of the trolley, and motor efficiency, impact cost and productivity results. Simulation results for a hypothetical mine reveal distinct Pareto-optimal frontiers for each charging technology, highlighting how optimal choices shift under varying technical and economic conditions. This framework provides mining planners with a quantitative basis for selecting charging strategies that balance capital and operating costs with sustained productivity. • Joint sizing of battery capacity and charging system power for underground haulage. • Nonlinear optimisation developed for fast-charging and battery-swapping system design. • Linear optimisation developed for designing trolley-assist charging systems. • Techno-economic comparison including battery ageing and mine-life cost evaluation.