Economic and environmental right-sizing of battery-electric haulage fleets in open-pit mines

This paper presents a flow-based optimisation framework for right-sizing battery-electric vehicle (BEV) haulage fleets in open-pit mines and assessing their economic and environmental performance against a diesel baseline. Fleet design is formulated as a mixed-integer linear program (MILP) over an extended state network that captures truck load state, battery state of charge, production targets, charging-station capacity, and endogenous traffic congestion through delay curves calibrated via Bayesian inference. For each candidate truck class and battery capacity, the framework optimises fleet size and flows, then evaluates operational electricity-related CO 2 e emissions, battery embodied emissions, active-fleet battery capacity, and installed charging capacity within a stated environmental boundary. Experiments on three mine-scale maps show that omitting charging or congestion underestimates fleet cost and that cost-minimising designs need not be the lowest-emission alternatives in the evaluated design grid. Under the model-consistent diesel baseline and base grid-emission factor of 0.25 kgCO 2 e/kWh, the class-matched BEV designs reduce operational CO 2 e by 61.7%–63.5% (57.4%–62.4% including battery embodied emissions). The operational break-even grid intensity is 0.653–0.685 kgCO 2 e/kWh. Electrification also avoids the associated local NO x , particulate-matter, and black-carbon emissions. Under the base cost coefficients, these reductions come at a small, infrastructure-conditional cost premium of about −1% to ＋7.4% relative to the diesel cost minima. This range covers class-matching and charging-infrastructure-cost scenarios, and the BEV fleets require 7.5%–18.2% more active trucks. All results derive from synthetic mine layouts, a simplified traction-energy model, and a model-consistent rather than field-calibrated diesel baseline. The environmental accounting is a bounded CO 2 e evaluation rather than a full life-cycle assessment. These findings highlight the need to consider truck class, battery capacity, charging infrastructure, congestion, and electricity carbon intensity together when designing cleaner battery-electric haul fleets.