Large-scale removal of carbon dioxide from the atmosphere is required to meet net-zero targets. Enhanced rock weathering, in which crushed silicate minerals are spread on cropland soils, is a promising approach, but the logistics of its supply chain are poorly understood. Here, we use a numerical spatio-temporal allocation model that links potential rock extraction sites in the United Kingdom with croplands, modelling deployment pathways over the period 2025–2070. We find that expanding individual quarries (up to 20 times larger than the current average) and prioritising supply timing and location can increase carbon-removal efficiency by 20%, cut transport demand by 60% and reduce the number of operating quarries four-fold, while enabling up to 700 million tonnes of carbon dioxide removal by 2070. However, these large sites may face stronger local opposition and planning challenges, underscoring the critical role of policy in enabling feasible deployment.