Dissolved inorganic carbon in drainage waters is a direct measurement of carbon dioxide (CO2) removal from enhanced rock weathering (ERW) in soils. In this study, square metre scale field experiments (2021–2023) were conducted in Peterborough Ontario, Canada, each amended with kimberlite residues from Gahcho Kué Diamond Mine (Northwest Territories, Canada) or olivine powder at high application rates (100–400 t/ha). Porewater chemistry data, coupled with a water budget analysis derived from precipitation and soil moisture data, were used to quantify solubility trapping by amendment weathering revealing maximum rates of 0.04 t CO2/ha over 2 yr for olivine and 0.9 t CO2/ha over 3 yr for kimberlite. This research presents kimberlite mine wastes as an ERW feedstock alternative to basalt as projects scale-up and require more rock. Additionally, high dosage monitoring plots ensure detection of a CO2 removal signal in open systems and should be considered for large scale projects.
Author Keywords: CO2 removal, Enhanced rock weathering, Field experiment, Kimberlite, Mine wastes, Olivine