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• CO 2 fluxes were measured using a variety of feedstocks that are applicable to enhanced weathering including kimberlite, brucite, forsterite, serpentinite, and wollastonite. • Mineralogical composition and reactivity had the greatest impact on CO 2 drawdown. • Negative fluxes of -2940 g CO 2 /m2/yr were achieved using highly reactive brucite. • CO 2 removal rates of -870 g CO 2 /m2/yr (1.5% offset in mines emissions) were achieved for mine residues when labile Mg is present. • Mine waste management practices that enhance exposure will lead to greater CO 2 removal. Enhanced rock weathering (ERW) sequesters CO 2 via solubility and mineral trapping and can be implemented by the mining industry to reduce their net greenhouse gas emissions. Kimberlite residues from Venetia Diamond Mine in South Africa, as well as powdered forsterite, serpentinite, wollastonite skarn, and 10 wt.% brucite mixed with quartz sand, were tested as potential feedstocks for ERW. A CO 2 flux system directly measured CO 2 removal rates and sensors tracked laboratory conditions and pore water saturation during a series of 2-week experiments. With respect to kimberlites, unweathered residues achieved the greatest drawdown rate of -870 g CO 2 /m2/yr at 48% saturation. In contrast, fine and coarse residues previously exposed to mine process water achieved fluxes of -150 and -160 g CO 2 /m2/yr at 60% saturation. Brucite reached -2940 g CO 2 /m2/yr at 14% saturation compared to forsterite, serpentinite, and wollastonite that achieved fluxes of -500, -260, and -190 g CO 2 /m2/yr, respectively, at higher saturations of 53–60%. Mineralogical composition had the greatest effect on CO 2 fluxes, followed by water content which drives carbonation reactions and affects permeability. Solid inorganic carbon increased in the brucite, wollastonite, and unweathered kimberlite, indicating that CO 2 was stored via mineral trapping as opposed to solubility trapping in the other experiments. Increasing the exposure of unweathered residues, expanding dispersal area, and optimizing water saturation would lead to greater CO 2 removal at mine sites. [ABSTRACT FROM AUTHOR]