The effects of an enhanced weathering intervention should be understood as the difference between the observed carbonate formation and the carbonate formation that would have occurred absent the intervention. The baseline rate of carbonate formation may be strongly dependent on the physical characteristics of the feedstock (e.g. surface area and grain size distribution), environment (e.g. mine design, climate, weather) and treatment of the alkaline waste material, in the present and future. In some systems, the baseline may be best characterized by ongoing measurements of an untreated control.