Modified carboxylic copolymer dispersant for fine- and ultra-fine mineral slurries. Designed to perform well at most extreme temperature and stress conditions in the calcium carbonate grind mills. Improves the efficiency of multiple-step grinding processes, from a coarse to a fine or ultra-fine ground calcium carbonate production, by providing lower viscosity than comparable dispersants. Provides better storage viscosity stability of mineral slurries at acceptable levels under elevated and room temperature storage conditions. Designed to enhance dispersion of mineral slurries by optimizing the different factors affecting dispersion, including polymer molecular weight, polymer composition and polymer structure.