The use of electroacoustics as a method for determining the optimum dispersant dosage for the ultrafine grinding of limestone is presented. The technique measures the zeta potential of concentrated suspensions, hence it was possible to study the adsorption of three commercially available polyelectrolyte dispersants onto the limestone. The optimum dosage of the dispersants was determined and the most suitable one chosen for the grinding experiments. By utilising this optimum dispersant dosage, the productivity and throughput of a stirred vertical mill was greatly enhanced.