The requirements for an efficient process to generate finer particle sizes have led to advances in high energy mills. High performance milling media is needed to achieve the efficiency and milling objectives in high energy mills. The engineering advances in zirconia mill media to meet these needs are discussed. Results of laboratory and commercial case studies of media, mill wear, and milling efficiency in various high energy mill applications will be described. (c) 2006 Published by Elsevier Ltd.