Energy Use of Fine Grinding in Mineral Processing 18 12 2013· The smallest ball size typically charged into ball mills and tower mills is ½ inch mm although media diameters as small as 6 mm have been used industrially in Vertimills In a laboratory study by Nesset et al [ 7 ] a GIS mill charged with 5 mm steel shot and with other operating conditions similarly optimized achieved high energy efficiencies when grinding