For vertical mills the dam ring height is often referred to as % of table diameter . The optimum height normally being in the range 2.5 - 4% of table diameter. Example: A dam ring of 120 mm in an Atox 32.5 will give a relative height of: 120 mm / 3250 mm = 3.7% Heat balance _ Example An example of a heat balance for a vertical mill Case: 200 t/h, 8 kWh/t(net), drying from 8% to 0.5% moisture IN Feed, dry