The ability to predict the amount of fines produced during the transport and handling of lump iron ore is of particular importance to the iron ore supplier. This study combines simple contact and fracture mechanics approaches to derive a breakage equation for lump iron ore fractured in an ISO tumble drum, The tumble drum simulates the forces experienced by iron ores during relatively low impact handling and transport events. The results of tumble drum tests on three Australian iron ores of widely varying mechanical properties showed that the lump to fines ratio＇s predicted by the simple breakage equation were proportional to those measured experimentally. (C) 2000 Elsevier Science B.V. All rights reserved.