The new CSIRO Hopkinson Bar Facility has been commissioned at the Queensland Centre for Advanced Technologies in Brisbane, Australia. Similar devices, such as the Ultra Fast Load Cell (UFLC) at the Utah Comminution Centre have proven to be extremely useful in providing fundamental breakage data of particulate material. In addition to its 19 mm and 60 mm diameter Hopkinson bars, the new CSIRO facility includes a large 100 mm Hopkinson Bar. This large diameter carbon steel load cell is instrumented with highly sensitive semi-conductor strain gauges that give it a force resolution of less than 100 Newtons, permitting precise measurement of the energy to fracture large mineral particles. The device＇s ability to measure breakage properties, such as first fracture force and energy, of large particles up 100 mm is unique. Breakage data for iron ores over a wide size range is presented. The well known comminution result of increasing particle strength and fracture energy with decreasing panicle size was confirmed for the iron ores tested. The influence of iron ore mineralogy and texture was also noted.