The granulation characteristics of two quite different sinter blends have been studied. One comprises a significant proportion of pisolite ore, and the other is dominated by hematite ores. The effect on granulation of adding a significant proportion of West Angelas, a Marra Mamba type ore, into both blends is also studied. The relationship between blend moisture content and green permeability is measured, as is the size distribution of the granulated blends at different moisture contents. It is clear that when West Angelas ore displaces a denser, less porous ore type in a sinter blend, additional granulation moisture must be added to ensure optimal granulation performance. A petrographic study of granule morphology at different blend moisture contents is reported, with particular reference to the features of the adhering layer. The important role of ultrafines, particularly the Ϫ50 mm 'superfine' fraction, in the granulation process is discussed. The variations in mineralogical and textural characteristics of West Angelas ore with size are presented. It is proposed that the mineralogical and textural characteristics of the superfine particles are an important factor in the granulation performance of an ore or a blend of ores.KEY WORDS: iron ore; Marra Mamba; pisolite; hematite; granulation; sinter; permeability.the ore blend, it displaced all other ores in the same proportion. The 30 % West Angelas addition rate was chosen to ensure that a clear effect could be measured, but also with the consideration that rates of Marra Mamba use in sinter blends may well exceed 20 % in the future. For both Blends 1 and 2, introducing West Angelas increased the proportion of porous ore types in the blends.The calculated combined size distributions of the ore components of the four blends are shown in Fig. 1. Blend 1 is coarser, while Blend 2 has notably more material in the 0.063-0.5 mm size fraction due to the concentrate component. The addition of 30 % West Angelas does not have a significant impact on the sizing of either blend, though Blend 1 becomes slightly finer, while Blend 2 becomes slightly coarser. Granulation CharacteristicsThe quantity of moisture required to saturate each of the raw materials was measured using a simple gravity filtration technique. A 500 g sample was repeatedly saturated and then allowed to drain under gravity. The moisture content measured when drainage ceased was defined as the saturation moisture. The granulating characteristics of the four ore blends were examined by making up a number of sinter mixes from the component raw materials, including return sinter fines. The precise composition of the sinter mixes was calculated taking into account the ore blend composition, the sinter chemistry targets (4.9 % SiO 2 , 1.2% MgO, 1.8 CaO/SiO 2 ), the composition of the component materials and their inherent moisture level. Sinter return fines were added at a constant rate of 30 % of the ore blend.The effect of mix moisture on the granule properties was then investigated. The procedure involved varyi...