In 2004, LKAB decided to start a basic engineering study in expanding its existing production lines at the Malmberget mine site. Current limitations in the underground mine capacity entail the need to use ore from other mine sites which result in varying ore properties regarding grindability and chemical composition. It was necessary to determine if the required particle size from an agglomeration point of view could be obtained with extreme ore types by design in a robust process and a proper control strategy. In addition, project time constraints forced a decision of final design of the ore beneficiation process to be based on a combination of pilot scale campaigns and process simulations.