This paper describes a research programme undertaken with a view to solving a serious industrial powder handling problem. The aim of this research was to rationalize three grades of an additive fine powder used in the manufacturing of a mixed product to one grade, with the aim of reducing or eliminating the potential risk of particle segregation within the product. The use of a segregation tester, specifically to quantify the propensity of a sample of bulk solid to segregate when poured on to a heap, was central to this research. Particular attention was paid to the particle size distribution curves of the final product within different areas of the segregation tester. Two different techniques for characterizing particle size were used in the investigation - one based on size separation using sieving analysis and the other based on the laser diffraction technique. These techniques yield different measures of particle size distribution, resulting in different conclusions as to the feasibility of particle size analysis being a useful indicator of the propensity of a powder to segregate.