The aim of this paper is to define the range of utilisation of a new pneumatic pilot plant mixer. We report the validation of the mixing performances and efficiency for a binary mixture of cohesive powders, lactose monohydrate as excipient and salicylic acid as tracer. We studied the effect of the fill levels (25%, 50% and 90%) and tracer concentrations (0.01%, 0.1%, 1% and 10% w/w) obtained without pre-blending on the blend homogeneity (relative standard deviation) and the mixing time. We also investigated the effect of the sampling size (30 g vs 1 g) on the stochastic homogeneity of 2% (w/w) salicylic acid blends with an automatic sampling device. The fill level has only a slight effect on the mixing performances of the mixer with 30 g samples. Moreover the different target concentrations were obtained in a single blending step in less than 6 min. Most of the related RSD were beneath 7%. A smaller sample size of 1 g showed a greater variation in the limits of +/- 10% of the target value. This mixer is a good alternative to most batch mixers used at the time in the pharmaceutical industry. Nevertheless, as assumed, we confirmed the crucial impact of the scale of scrutiny. (C) 2012 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.