Experiments were conducted to determine the effects of fill level, mixing time, and use of baffles on the mixing performance of a pilot plant scale tote (bin)-blender. The binary mixture under study was free-flowing, noncohesive art sand of two colors. Mixture uniformity was evaluated by sampling the blend using core samplers with the samples quantified by image analysis. The rate of mixing was significantly affected by the degree of blender fill. Four fill levels were examined, 20% fill (fastest), 40% fill, 60% fill (optimum), and 80% fill (slowest). Top-bottom and side-side initial loading patterns were studied to determine the influence of the axial and radial mixing mechanisms with and without an internal baffle at the manufacturer's standard position. Axial mixing was found to be the rate-limiting step to achieving overall blend homogeneity. The standard baffle configuration only generated moderate enhancements in mixing. A first-order mixing model was applied to determine the mixing rate constant for the various fill levels and baffle conditions investigated.