Blending in circular and longitudinal mixing piles

Both circular and longitudinal piles are used for blending raw materials in the cement industry. The materials are stacked in a great number of layers, and blending is obtained by reclaiming a mixture from all these layers. During the last 10 years, it has become common to mix a number of different materials in such piles. P. Gy pointed out more than 20 years ago that the Theory of Sampling (TOS) forms the basis of assessing the blending in a longitudinal mixing pile. The author pointed out more than 10 years ago that a similar, yet different theory can be developed for blending in a circular mixing pile. Based on these theories, purely numerical calculation tools that allow a person without knowledge of TOS to evaluate the obtainable blending in one of these mixing piles have been developed.