In the mountain industry a considerable part of technological processes are followed by loadings of bulk in various capacities and the bunker. When loading bunkers of silage type self-dumping carts the problem of knocking-out of dust from loading apertures is particularly acute especially. Work is devoted to improvement of methods of calculation of aspiration when loadings bunkers of silage type by polydisperse material. New statistical approach to the accounting of conditions of constraint on coefficient of front resistance of particles in the conditions of a free stream of the falling material is offered. When falling a free stream of material of a particle of larger fractions shade small and dust particles which aerodynamic resistance in such conditions isn´t considerable. Analytical conclusion of probability of active impact on air of the particles which are out of an aerodynamic shadow that allows to receive a technique of assessment of ezhektiruyushchy ability of a stream of particles at dust removal of bunkers of silage type has been offered. At further development of this approach a conclusion of probability of aerodynamic interaction of particles of polydisperse material is possible. The accounting of dispersion of the overloaded material will allow to calculate optimum amount of aspiration air and to reduce energy consumption of systems of aspiration.