Abstract: The research urgency in the field of building materials is determined by crushing a large extent influenced by grinding on the technological properties of the material. The need to improve the dispersion of building materials in the form of the final product, as well as intermediate products in the processing steps required to create new and improved types of grinding units. This article describes the problems of grinding and classification. For the purpose of combining the above processes within a single unit, observing the principle of staging, grinding machine and material classification designed. Mathematical description of the processes of grinding and classification of materials were developed. The authors prove the need and opportunity to use methods of calculating the geometric parameters in the main nodes of the particle acceleration in the unloading of the machine grinding and classification of materials, taking into account the structural and technological features.