Results of an analysis of a power unit equipped with fan mills, medium-speed and hammer mills are presented. It is shown that, from the point of view of explosion risk safety, availability and efficiency of the block for furnaces with solid slag removal, a system of p. f. preparation with direct blowing-in and medium-speed mills is optimal. For furnaces with liquid slag removal, a system of p. f. preparation with an open drying circuit and an intermediate storage bunker, equipped with medium-speed or hammer mills is recommended.