Drum magnetic separators constitute the most common type of separators applied in the magnetic ore enrichment processes and in dense-medium recovery in the systems of gravitational enrichment in heavy medium suspensions. The separation effects depend on many factors, such as separator efficiency, content of solid parts in the suspension, magnetic field intensity in the separator working space, drum rotational speed, feed particle size and distribution of magnetic properties in the feed. Due to the phenomenon of magnetic flocculation, multiple cleaning or supplementing separations are used to obtain products of fixed quality. In the paper, by means of solving Laplace's equation in the polar system (Eqs 1 and 2), the author determined the characteristics of the working space in the magnetic separator in the form of magnetic field distribution (Eqs 9 and 13) and magnetic force acting upon the particle (Eqs 15a and 15b), determined the optimum value of pole pitch of the separator magnetic system (Eq 23). The dependence of pole pitch on particle size for two values of the drum radius was presented in Fig. 3. The value of magnetic separation susceptibility at dry enrichment was calculated from the force balance together with the content of magnetite in separation particles (Eqs 27 and 29, respectively). The model of multiple separation in the continuous process was elaborated in order to execute the separation analysis, obtaining a general expression for the recovery of magnetic particles in the magnetic products after several supplementing separations of the non-magnetic product (Eq 42) as well as the dependence of the content of magnetic component in the non-magnetic product upon the length of separation path in a single stage (Eq 50). In equation (42) and (50) denotes the separation rate constant of magnetic particles. Applying the empirical dependence of content of the magnetic component in the non-magnetic product upon the number of drum rotations the author, according to the model, determined the dependence of separation rate constant of the magnetic components upon the number of drum rotations. Figure 8 presents this dependence. The analysis of separation, presented in this article, is based upon heuristic considerations. Magnetic interactions between particles should be taken into account when calculating the dependence of the separation rate constant of the magnetic component upon the process efficiency. On the other hand, in order to determine the dependence of the separation rate constant upon the number of drum rotations, the separation process should be considered as a birth and death stochastic process in the continuous separation system.