This study addresses the post-purification of reverse water by the electromagnetic focusing of charged particles in contaminants of polychlorinated biphenyls at mining enterprises. We established functional dependences of the Larmor radius of focusing of contaminant ions on operating parameters of the electromagnetic post-purification system (current strength of the focusing coil, length of the focusing coil), which allowed us to justify the required current of 0.025 A in the focusing coil for the post-purification of a liquid from polychlorinated biphenyls. The developed model of the electromagnetic system for water post-purification from the ions in contaminants made it possible to select the required Larmor radius for focusing the polychlorinated biphenyls in order to remove them effectively from a flow of liquid. As a result of post-purification, the contaminants are focused along the axis of the main flow that enables their removal through an additional branch pipe. Under the effect of the orbital moment that occurs due to magnetic induction, the motion vector of contaminants changed, and they are focused in the center of the fluid flow. We established the logarithmic dependence of height of the focusing paraboloid, which decreases from 0.057 m to 0.032 m with an increase in current of the focusing coil from 0.01 A to 0.1 A. This is due to an increase in the kinetic energy, transmitted by the charged particles, and an increase in the centripetal force. Determining the height of the focusing paraboloid makes it possible to effectively place the equipment for the removal of contaminations from the flow, and purify it