This work is dedicated to the theoretical study of the minerals benefication by a new method: magnetic jigging. The idea beyond magnetic jigging is to use both magnetic and gravity fields for fine particles separation. To solve this task the following problem was stated and resolved: development of a mathematical model which adequately describes the dynamics of magnetic jigs, bed dynamics and the separation process. During the numerical solutions and analyses of the developed mathematical model for batch jigging the following results and conclusions were obtained: (a) the mathematical model adequately describes the familiar jigging regimes; (b) the superposition of the gravity and relatively weak magnetic forces principally changes the character of jigging; (c) the superposition of the gravity force and relatively weak magnetic forces gives the ability of separation of ＇difficult to beneficate＇ mixtures.