Abstract: A process for impact crushing of rock and ore lumps, in which a rock lump is subjected to a primary impact force P.sub.1, and then the plurality of resultant smaller pieces are subjected to a secondary impact force P.sub.2. The application of the impact forces P.sub.1 and P.sub.2 is synchronized in time. The velocity vector V.sub.1 of the lump subjected to the primary impact force P.sub.1 and the vector of the secondary impact force P.sub.2 lie on a line running through the center of the lump mass. The invention also covers an apparatus for performing the above process, which comprises a housing accommodating a primary crushing rotor and a secondary crushing rotor, and also means for synchronizing the rotation of the secondary crushing rotor and the primary crushing rotor, coupled kinematically to said rotors. The secondary crushing rotor has two hammers, and its mass increases along the longitudinal axis of symmetry in a direction away from the axis of rotation.