The data of experimental research into mechanical properties of limestone, hornfels and sandstone cores after treatment by accelerated electrons show that the irradiation changes the strength and deformation characteristics of the tested rocks. In limestone and hornfels, uniaxial compression strength and elasticity modulus decrease, and ratio of P- and S- wave velocities changes; in sandstone tensile strength decreases, while uniaxial compression strength, P- and S-wave velocities and dynamic Young’s modulus grow. Modification of the minerals after accelerated electron irradiation opens ways of creating efficient energy-saving technologies for pre-treatment and processing of complex ores.