A method of enriching the iron content of low grade iron ore bearing materials has been developed which produces a high iron ore concentrate suitable for processing into pig iron and steel. The process includes reducing the low grade iron ore bearing materials to a fine particulate form and treating a water slurry of this material by applying a combination of ultrasonic treatments in a plurality of high and low intensity magnetic separation operations to remove interfering materials and concentrate magnetic and paramagnetic iron bearing materials into a high grade ore stock.