Abstract: A grinding mill liner having inward and outward layers. The outward layer is formed of a relatively soft, shock-absorbent material and the inward layer is formed of a relatively hard, impact and abrasion resistant material. A plurality of magnets are embedded in the inward layer. A pair of pole pieces are positioned on opposed sides of each magnet and embedded in the inward layer. The pole pieces extend above the magnet, protecting it from the impact forces to which the liner is subjected during operation of the grinding mill. The pole pieces also focus the magnetic field forces emanating from the magnet. The magnets are arranged in rows, with adjacent poles of adjacent pairs of magnets within each row having alternate polarity; and, with adjacent poles of adjacent pairs of magnets in adjacent pairs of the rows having alternate polarity. The rows are parallel to one another and extend transversely to the direction in which material flows across the liner during operation of the grinding mill.