Abstract: The disclosure is directed to a liner assembly for an autogenous ore grinding machine. The machine includes a large cylindrical drum which is rotated about a horizontal axis to comminute the ore. The liner assembly covers the inner cylindrical surface of the drum and consists of a plurality of longitudinal segments which are removably bolted to the drum. Each segment is made from a material which has good impact resistance and defines an irregular grinding surface to assist in the ore grinding process. An opening is formed through the segment body and extending longitudinally thereof, the opening being defined by walls that converge from the segment mounting surface to its grinding surface. A plurality of inserts, formed from material which is highly resistant to abrasion, are disposed in the opening and cooperate with the converging walls and each other in wedging relation for retainableengagement with the segment body bolted to the drum.