Abstract: A crushing machine including a crushing means, a feed conveyor for feeding material to the crushing means, a detector for detecting metal in the material on the feed conveyor, and a bypass chute for the crushing means, the feed conveyor being movable between a normal operating position in which the material is fed to the crushing means and a bypass position in which the material is fed to the bypass chute, the arrangement being such that on detection of metal in the material, the feed conveyor is stopped and moved from the normal operating position to the bypass position so that the material with the metal is discharged into the bypass chute.