Abstract: A crushing machine comprises a pair of crushing rolls which are designed to be rotatable towards each other and away from each other. A side plate is provided on the outside of each roll. The crushing rolls have teeth which are shorter than conventional crushing teeth. The teeth on each roll are aligned with each other to provide cavities in which the crushing can occur. Rotation of the crushing rolls towards each other provides a centre sizing action to crush material (e.g. coal) into a larger particle size. Rotation of the crushing rolls away from each other provides a side sizing action to crush material between the roll and the side plates to a smaller particle size. Thus, the machine can crush material into two distinctly different particle sizes without any modification being required to the machine, the dual sizing occurring by reversing the rotation of the rolls.

Abstract: A crushing roll which has teeth which are replaceable on the roll body, and where are the teeth or picks can be removed individually from the periphery of the roll body. The picks can be attached to a holder, and the holder can be removably attached to the roll such that the picks and the holder can be removed from the roll in an individual manner. The holder can be designed to also protect the surface of the roll to reduce damage to the roll surface.

Abstract: A method for reducing fines generated during a crushing operation comprises matching the peripheral roll speed to the drop velocity into the crusher of the material to be crushed. The method is particularly suited to high volume crushing coal where existing techniques result in the generation of a significant level of coal fines (−4 mm).