A crusher apparatus includes a crusher device having an inlet for receiving a supply of crushable bulk material, and an outlet for discharging crushed material; and a feeder device arranged to feed the supply of bulk material to the inlet of the crusher device in which the feeder device is adjustable between an operative feeding position in which the bulk material can be supplied to the inlet of the crusher device, and an inoperative position to discharge the material, without being fed to the crusher device, e.g. when undesirable material is present in the material for supply to the crusher device.