A mobile apparatus for comminuting lumpy material, especially rock, includes a chassis, a crusher arranged on the chassis, a feed device, provided on the chassis, for the lumpy material to be fed to the crusher and comminuted, a removal conveying device having a sieve device for the material comminuted by the crusher and a return conveying device for returning material held back by the sieve device to the feed device. In order to ensure heap separation of comminuted material of different grain sizes despite high crushing throughput, one conveying section of the return conveying device including at least two conveying sections is secured to the device by at least one rotational joint such that it can be turned away from the feed device.