A crusher

A gyratory crushing apparatus (10) for frangible or friable material comprises: a bowl (104) having a chamber (104m) for receiving the material and a discharge opening (104j) disposed at the base with a central axis (101b) and a gyratory axis (101a) extending at an angle to the central axis (101b); a crushing head (102) and a drive assembly (103, 106). The discharge opening 104j) defines a throat with a circumferential wall (104k) and the crushing head (102) is disposed within the discharge opening. The crushing head (102) has a crushing face (102d) in spaced relation to the circumferential wall (104k) of the throat defining a nip between the circumferential wall and the crushing face (102d). The drive assembly includes a transmission (106) and a rotatable eccentric shaft (103) for driving the crushing head (102) within the bowl (104) and about the gyratory axis (101a) in a nutating motion. The bowl (104) also comprises a feed section and a discharge section, each defined by a wall (104b, 104d) and spaced by a mid-section, wherein thickness of a wall defining the mid-section (104c) is greater than a thickness of the discharge section wall (104d)