An impact processing system (10) having a central opening (12) enabling material flow into a primary impact zone (14) in which is located an impact mechanism (16) rotatable about a rotation axis (18). An impact structure (20) provided with a plurality of holes (22) surrounds the impact mechanism (16). The rotatable impact mechanism (16) impacts material entering the primary impact zone (14) from the central opening (12) and accelerate the impacted material in a radial outward direction toward the impact structure (20) to effect fragmentation of the impacted material so that when sufficiently fragmented the material is able to pass through the holes (22). An optional outer structure (30) is radially spaced from the impact structure (20) and may comprise one or more segments that cumulatively extend about the axis of rotation (18) for an angle from 30 and 270 inclusive. A rotatable set of impact members (50) may be located between the impact structure and the outer structure. One or more gaps (28) may be provided in the impact structure (20) to allow the passage of large and/or hard objects that cannot otherwise be fragmented. The outer structure (30) is positioned to span across the gaps (28) so that material passing there thought is directed onto the outer structure (30).

A multistage hammer mill 10 has a plurality of milling stages arranged concentrically so that substantially all material in a first innermost of the milling stages passes through all subsequent adjacent milling stages. A central feed opening 12 enables material flow into a primary impact zone 14 of a first milling stage, which has an impact mechanism 16 and a first screen arrangement 20a. The impact mechanism 16 rotates about a rotation axis 18. The first screen arrangement 20a is disposed circumferentially about and radially spaced from the impact mechanism 16 and has a plurality of apertures 22 through which impacted material of a first size range can pass. A second milling stage has a second arrangement 20b disposed circumferentially about and radially spaced from the first screen arrangement 20a and a circular array of impact elements 50a between the first and second screen arrangements.

An anvil assembly for a vertical shaft impact rock crushing machine includes a plurality of anvils and anvil holders, each anvil holder including an anchor plate and a buttress wall, the anchor plate having dual tapered shoulders and the buttress wall extending perpendicularly from one side of the anchor plate. The rear face of each anvil includes dual vertically-mirroring docking ports each having dual, inwardly-oriented, angularly inclined side channels. In a mounted configuration the shoulders of each anchor plate are detachably captured in the side channels of one of the docking ports, thereby supporting each anvil on the anvil holder and securing it to the crushing machine.

An impact mill (10) has an inlet (12) for material to enter the mill, an impact mechanism (16, 50) arranged to rotate about a rotation axis and being operable to pulverise the material after entering through the inlet, and an outlet (154) for discharge of pulverised material. Blockage sensors (Bj), vibration sensors V, torque sensors Tn, temperature sensors and proximity sensors may be selectively incorporated into the mill.

A shell liner for a stirred grinding mill is configured to be releasably fitted to the inside of a shell of the mill within a grinding chamber thereof. At least a part of a surface of the shell liner that is configured to be exposed within the grinding chamber constitutes a wear surface. The shell liner includes at least one polymer-ceramics panel having an elastic material layer and wear resistant inserts retained by the elastic material layer. Exposed surfaces of the wear resistant inserts form part of the wear surface of the shell liner.