Abstract: A mill with capability for rapid replacement of wearable moving components and capacity for precision grinding movement. The wearable moving components form a package of dual counter-rotating rotor centrifugal devices, the packages including first and second motors (2, 5), counter-rotating first and second rotors (1, 4) driven by the first and second motors, respectively, a hollow shaft (6) connecting the first to the first rotor, and a solid shaft (3) connecting the second motor to the second rotor, the solid shaft running inside the hollow shaft.

Abstract: Integrated first stage and second stage reduction mechanisms reduce coal, minerals, biomass, and other materials. A portion of the reductive work is done in the first stage by passing centrally fed feed material centrifugally from rotating rings to counter-rotating rings with destructive effects. The resulting material, significantly reduced in size, subsequently is stripped of oversize in the second stage by passing through a closely spaced and specially contoured final pair of annular rings or crushing elements between which particles larger than the limited space are crushed.

Abstract: Integrated first stage and second stage reduction mechanisms reduce coal, minerals, biomass, and other materials. A portion of the reductive work is done in the first stage by passing centrally fed feed material centrifugally from rotating rings to counter-rotating rings with destructive effects. The resulting material, significantly reduced in size, subsequently is stripped of oversize in the second stage by passing through a closely spaced and specially contoured final pair of annular rings or crushing elements between which particles larger than the limited space are crushed.