Abstract: A method of grinding material in a disc mill, the mill being operated at maximum r.p.m. corresponding to three to four times the critical velocity and is restricted only by injurious vibrations due to unbalanced masses so that the grinding material is centrifuged and forms a layer on the internal surface of the mill cylinder, the thickness of this layer being restricted by a suitable member. A disc mill for carrying out the method is also disclosed, the mill having free grinding discs of the same diameter, equal to about two thirds of the diameter of the mill cylinder, the discs being collected in an effective grinding area with a length about two thirds of the diameter of the cylinder.