Abstract: A method and apparatus for producing a coal/water mixture for combustion in a fluidized bed unit. To produce a hydraulically transportable coal/water mixture, crushed raw coal is preliminarily mixed with water in a first stage. This mixture is final mixed in a second mixing stage. The fine grain-size fraction required for the hydraulic transport is generated in the first mixing stage. The viscosity of the mixture present in the second mixing stage is determined, and as a function thereof additional water is added to the mixture in the second mixing stage, and/or the mixing process in the first mixing stage is altered in order to alter the fine grain-size fraction.