The present invention relates to a method for producing pumpable coal-water suspensions by grinding pre-comminuted coal with water in a packed column in a ratio corresponding to the composition of the suspension ready for use. The addition of water or coal is controlled by measuring the density of the suspension leaving the mill, and the grain size of the coal particles is controlled by measuring the viscosity of the suspension. The density and viscosity of the coal-water suspension are simultaneously mutually adjusted. The addition of additives to the water is regulated according to the amount of coal added to the mill. The coal-water suspension can be fed to a coal gasification reactor without substantially changing the relative amounts of coal and water in said suspension.