A coal washer of the classifier type whose agitator or rotator consists of hollow arms radiating from a central distributing manifold or center head. There may be four or more of these radiating arms, each with one or more downwardly inclined nozzles. When water is discharged from these nozzles, the impulse has the effect of rotating the agitator in a manner similar to a lawn sprinkler. This agitator is suspended in a cylindrical tank and water is pumped through it under pressure, thereby creating a controlled upward current uniform over the entire area of the tank.