Ball mills

Stirred ball mills which have a casing that houses serially related sets of elongated, longitudinally extending stirring elements. The elements of each set are supported in a concentric array about and from a rotatable shaft. Complementary arrays of stirring elements may be supported from the casing, and it and the shaft can be rotated in opposite directions to optimize the stirring of the grinding balls in the mill. Also, concentric arrays of stirring elements may be assembled to the shaft or the shaft and the casing for this purpose. The stirring rods also cause the grinding balls to scour and thereby prevent plugging of a screen located at the discharge end of the mill to keep the grinding balls from escaping. The mill can be tilted in a manner that results in the grinding balls being uniformly distributed along the length of the casing.