Abstract: A device for processing materials such as rock, ore, clay, bulk materials and agglomerated pulverized materials includes at least two tools having working surfaces thereon of at least partially circular cylindrical cross section. The tools are oriented such that the working surfaces thereof are in opposed horizontally spaced relation, and the device includes a mechanism for moving at least one of the tools with an up and down pendulum motion about the respective axis thereof. The tools include upper surface portions and lower surface portions, and the upper surface portion of at least one of the tools has a plurality of comminuting projections thereon for preprocessing relatively large sized materials. The lower surface portions of the tools are substantially smooth, and they are positioned in closely spaced relation for processing materials therebetween to form a finely milled and product.