Abstract: A tub grinder apparatus having a base providing a tub floor, a generally cylindrical shaped wall providing a tub side having an open top edge and an open bottom edge and being mounted on the base with the bottom edge spaced above the tub floor the mounting allowing for rotation of the tub side relative to the tub floor about a first axis, the top edge providing a substantially cylindrical top rim lying in a substantially horizontal plane and providing a top loading entry port, a grinding device mounted on the base for rotation about a second axis, the second axis being located below the upper surface of the tub floor, the grinding device having material comminuting segments mounted to move along a closed path as the grinding device is rotated about the second axis, a first portion of the closed path extending through the opening in the tub floor and above the upper surface whereby material on the tub floor within the grinding cavity can be moved over the upper surface of the tub floor into the first portion o