Friable particulate material is crushed and classified by apparatus comprising a grinder apparatus operatively positioned in the hollow interior of a relative rotationally mounted container. The grinder apparatus preferably comprises three rotationally mounted cone wheel roller members, each of which includes an outer grinding surface of predetermined contour. The outer grinding surface of each of the roller members maintains substantial conformance with a grinding face of the cylinder container from a center area to an outer edge of the grinding face as the roller members rotate. Feed particles of friable material and a continuous supply of fluid are introduced into the container and diffused substantially over the whole grinding face. Once the feed particles have been crushed to a predetermined size, the crushed particles are carried away from the grinding face by the flow of fluid exiting the hollow interior. The fluid velocity is controlled to remove a predetermined range of size of crushed particles from the grinding face and to separate or classify the removed crushed particles according to size and weight.