As part of its mission to advance minerals technology, the federal Bureau of Mines has conducted investigations to determine the feasibility of producing subsieve-size material by an attrition grinding method. The Bureau-patented technique involves the intense agitation of a slurry composed of the material to be ground, a granular grinding medium, and a suspending fluid. Investigations were made to determine the efficiency of the method in grinding numerous industrial minerals, metals, and ceramic materials. The research has demonstrated the feasibility of the process for comminuting a variety of materials to extremely fine particle sizes. Transfer of this technology to industry has been achieved, and commercial-scale units currently are being used in the paper-coating clay and titania pigment industries.