A series of patented processes originally developed for the concentration of ore, but finding increased usage in coal cleaning. Suspension of magnetite (sp gr, 5.0) and ferrosilicon (sp gr, 6.7) are usually used for ore concentration; suspensions of magnetite for coal. The basic features of these processes as applied to coal are in the methods used for handling the magnetic medium. Specifications for magnetite should be somewhat as follows: l00% -100 mesh, 65% to 75% -325 mesh, 85% magnetics, and wet-ground in a ball or rod mill.