A sink-float process in which the medium is a suspension of clay from the raw coal and minus 200- or 300-mesh barite in water, with the volume of the clay usually equal to about twice that of the barite. Barite clay and coal suspensions can be regulated to get effective washing gravities from 1.2 to 1.8. Sizes from run-of-mine to one-eighth inch may be cleaned by this process, which has been widely adopted in Europe. Also known as the Sophia-Jacoba process in German publications.