... used in selection of Tin, tungsten, gold, silver, lead, zinc, tantalum, niobium, iron, manganese, ferrotitanium and coal ... , covered with riffles (raised bars running perpendicular to the feed side of the table), mounted in ... the low SG particles will work their way to the top, where they will be carried along ... a difference in specific gravity of the materials needs to be significant, at 1 or greater. I. ...