Abstract: A mineral jig for use in treatment plants for the concentration of heavy minerals e.g. cassiterite, gold, platinum, garnet, pyrites and magnetite includes a container for water comprising an upper substantially cylindrical portion and a lower frusto-conical plunger portion, the container including an inlet for water and an outlet for concentrated slurry. A rotor of dished or inverted frusto-conical form is mounted for rotation in the upper portion, and carries a screen of wire mesh or perforated metal. A drive is provided for vertical oscillation of the plunger and a water seal is located between the portions. In operation, slurry on the rotor is subjected to pulsations as a result of the plunger oscillations and to centrifugal force causing a vortex to form in the container co-axial therewith. Heavy mineral passes through the screen and is concentrated prior to collection, while lighter metals move up the rotor and eventually spill over the edge thereof for subsequent collection.