a centrifugal separator for gold or the like is of the type in which a bowl is rotated at high speed so that materials fed into the bowl pass over the peripheral wall of the bowl to an open mouth . on the inner surface of the bowl is provided a series of ribs defining peripheral recesses in which the heavy material is collected . an outer shell surrounds the bowl and defines with it a chamber into which water is injected to pass through openings at the base of the recesses to fluidize the material within the recesses . the outer shell has a peripheral wall of increasing diamter toward the open mouth with a plurality of openings being provided in the shell around to open mouth to allow the escape of silt collecting in the chamber . a wear resistant plastics material is attached to the bowl at the open mouth and to a casing surrounding the open mouth to redirect the exiting materials to an outlet duct . a plug for the base of the bowl can be latched into place by a pivotal latch member actuated by centrifugal force caused by rotation of the bowl to prevent loss of the plug under the high forces generated during the rotation .