A method and apparatus for transporting a product within a diffuser during a continuous lixiviation process. The apparatus comprises at least one screen deck for the continuous lixiviation process and at least one longitudinal transport zone, the longitudinal transport zone extending between an inlet and outlet of the diffuser. The transport zone may include a plurality of transport zones. A drive means is arranged to move the longitudinal transport zone at a first speed towards the outlet end of the diffuser and to retract the longitudinal transport zone at a second speed which is substantially faster than the first speed towards the inlet end of the diffuser, so that the transport zone drive the product towards the outlet of the diffuser.