Enhanced gravity separation device using closely spaced channels

An enhanced gravity separation device rotates a plurality of rectangular section vessels (2) about a central drive shaft (1). Each vessel has an array of closely spaced plates (8) positioned with the vessel between outer regions (6) and inner regions (7). A feed of mixed dense and less dense fluid matter is fed to the outer regions (6) via a pipe (1a) and conduits (21), through the plate arrays (8) and into the inner regions (7). Overflow of less dense matter reports to the inner regions (7) and underflow of denser matter reports to the outer region (6). The vessels may be fluidised by liquid supplied into the outer regions (7) via annulus (14A) and conduits (14).