Slurry pump

A centrifugal pump comprising a volute casing, an impeller mounted to be rotatably driven within the casing, an inlet disposed to direct fluid generally axially from a feed line to the impeller, and an outlet disposed to direct fluid generally circumferentially to a discharge line, such that rotation of the impeller causes fluid from the inlet to be accelerated radially within the casing and discharged circumferentially from the outlet at increased pressure, said impeller including a plurality of vanes disposed intermediate a pair of spaced apart side walls, at least one of said side walls having a substantially smooth generally planar outer surface and a plurality of channels recessed into said surface, each said channel spiralling progressively outwardly and rearwardly relative to an intended direction of rotation and having a cross sectional flow area reducing substantially uniformly from a central region towards a respective rearwardly directed peripheral discharge port.