Abstract: A slurry feed pump which delivers a highly pressurized suspension of coal particles, coal oil and a catalyst to a liquefaction reactor is installed in a plenum chamber which is filled with pressurized coal oil and surrounds the pump housing. The suspension-supplying conduit sealingly extends into the chamber and is connected with the inlet of the pump housing, and a second conduit which delivers pressurized suspension to the reactor sealingly extends into the plenum chamber and is connected with the outlet of the pump housing. The pump is a vertical cantilevered centrifugal pump which is operated below first critical speed and its housing has holes for admission of coal oil from the plenum chamber to those parts in the pump housing which are most likely to undergo extensive wear under the action of coal particles in the suspension.