Abstract: Apparatus for separating relatively large undesirable particles from a slurry includes an endless movable filter belt mounted for movement along a horizontal path and supply means depositing slurry carrying large particles on the upper surface of the filter means. Pressurized gas jets are positioned beneath the lower surface of the filter means in the area beneath which the slurry and relatively large particles are deposited to agitate same and suction means beneath the filter belt to separate the slurry from the relatively large particles to provide purified slurry. Gas from the slurry is separated by a degasser having a spiral floor partition which slurry comprises drilling mud and said large particles comprise earth cuttings comprises a common wall between gas and slurry outflow conduits in a space-saving manner.