Abstract: A mixture of rock, soil particles and wood pieces (10') is introduced into a water tank (34) generally between a manifold (64) for a plurality of jet nozzles (62) and a vane or baffle (66) towards which the nozzles (62) discharge streams of water. Buoyant and nonbuoyant wood pieces (14) are moved by currents produced by jet streams issuing from the nozzles (62) towards and over the baffle (66) onto a wood piece conveyor (150) which removes the wood pieces (14) out from the water tank (34). Rocks (16) from the mixture drop down onto a rock receiving portion (82) of a rock conveyor (82, 84) which collects the rock (14) and removes it out from the water tank (34). Soil particles (18) from the mixture are washed off from the rock (16) and wood pieces (14) and settle to the bottom of the tank (34). A drag chain conveyor (160) moves accumulated soil particle mud out from the bottom of the chamber (34).