Abstract: This disclosure relates to deep sea mining apparatus, comprising a relatively straight lift pipe, the lift pipe being adapted to extend substantially vertically from the floor of a body of water upwardly to a ship on the surface of the water. A plurality of jet pumps are connected in the pipe at intermittent locations along the length of said pipe, and a hydraulic feed pump is located adjacent each of the jet pumps and is connected to discharge water in its location and to supply the associated jet pump. Means is also provided for injecting compressed air into the jet pumps, the jet pumps thereby forming an ascending current inside the lift pipe by the introduction of the compressed air and water.