Abstract: Improvement in undersea mining apparatus, of the kind wherein a hydraulic suction conduit riser is towed from a forwardly moving surface ship while a mixture of liquids and sea-floor solids (such as sea water and manganese nodules) is gathered at the deep sea floor and transported to the sea surface in a liquid-solids flow pumped up through the riser, comprises liquid-solids flow transition chamber that is connected to riser by an intermediate conveyance duct and towed along the undersea floor to gather and transmit solids from undersea floor to riser. Transition chamber has three mutually communicating openings: a forward-facing entrance for gathering sea floor solids, a rearward-facing entrance for admitting a hydraulically induced flow of sea water and a forwardly upward-facing exit port joined with the conveyance duct to direct transmission of liquid-solids mixture flow from chamber into conveyance duct.

Abstract: Vehicle constructed for being towed along undersea floor area where desired mineral aggregates, such as manganese nodules, are dispersed on ocean bottom carries apparatus utilizing power from towed motion, hydraulic suction and vehicle-borne motor for acquiring, concentrating and transmitting desired aggregates to conduit for upward transport. Vehicle has motor-powered water impeller, ducting and nozzle for directing pressurized sheet-jet of water rearwardly downward near undersea floor, enclosed ramp inclined rearwardly upward with entrance behind sheet-jet to receive solids dislodged from sea floor by jet, hopper and trough to receive solids moved up ramp by flow of water up ramp when vehicle is towed forward, and separating screens and ducting to direct desired sizes of solids into conduit for delivery to surface ship. Operationally effective path can be widened with horizontally fenestrated sweeps disposed in rearwardly diverging and converging V-patterns.

Abstract: Vehicle adapted for being towed along undersea floor area where desired mineral aggregates, such as manganese nodules, are dispersed on ocean bottom carries horizontally fenestrated sweeps and hydraulic transition chamber utilizing towed motion and hydraulic suction for acquiring, concentrating and transmitting desired aggregates to conduit for upward transport.

Abstract: Apparatus for separating various sizes of solid minerals, e.g., mixtures of fine sediment and larger particles or aggregates of ore, has rotating drum with internal lifters and external grousers and enables tumbling of solids in stream of water flowing through drum.

Abstract: Dual function valve for controlling flow of liquids or mixtures of liquids and solids has a movable seat for relief of excessive negative pressure and a buoyant gate for emergency discharge under excessive loads of solids.