A dragged or self-propelled unit has drag shoes or other means to dislodge nodules from the sea bed into a duct which may be associated with nozzles to project fluid against the nodules. The duct increases substantially in cross-section, thereby slowing the velocity of a stream formed by the nodules, accompanying silt and water. The slowed nodules and silt are caused to follow divergent separate paths within the unit, the nodule path being relatively below the silt path, and the nodules are removed from the duct upstream of the final outlet by which silt and water depart the unit.

An apparatus for recovering minerals from the bottom of the water comprising a frame which supports a pump taking in the water and feeding it to nozzles mentioned below, a driving device for the pump, a collection chamber and at least one mineral floating apparatus, which fixed an end of a suction pipe leading to the collection chamber and which is so formed that it can travel on the bottom of the water. The above-mentioned mineral floating apparatus is integrally formed with a cylindrical surface, the nozzle arranged in contact with the cylindrical surface and jetting the water in the direction of a tangent which is at a right angle to the center axis of the cylindrical surface, a plurality of ribs projecting in the opposite direction to the side of the cylindrical surface of the nozzle and extending in the jet direction of the nozzle, and a duct which has an opening at one end of the duct at the downstream of the water jetted from the nozzle and extends slopewise in tangent with a part of the cylindrical surface so as to receive the water moved along the outside of the cylindrical surface. The above-mentioned mineral floating apparatus is so arranged that the side of the cylindrical surface having the nozzle and ribs exposes to the bottom surface of the frame, the jet direction of the nozzle and the direction of the base line of the cylindrical surface go almost parallel to the bottom surface of the frame, and the mineral floating apparatus is supported at the opposite side to the duct by a supporting shaft provided in the frame so as to be able to move the side of the duct up and down by turning the mineral floating apparatus around the supporting shaft and to swingably insert the other end of the duct into the collection chamber, whereby the above-mentioned apparatus has a simple structure, operates practically without trouble and can recover minerals from the bottom of the water.

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. Chamber can be mounted as a tail pipe suspended from framework of vehicle having runners for sliding along undersea floor with forward entrance held near floorline.

Nodule dredge comprising one or more of the following: convergent wall device, e.g., "horn member", for accelerating liquid flow through the apparatus; comb or grid-like collecting or lifting device that can lift nodules into accelerated flow without necessarily lifting an entire layer of silt, especially where silt is relatively loose; inclined surface to receive and raise nodules driven down stream by accelerated flow, while silt is removed; and collection chamber below nodule path defined by inclined surface, to receive nodules from inclined surface. Process comprising one or more of the following: accelerating a flow of water with a convergent wall device; mechanically lifting nodules into the accelerated flow; driving the nodules up an inclined surface and cleaning them, using the accelerated flow, while establishing the flow in a direction which will project water and dispersed silt upwardly and rearwardly downstream of the inclined surface; and introducing the nodules into a collection chamber having an entrance turned away from said direction of flow.

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.