The invention relates to a soil transport installation suitable for transporting soil and/or minerals to the water surface, whereby the soil and/or minerals have been excavated at the bottom of a body of water.

US4280288 describes a modular drain unit for collecting polymetallic nodules at the sea bed. The nodules are first collected, and the collected nodules are transported into a storage bin. This bin is subsequently used to transport the nodules to the water surface.

DE2701393 describes a system to collect minerals from the sea floor and transport the minerals to the water surface. In this system the minerals are transported by means of a conveyor belt to an upper opening of a transport container. This container is then transported to the water surface by means of cables.

US 2016/0176664 describes an installation comprising a vessel for canying out the treatment of excavated ore, a higher positioned platform that is connected to the vessel, and a lower positioned platform that rests on the bottom of the ocean. Between the higher positioned platform and the lower positioned platform containers for excavated ore can move along transport cables.

US2014219769 describes a method for transporting transport containers that are filled with a load, for example oil, along cables from a certain point on the seabed to the water surface. Because of the lower density of the oil the container will move upwardly along the cables. Air is added to separate compartments in the transport container to increase the stability thereof.

The above systems and methods are suited to transport minerals as excavated as larger particles to the water surface. The systems and methods are less suited to transport soil and/or minerals which are excavated at the sea floor as an aqueous suspension. The present invention provides a soil transport installation which is suited to transport both larger soil and/or mineral particles and soil and/or minerals which are excavated at the sea floor as an aqueous suspension to the water surface.

The present invention relates to the following soil transport installation.

Soil transport installation, comprising:

a submersible frame,

an intake for excavated soil and/or minerals,

one or more storage containers that are suitable for the storage of excavated soil and/or minerals and suitable to be transported to a water surface, comprising one or more product intake openings which are, by means of a releasable fluid connection, connected to the intake of excavated soil and/or minerals, as well as positioning means capable of positioning the storage container on the submersible frame and in which the storage container furthermore comprises an outlet for water that is depleted of excavated soil and/or minerals, and in which between the product intake and the outlet for water that is depleted of excavated soil and/or minerals a decanting zone is present..

The soil transport installation according to the invention provides a decanting zone within the storage container which results in that more soil and/or minerals may be stored in the container and less water. This increases the efficiency of for example the excavation of the sea floor because more soil can be easily collected in one storage container and transported in said container to the water surface.

The frame is submersible. This can be realised by influencing the weight of the frame itself. The frame preferably comprises compartments that can be alternatively filled with a gas, for example air, and with water. These spaces are preferably chosen in such a way that the frame can float, be submersed, and rise depending on the contents of the spaces. The fact that the frame can float is an advantage because it is thereby possible to create an easily displaceable soil transport installation. The frame can have any form possible, for example a triangle and preferably a square. A square frame consists of two framework beams that, together with two transverse beams, form a quadrilateral and preferably rectangular frame. Such a frame preferably comprises four corners. The term "corners" refers to any construction that is suitable for being connected to the framework beams and to the transverse beams. The construction is preferably also suitable for being equipped with supporting means and with anchoring means. The construction for the corners can for example be a boxlike construction or a lattice construction. Boxlike constructions are interesting because they can possibly be filled with water and gas in order to float, submerse, or raise the frame.

The frame preferably comprises means to anchor the frame to the ground. These means are preferably screw anchors or suction anchors. These means are preferably present in the corners of the submersible frame. The submersible frame preferably comprises supporting means. Such supporting means are preferably one or more wheels, caterpillar tracks, or a sled. These means are preferably present in the corners of the submersible frame. Using the supporting means, the frame can be moved along the bottom of water while the soil transport installation remains in the submersed position. This is an advantage because the soil transport installation can thus be easily displaced over a plane of the bottom of water that still needs to be excavated. For the movement it can be interesting that the soil transport installation comprises one or more means to displace the frame horizontally. Preferably, these means can be so-called thrusters or the aforementioned caterpillar tracks and/or driven wheels. The quadrilateral frame is preferably rectangular because this simplifies the construction. By fixing such a frame to the bottom of water it is simple to couple the soil transport installation with an adjacent excavation installation that also presents a rectangular form.

The framework beams and the extremities of the transverse beams of a rectangular frame are preferably resiliently connected to a corner in each of the four corners of the frame by means of a ball joint. The comers of the frame preferably comprise the aforementioned means to anchor the frame to the ground. The corners preferably comprise the aforementioned supporting means. The means to anchor the frame to the ground are preferably resiliently connected to the corners. The supporting means are preferably resiliently connected to the corners. The combination of the springs and the ball joints in the connections of the framework beams and of the transverse beams with the corners, and the resilient supporting means lead to the fact that the frame is very well capable of following a bottom of water with irregularities when the frame is transported over the bottom of water. Also during the horizontal transportation of the frame over the bottom of water the frame is in possession of six kinematic degrees of freedom, which is an advantage when absorbing the forces that are exerted onto the frame. The form stability of the frame can be increased by adding a diagonal connection beam to two diagonally opposed corners. This beam can be connected to the corner in the same way as the framework beams and the transverse beams. By making use of the described implementation, a frame is realised with the very highest form stability, which is interesting for aligning the positioning means that position the storage containers onto the frame.

The aforementioned framework beams and transverse beams comprise preferably

compartments that can be filled with gas and/or water in order to float, submerse, or raise the soil transport installation. The gas shall in most instances be air but can also be another gas, such as nitrogen or carbon dioxide.

Further to the product intake, the storage container preferably also comprises an outlet and an intake for a gas. In this way gas may be supplied to the storage container to increase its buoyancy. The gas may be supplied by the below described gas accumulator. The storage container has an outlet for water that is depleted of excavated soil and/or minerals, whereby between the product intake and the outlet for water depleted of excavated soil and/or minerals a decanting zone is foreseen. The decanting zone is defined by a substantially horizontal flow path for water and soil and/or minerals between product intake and outlet. The horizontal length of the flow path is suitably at least 5 meters and can be up to the length of the container. The optimal flow path length will depend on the decanting speed of the soil and/or minerals particles and can be easily determined by a skilled person. The outlet for water that is depleted of excavated soil and/or minerals is preferably connected to a centrifugal pump by means of a fluid connection. Alternatively the product intake opening is connected to a centrifugal pump by means of a releasable fluid connection. The storage container is further closed such that the collected soil and/or minerals stay within the storage container during transport and such that any gas added to the storage container to increase its buoyancy does not escape.

The product intake for multiple storage containers is preferably connected to the supply pipe for excavated soil and/or minerals by means of a releasable fluid connection via a carousel distributor. The carousel distributor can connect the intake for excavated soil and/or minerals, preferably sequentially, to one or more product intakes of one of the storage containers selected from the group of the multiple storage containers. This way, the storage containers can be (semi-) continuously filled with soil and/or minerals. The filled storage containers shall be transported to the water surface, whereas the emptied storage containers shall be transported back to the soil transport installation to receive a new load.

The storage container is preferably connected to a gas accumulator. The connection is such that, during use, gas can flow into the storage container and gas can flow from the container to the gas accumulator. By letting gas flow from the gas accumulator into the storage container, the present water shall be driven out from the top of the container, which increases the upwardly directed force on the container. In the reverse situation, gas can flow from the storage container into the gas accumulator, helped by a compressor. The downwardly directed force on the storage container will then increase. Water can also be added or removed via a valve and an optional pump in cases in which no compressor is present or in which the compressor is not functioning.

The gas accumulator usually is a barrel or a drum. The gas accumulator is preferably connected to the storage container and hence shall be transported with the storage container from the bottom of water to the water surface. This in itself is an advantage, for example in cases where the compressor isn't functioning. In that case, the gas accumulator can be filled in a different way at the water surface or can be replaced by another barrel or drum with pressurised gas. The gas accumulator can also be a barrel or drum that is connected to the frame, not moving to the water surface with the storage container. When such a gas accumulator no longer contains pressurised gas, it can be replaced with an accumulator with pressurised gas, whereby the accumulator is lowered to the submersible frame. The gas accumulator can also be a barrel drum with multiple compartments that are separated from one another and that contain the pressurised gas. By connecting these compartments to the storage container, for example if per manipulation one compartment is used, the gas pressure can be kept very high. If the barrel or the drum consisted of one single space, the gas pressure would decrease after a certain number of uses to below the required pressure, for example to expel water from the storage container. The barrel or the drum can simply be replaced by a new barrel or drum with pressurised gas. Filling such a barrel or drum can be carried out on the floating vessel or on the mainland where this can be done very efficiently.

Instead of a barrel or a drum, the gas accumulator can also be a gas pipe that transports pressurised gas from the water surface to the lower positioned storage container.

Therefore, the invention also relates to a storage container comprising a storage space for excavated soil and/or minerals, one or more product intake openings for excavated soil and/or minerals, an outlet as well as an intake for a gas, an outlet for water that is depleted of excavated soil and/or minerals, and in which between the product intake and the outlet for water depleted of excavated soil and/or minerals a decanting zone is foreseen, as well as positioning means suitable for positioning the storage container onto a submersible frame. The storage container is preferably connected to a gas container in the form of a barrel or a drum, connected to the storage container in such a way that, during use, gas can be led into the storage container and also from the storage container into the gas accumulator.

Therefore, the invention relates to a soil transport system comprising the soil transport installation according to the invention, and a floating vessel comprising hoisting means that are suitable for lifting and/or guiding the storage container of a soil transport installation that is submersed on the bottom of water to the floating vessel. The soil transport system preferably comprises a submersible excavation installation comprising excavation means, and an outlet for excavated soil and/or minerals, in which this outlet is connected to the intake for excavated soil and/or minerals of the soil transport installation by means of a fluid connection. Such an excavation installation preferably comprises a submersible frame as described above for the soil transport installation. The frame of the excavation installation as well as the frame of the soil transport installation are preferably rectangular, which means that the excavation installation and the soil transport installation can be positioned next to one another on the bottom of the sea. It is even more to be preferred that such an excavation installation is sandwiched between two soil transport installations according to the invention.

The soil transport installation, the soil transport system, and the storage containers shall be illustrated in the following figures. Figure 1 shows a soil transport installation according to the invention, comprising a submersible frame (2) and an intake for excavated soil and/or minerals (3). Furthermore, four storage containers (4) can be seen that are suitable for the storage of excavated soil and/or minerals. The storage container comprises one product intake opening (5) at each side of the storage container (4). The product intake opening (5) is connected to the intake opening (3) for excavated soil and/or minerals by means of a releasable fluid connection (6). The submersible frame (2) comprises in each corner of the rectangular frame a screw anchor (7) and a sled (8). Furthermore, the corners comprise thrusters (9) that permit carrying out a horizontal and vertical movement of the frame (2). The frame (2) comprises two framework beams (10) and two transverse beams (11). A carousel distributor (12), connected to a supply pipe (40) comprising valves, forms the connection between an intake opening (3) and the storage containers (4). This can be seen in further detail in figure 7. The storage containers (4) are also connected to an outlet for water that is depleted of excavated soil and/or minerals. This outlet is situated under the storage containers (4) and is therefore invisible. What are visible however, are two centrifugal pumps (14) that are connected to this outlet by means of a discharge tube (15). Moreover, two gas accumulators (16) can be seen, which are described in further detail in figures 4a and 4b. Figure 2 shows how the extremities of the framework beams (10) and the extremities of transverse beams (11) are resifiently and by means of a ball joint connected to a corner in each of the four corners (17, 18, 19, 20) of the rectangular frame (2), whereby screw anchors (7) are resiliently connected to the corners ( 17, 18, 19, 20), and whereby the sleds (8) are resiliently connected to the corners (17, 18, 19, 20) by means of springs (21), in such a way that, when the rectangular frame (2) is anchored, the frame comprises a resilient geometry with six kinematic degrees of freedom. The resilient connection of the framework beams and the transverse beams to the corners can be implemented by means of a ball joint, a connection part, and a spring. The ball joints thereby permit limited angular displacements of the framework beams (10) and of the transverse beams (11) relative to the corners (17, 18, 19, 20). The displacements of the corners (17, 18, 19, 20) in the horizontal xy-plane is made possible by compressing or extending the springs. The sleds (8) are connected to the corners by means of springs (21) and hydraulic cylinders (22). The combination of this

implementation of the way in which the framework beams and the transverse beams are connected to the corners results in the fact that the sleds are capable of carefully following the contours of the bottom of water because the sleds comprise six kinematic degrees of freedom (x, y, z, φ, θ, ψ). Thanks to the kinematic degrees of freedom (x, y, z, φ, θ, ψ) of the sleds (8) the sleds are capable of carefully following the contours of the bottom of water when horizontal movements of the frame (2) are carried out. Moreover, the moments in the corners (17, 18, 19, 20) will be strongly reduced thanks to the flexibility of the frame (2). The frame (2) can be further rigidified by using tube like beam elements (23) that form a connection by means of a ball joint and a spring between two comers (18, 20) in a diagonal direction.

Figure 3 shows a corner in further detail. In order to absorb the fluctuating loads and all the impact loads on the sleds (8) or possible wheels or caterpillar tracks, a spring (21 ) is clamped in between a plate (25) that is connected to the sled (8) and a plate (24) that is connected to a hollow vertical cylindrical column (26) and a hydraulic cylinder (22). A cylindrical guiding tube (27) that is connected to the plate (25) can move back and forth vertically at the inside of the cylindrical column (26). A hollow cylindrical tube (26) can move back and forth vertically at the inside of a tube (32) that is connected to the plates (23, 29). The plates (23, 29) are connected to comer (18). By means of hydraulic cylinders (28) that are connected to plate (29) that in turn is connected to the corner (18), the assembly of the sled (8) and the hollow vertical cylindrical tube (26) can be forced to move vertically. In order to avoid bending of the cylinder rods (30), the cylinder rods (30) are connected to and surrounded by a tube (31) comprising holes, whereby this tube is guided externally around the hydraulic cylinder (28). An additional advantage thereof is that in case of an impact or fluctuating loads on the sled extra damping is created by the in and out flowing water through the holes in tube (31 ). An interesting method of avoiding a rotation of the sled (8) around the z-axis can be put into practice by using the counter-acting rotation moment of helical spring (21) that is fixed at both ends to the plates (24, 25).

Figure 3 shows a possible embodiment of a means to anchor the frame (2). Screw anchor (7) consists of a cylindrical hollow rigid tube (33) that is connected to 2 hydraulic cylinders (35) by means of an upper plate (34). Around part of the hydraulic cylinders (35) a hollow and water permeable tube (35a) with holes is placed to add extra strength. At the bottom of tube (33) one can see a rotatably driven screw (36). The tube (33) can move freely vertically through the corner (18) and is connected to this corner (18) by means of the upper plate (34) and hydraulic cylinders (35). The tube (33) may be filled with water to prevent the buoyancy forces working on the tube and can comprise holes that permit the in and out flow of water to facilitate the vertical displacement of the tube.

Figure 4a shows how the corners (17, 18, 19, 20), the framework beams (10) and the transverse beams (1 1 ) of the submersible frame (2) and the storage containers (4) are filled with a gas and with water. Figure 4 shows by way of example corner (18). By means of an accumulator (A), comprising gas under a pressure p2 that is bigger than the surrounding pressure pi, after opening of the pressure regulating valve K5 and valve l in situation 1 (Tl), the water can be expelled from corner (18), for example by a polytropic gas expansion, and can be discharged with pressure p2 to the surroundings via valve K3, in such a way that situation 2 (T2) is reached. By filling the corners ( 17, 18, 19, 20), the framework beams (10) and the transverse beams (11) with gas an upwardly directed force is created that permits the transportation of the soil transport installation (1) to the water surface. The different compartments of these parts of the frame can be connected to the same accumulator (A) and/or can each be separately connected to an accumulator (A). Gas accumulators (16) in figure 1 are examples of a possible embodiment. To move from situation 2 (T2) to situation 1 (Tl), the gas will be expelled by means of a compressor C driven by an engine Ml. The gas will be guided to the accumulator A after the opening of valve K2 via the non-return valve K6. After the gas in the accumulator A has been stored under pressure p2, for example by means of a polytropic compression, the pressure of the remaining gas in the compartment A shall be lower than the surrounding pressure pi , and water from the surroundings can enter the compartment via valve K3. The remaining gas can be removed from the compartment through the vent valve K4.

To move from situation 2 (T2) to situation 1 (Tl) in cases in which the compressor C is not functioning, the gas can be removed from compartment A through vent valve K4 by means of a water pump (PI ) represented by the dotted line, which, after valve K7 has been opened, feeds in water under pressure pi from the surroundings. This way the full compartment can be filled with water under pressure pi.

To move from situation 1 (Tl ) to situation 2 (T2) in cases in which the accumulator (A) and/or the pressure regulating valve K5 is not functioning, the water pump (P2), represented by the dotted line, can be used to expel the water from the compartment into the surroundings and at a pressure that is higher than the surrounding pressure PI .

An alternative method for filling the compartment of corner (18) with water can be seen in figure 4b. There, use is made of the water pump PI that, after opening valve K6 under pressure p3 pumps water, whereby p3 is higher than the surrounding pressure pi . All the gas can possibly be removed from the compartment via the vent valve K4 or via the compressor C3, represented by the dotted line, via the non-return valve K5 and transported to the accumulator (A). To move from situation 1 (Tl ) to situation 2 (T2), the water can be removed from the compartment by using water pump P2 after valve K7 has been opened under a pressure p3 that is just a little bit higher than the surrounding pressure pi . In cases in which the water pump P2 is not functioning, the gas can possibly be led to the compartment from the accumulator (A) via the compressor C2 after valve Kl has been opened under a pressure p3 that is just a little bit higher than the surrounding pressure, whereby the water can possibly be discharged via the opened valve K3.

Figure 5 shows a schematic cross-section of a storage container (4) comprising one product intake opening (5) on each side of the storage container (4). The floor plan of the container is an elongated rectangle. The product intake opening (5) is connected to a supply pipe (40) for excavated soil and/or minerals by means of a releasable fluid connection (6). The storage container (4) comprises at its bottom side 4 positioning means (41) for positioning the storage container (4) onto the submersible frame (2). The positioning means 41 are connected to winches by means of winch cables, positioned on the submersible frame, as can be seen in figure 10a. At the top side, positioning means (42) are also visible that are connected by means of winch cables and winches to a floating vessel, as can be seen in figure 10. These can position the storage container onto a floating vessel in cases in which the storage container has been brought to the water surface. The outflow opening (43) of the product intake opening (5) is directed downwardly and is in possession of the geometry of a diffusor, upstream varying from a small to a large cross-section surface, and resulting in a sufficiently low settling velocity to realise an efficient decanting of the soil particles in the soil/water mixture in the storage container (4). An outlet (44) for water that is depleted of excavated soil and/or minerals is centrally located. The inflow opening (45) with the geometry of a diffusor for this outlet (44) is positioned at a distance relative to the bottom (46) of the storage container (4), in such a way that a zone is created where the excavated soil and/or minerals can settle. By letting the soil and/or the minerals settle, water is produced that is depleted of soil and/or minerals, with a contents that is lower than in the mixture that is supplied via the inlet opening. This water flow (47) can subsequently be discharged via outlet (44). To facilitate the decanting of soil and/or minerals it is preferred to maximise the path length of the water flow between the intake (5) and the outlet (44). This is done by foreseeing a horizontal plate (48) that gives rise to a flow line/curve that is sufficiently long for soil and/or minerals to settle. Figure 5a also shows an outlet opening (49) for a gas, connected to a compressor, as well as an inlet opening (50) connected to a pressure regulator valve for a gas, connected to a gas accumulator (54). The storage container is further closed to keep the soil and/or minerals and the buoyancy gas within the container.

Figure 6 shows an alternative storage container (4). The difference between this and the storage container from figure 5 is that the outlet (44) now comprises two inflow tubes. The flow of water along flow path (51) is directed by plates (52) and (53).

Figure 6a shows an alternative storage container comprising two inflow openings (40) for the inflow of the soil/water mixture and two outflow openings (44) for outflow of the water flow (47). The differences between this and the storage containers of figures 5 and 6 are that the outlet water flow (47) is guided along vertical walls (53a) forcing the water flow (47) to follow a route against the gravitational acceleration, thereby preventing soil particles not to settle in the storage container(4a).

Figure 6b shows an alternative storage container (4). The differences between this and the storage containers of figures 5, 6 and 6a are that this container comprises one inflow opening (40) for the inflow of the soil/water mixture and one outflow opening (44) for outflow of the water flow (47) thus maximizing the path length of the water flow between the intake (5) and the outlet (44) and facilitating the decanting of soil and/or minerals in the storage container (4a). In analogy with the storage container of figure 6a the outlet water flow (47) is also guided along a vertical wall (53a) forcing the water flow (47) to follow a route against the gravitational acceleration, thereby preventing soil particles not to settle in the storage container(4a).

Figure 7 shows part of a soil transport system according to the invention. Certain parts have not been drawn in for reasons of simplicity. One sees parts of a soil transport installation (1 ) from figure 1, connected to a submersible excavation installation (60) that can be seen in figure 10. Of the excavation installation (60) a row of excavation wheels (61) can be seen that are connected to the intake (3) for excavated soil and/or minerals of the soil transport installation (1) by means of multiple, vertically displaceable suction tubes (60a) in surrounding discharge suction tubes (60b) via connecting suction tubes (60c, 62). Also shown is a bifurcation (63) of the discharge suction tubes (62). This bifurcation can be connected to a second soil transport installation (not represented), as can be seen in figure 10. The row of excavation wheels (61) can preferably move horizontally in a direction, this perpendicular to the direction of the row. This way, a rectangular plane can be dredged or excavated. The soil transport installation shall remain in the same spot while this is being done. The intake (3) for excavated soil and/or minerals of the soil transport installation preferably is a flexible and in its length variable suction tube (64) that is connected to a movable outlet for excavated soil and/or minerals of the excavation installation (60). This way, the connection can be guaranteed during the movement of the excavation installation (60) relative to the soil transport installation (1). The row of excavation wheels (61) can move back and forth in a direction that is perpendicular to the row itself. The intake (3) for excavated soil and/or minerals of the soil transport installation (1 ) preferably is a flexible and in its length variable suction tube (64) that is connected to a movable outlet for excavated soil and/or minerals of the excavation installation (60). This way, the connection can be guaranteed during the movement of row (61 ). A carousel distributor (12) from figure 8 comprises the flexible suction tube (64) that is wound around a rotatable frame (65). When the excavation installation (60) moves away from the carousel distributor (12), the flexible suction tube (64) of the carousel distributor (12) will unwind and thus bridge the larger distance. See figure 8 for further details.

Figure 7 also shows how the suction tube (64) on the carousel distributor (12) is in fluid connection with the product intake openings (5) on each side of the four storage containers (4) via the supply pipes (40) for excavated soil and/or minerals. Furthermore, one sees that each storage container (4) comprises an outlet (44) for water that is depleted of excavated soil and/or minerals. These outlets are connected to at least two centrifugal pumps (14) by means of a discharge pipe (15). By pumping away water, the centrifugal pumps (14) create an under pressure in the storage containers (4). The result of this is a suction of a mixture of water excavated soil and/or minerals. This suction process continues to the fluid connected discharge suction tube (62) through which the excavated soil and/or minerals are sucked away at the excavation wheels (61). By equipping the supply pipes (40) and the discharge tube (15) with valves it is possible to couple the storage containers (4) sequentially or group wise with the excavation installation (60). This way, the excavated soil and/or minerals are distributed by means of the carousel distributor (12). Already filled storage containers can then be brought to the water surface while other storage containers are being filled.

Figure 8 shows the carousel distributor (12) in further detail. The rotatable frame (65) is at its top and bottom side equipped with bearing constructions (66) around which the frame (65) can rotate. The flexible suction tube (64) is connected upstream to the discharge suction tube (62) via the intake opening (3) for excavated soil and/or minerals. Downstream, the flexible suction tube (64) is connected to a stationary vertical tube (67) by means of a flanged joint, in turn connected to the discharge tube (40). Figure 9 shows a soil transport system according to the invention in which an excavation installation (60) is sandwiched between two soil transport installations ( 1). The excavation installation (60) comprises a similar rectangular frame to the soil transport installations (1 ). The excavation installation (60) and the two soil transport installations ( 1) are connected to a floating vessel (73) by means of cables (70). After use, the installations can be transported to the floating vessel (73). In the figure the distance in longitudinal direction between the excavation installation (60) and the soil transport installations (1 ) is represented relatively small for reasons of clarity of the drawing. One can imagine, though, that this distance in longitudinal direction can be very large, and it is not unthinkable that the distance between the floating vessel (73) and the installations (1, 60) can range from lm to 1000 m. On top of the carousel distributor (12) one sees a gas accumulator (16) that is connected to the carousel distributor (12) . In the drawing, parts of the transverse beam (11), the storage container (4), the gas accumulator (16), the corners ( 17, 18), as well as part of the excavation installation (60) are represented with fine hatch lines. The fine hatch lines indicate the presence of water, whereas for the storage containers (4) they indicate water and soil and/or minerals (not shown in the figure). The fine hatch lines indicate gas. The floating vessel preferably comprises positioning means and preferably a dynamic positioning to ensure that the vessel remains positioned above the installations (1 , 60).

The gas accumulator (16) can be connected identically to the storage container (4) as described in figures 4a and 4b. The gas accumulator (16) is not drawn to scale. By replacing the upper part of the water present in the storage container with gas the storage container becomes lighter and can simply, filled with soil and/or minerals, be pulled to the floating vessel (73) by means of winch cables (74). The vessel (73) comprises winches (75) as hoisting means to transport the storage containers (4) and the installations (1, 60) to the floating vessel (73). The vessel (73) furthermore comprises means to remove the soil and/or minerals from the storage containers. The vessel (73) itself or other vessels can be equipped with installations for storing the soil and/or minerals.

Figure 10 shows a perspective view of the soil transport system from figure 9. Please note that in this drawing not all cables (74) are represented.

Figure 10a shows the vertical transport and positioning system of the containers in further detail, whereby the numbers have the same meaning as before.

The invention also relates to a method for transporting excavated soil and/or minerals from a bottom of water to the water surface, in which the method comprises the following steps: a. transporting a storage container for soil and/or minerals, filled with water, from a floating vessel to a submersible frame that is positioned on the bottom of water, b. filling the storage container with soil and/or minerals which are fed to the storage container in the form of a mixture consisting of soil and/or minerals and water, in which the soil and/or minerals settle into the storage container, and a stream of water that is depleted of soil and/or minerals is discharged from the storage container, c. expulsing part of the water from the storage container by means of a pressurised gas, in such a way that the upwardly directed force that is exerted onto the storage container increases,

d. letting the storage container, as obtained in step (c), rise to the floating vessel, e. removing the soil and/or the minerals from the storage container to a storage space that is present on the floating vessel or on another floating vessel, and f. filling the storage container with water, in such a way that the downwardly

directed force that is exerted onto the storage container increases, such that step (a) can be carried out.

The gas in step (c) is preferably compressed air that is stored in an accumulator that is connected to the storage container. This gas can also be nitrogen or carbon dioxide. The accumulator can be filled in step (f) with compressed gas. It is preferred that the compressed gas with which the accumulator in step (f) is filled, is the gas that in step (c) is led to the storage container. Preferably, the storage container is in step (a) and (d) submersed or lifted by means of cables and winches.

Preferably, the soil transport installation according to the invention is used in this method. Figures 11 and 12 show the method described above, in which the cycle is represented of the different periodical phases of the process during the filling procedures of soil in the global compartments (4a) of the soil storage containers (4) and the vertical soil transport.

Process phase 1: both compartments (4a and 4b) of the storage container are filled with water under surrounding pressure PO. The water in the upper compartment (4b) has a volume (VI- V2). The accumulator (54) that is coupled to the storage container has a pressure P2 and volume V2. None of the filling systems, including the compressor drive, are functioning.

Process phase 2: the lowering of the storage container (4), inclusive of the accumulator (54) (not represented in figure 1 1 ), takes place at a constant speed V by virtue of a vertical force equilibrium made up of both the weight (under water) of the container Fg, and the upwardly directed force of the accumulator Fo and the resistance of the water Fw, or: Fg = Fo + Fw.

^* Total upwardly directed force Fo = Fv2

^* upwardly directed force by accumulator Fv2 = (p-w)*V2*g

^* density of water p-w

^* volume of the accumulator V2

' gravitational acceleration c o

^* water resistance storage container Fw = = Cd* l/2*(p-w)*V ²

^* lowering speed storage container V

^* total weight force (under water) Fg = Fc-ow

^* weight underwater of complete container Fc-ow

The underwater weight of the complete container refers to the total weight underwater of the container, the accumulator, and installations. A certain part of the upper gas compartment (4b) of the soil storage container can possibly be used to compensate the underwater weight of the soil storage container.

Process phase 3: once the container is part of the storage container installation on the bottom of water the water is expelled from the upper compartment (4b) against the surrounding pressure PI through the opened valve K5, by adding air from the accumulator (54) following an expansion via the opened valve Kl , the pressure regulating valve K6 that is opened if the pressure is higher than PI , and the volumetric flow rate control valve K7 (adjusted to a volumetric flow Qv-gl). The volumetric flow Qv-gl equals the added soil in the lower compartment (4a) in the sense that the upwardly directed force of the gas in the upper compartment (4b) is equal to the underwater weight of the soil in the lower compartment (4a).

Process phase 4: continuation of the flow Qv-gl from the accumulator (54) following expansion via a valve Kl , pressure regulating valve K6, and volumetric flow rate control valve K7 to the upper compartment (4b), leading to an increase in volume "v" of gas in the upper compartment (4b) (see process phase 4). Continuation of the flow takes place until in process phase 5 the total quantity of water is expelled from the upper compartment (4b) against the surrounding pressure PI , and the gas in the compartment with volume (VI -V2) has a pressure PI . Proportionally, the amount of soil in the lower compartment (4a) has increased to a value that, during the rising (process phase 6), a force equilibrium is formed between the total upwardly directed force Fo and the total downwardly directed weight force Fg and the water resistance force Fw.

The total energy E-e (inclusive of energy losses) that is released by the expansion of a gas under pressure P2 to a pressure PI has to be at least equal to the necessary work A (inclusive of energy losses) that is necessary to expel the water from the upper compartment (4b) with volume VI -V2 against the surrounding pressure PI.

Process phase 6: the rising of the storage container (4), including the accumulator (54) (not represented in figure 11 ), takes place at a constant speed V under a vertical force equilibrium that is made up of the total upwardly directed force Fo that is equal to the sum of the total weight force (underwater) of the complete container and soil (Fg) and the water resistance Fw, or Fo = Fg + Fw. * Total upwardly directed force Fo = Fvl

^* upwardly directed force by accumulator

and compartment Fvl = (p-w)*Vl*g

^* volume (accumulator + compartment) VI

^* gravitational acceleration g

* water resistance storage container Fw = Cd* l/2*(p-w)*V ² *A

^* projected surface area of the storage

container (perpendicular to the velocity V) A

^* rising speed storage container V

^* total weight force (under water) Fg = Fc-ow + Fs_ow

* weight underwater of complete container Fc-ow

^* weight underwater of soil Fs_ow = (p-s-(p-w))*Vg*g ^* soil volume

^* density soil

^* density water Process phase 7: emptying or removing soil from the containers into floating barges. Once the container reaches the water surface, the soil is removed from the container (4) and is for example transferred to floating autonomously in navigating barges (57), for example by opening bottom valves (4c) that are part of the container, for example and under the influence of hydraulic cylinders. Another possibility for the horizontal soil transport is to transport the soil/water mixture via a floating pipeline, and to dump it at the end of the pipeline.

Process phase 7-8: filling the accumulator with the aid of a compressor with air to a pressure P2. Filling the accumulator (54) with air to a pressure P2 via the opened valve K2 takes place with the aid of a compressor C, driven by an engine Ml. The volumetric flow rate of the gas is stored in the accumulator (54) with volume V2 and final pressure P2, via the non-return valve K8 from the upper compartment (4b) with initial volume V1-V2 and initial pressure PI by means of a compression. During the filling of the accumulator (54) the pressure in the upper compartment (4b) of the soil storage container eventually decreases to P0 (phase 8), whereas the pressure in the accumulator (54) eventually increases to P2. The non-return valve K8 will only open if the pressure from the compressor side C becomes larger than or equal to the pressure P2 ^' in the accumulator (54), whereby PI < P2'< P2. The compressor C fills the accumulator (54) to a final pressure P2 with air from the upper compartment (4b) and/or with surrounding air. After the accumulator (54) with volume V2 has been filled to a final pressure P2 the air pressure in the upper compartment (4b) must have decreased to the surrounding pressure P0.

Process phase 1: after opening valve K3, the water pump P that is driven by engine M2 expels the gas from the higher compartment (4b) in pumping water to the compartment (4b) at a pressure that is slightly above the surrounding pressure PO via the opened vent valve K4. Subsequently, the periodic cycle starts all over again. Figure 12 shows an alternative for the high gas pressure accumulator, in which the high gas pressure accumulator (16) is composed of multiple compartments, each with a volume V2 and a pressure P2. Compartment (4b) is now connected to one of these compartments (1 ). The periodic cycle of the containers in figure 12 is almost identical to that which was described for figure 11. The difference is that the container (4) no longer comprises an accumulator (54) connected thereto. This high gas pressure accumulator (16) is lowered separately to a position in which the gas that is present in the different compartments can be used for different cycles and storage containers. All the compaitments of the high pressure gas accumulator (16) are preferably filled with a gas with volume V2 and pressure P2. To ensure the necessary lowering weight, the buoyancy forces of the compartments (16) are balanced with the weight of the accumulator and the weight of the compartments (16a) being filled with water. When raising the accumulator (16), the same compartments can be filled with a gas. Preferably the gravity forces on the gas accumulator is slightly higher than its buoyancy resulting in easy lowering and lifting to and from the sea bed, also referred to as ground or bottom of the sea in this description.