Excavator and resource recovery system

Abstract

To provide an excavator capable of reducing transportation costs.SOLUTION: The present invention relates to an excavator for excavating a rare earth mud layer containing rare earths or a resource layer containing minerals, which is located under a seabed mud layer, and includes a pair of excavation rigs that are lowered to the seabed, and a main body that is located above the excavation rigs at a predetermined distance and connected to the excavation rigs via a suction pipe and a discharge pipe. The suction pipes are formed so that the internal volume of the suction pipes can reduce the pressure of the rare earth mud or resource sucked in by the suction rigs.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a technique for mining marine resources, and more particularly to a technique for mining marine resources suitable for mining resources such as rare earths or minerals from deep-sea mud. [Background technology]

[0002] In recent years, as marine resources, attention has been focused not only on resources such as minerals, but also on deep-sea mud containing extremely high concentrations of rare earths. The recovery technology for such mud involves digging up rare-earth mud using a drilling device lowered to the deep sea, then hoisting the excavated rare-earth mud to the surface and subjecting it to a solid-liquid separation process in a centrifuge on board the ship to separate solids containing rare earths. Rare earths are then recovered by a conventionally known method such as a leaching process in which rare earths are dissolved in water or an aqueous solution. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Makoto Kobayashi et al., "Special Issue Takarajima 2530: Great Discovery! The 300 Trillion Yen Business of Minamitorishima's Huge Resources," Takarajimasha, 2017 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above recovery technologies have the problem of high transportation costs, as they require marine resources such as mud containing rare earths to be transported from the deep sea to the surface.

[0005] In view of the above problems, an object of the present invention is to provide an excavator and a resource recovery system that can reduce transportation costs. [Means for solving the problem]

[0006] (1) The present invention relates to an excavator comprising a main body that is lowered to the seabed and a pair of excavation devices provided on both ends of the main body, for excavating a rare earth mud layer containing rare earths or a resource layer containing minerals below a seabed mud layer, the excavation device comprising a cylinder having an upper part rotatably arranged on the main body and a lower peripheral end face formed as a drilling blade for excavating the rare earth mud layer or the resource layer and protruding downward from the lower part of the main body, a spiral fin formed on the outer circumferential surface of the cylinder and for penetrating the cylinder into the seabed mud layer as the cylinder rotates, a cutter head rotatably arranged within the lower part of the cylinder, and a cutter head provided inside the cylinder and for rotating the cylinder and the cutter head to extract the rare earths. The excavation device has a rotary drive unit for excavating a mud layer, and a pumping device provided inside the cylindrical body for pumping rare earth mud or resources obtained by excavating the rare earth mud layer or the resource layer into the main body, and has a suction device inside the main body or inside the excavation device for sucking the rare earth mud or resources pumped by the pumping device into the main body, and is characterized in that the main body is equipped with a separation device for separating granules containing the rare earth or the mineral from the rare earth mud or resources sucked into the main body, a leaching treatment device for leaching the granules separated by the separation device, and a residue storage facility for storing the residue of the granules separated by the separation device.

[0007] (2) In the excavator of (1) above, it is preferable that the main body is formed into a cylindrical shape having an axis extending horizontally by alternately stacking multiple reinforced composite layers having a reinforced composite material containing carbon fiber and multiple steel layers having steel.

[0008] (3) In the excavator of (2) above, it is preferable that the reinforced composite layer contains a pipe therein, the pipe is filled with high-pressure gas or high-pressure liquid, and the pipe is arranged parallel to the axial direction on the circumferential surface of the main body and folded back at both ends, thereby covering the entire circumferential surface of the main body with a single pipe.

[0009] (4) The excavator of the present invention comprises a main body that is lowered to the seabed and a pair of excavation devices attached to the main body, and excavates a rare earth mud layer containing rare earths or a resource layer containing minerals located below a seabed mud layer, wherein the excavation devices have a cylindrical body protruding downward from the lower part of the main body and a cutter head rotatably arranged within the lower part of the cylindrical body, and the inside of the main body is provided with a suction device that sucks up the rare earth mud or resources obtained by excavating the rare earth mud layer or the resource layer with the cutter head, a separation device that separates granules containing the rare earths or the minerals from the rare earth mud or the resources sucked up by the suction device, a transport device that transports the granules separated by the separation device to the sea, a residue storage tank that stores the residue from which the granules are separated by the separation device, and a cement storage tank that stores cement discharged from inside the lower part of the cylindrical body.

[0010] (5) In the excavator of (4) above, the main body is formed in a cylindrical shape having an axis extending horizontally, and the main body further includes three hollow spherical bodies lined up in the axial direction of the main body, the suction device, the separation device, and the cement storage tank being arranged inside a first spherical body that is in the middle of the three spherical bodies, the separation device being arranged inside a second spherical body that is located closer to the center of the axial direction of the main body than the first spherical body, and it is preferable that a third spherical body that is located farther from the center of the axial direction of the main body than the first spherical body is the residue storage tank.

[0011] (6) In another aspect, the excavator of the present invention comprises a pair of excavation devices that are lowered to the seabed, and a main body that is disposed in the sea above the excavation devices at a predetermined distance and connected to the excavation devices via a suction pipe and a discharge pipe, and excavates a rare earth mud layer containing rare earths or a resource layer containing minerals that is located below a seabed mud layer, the excavation devices having a cylindrical body and a cutter head rotatably disposed within a lower part of the cylindrical body, the internal space of the cutter head is provided with an on-off valve provided at the tip of the suction pipe and the discharge pipe, and the main body has a suction device that sucks in the rare earth mud or resources obtained by excavating the rare earth mud layer or the resource layer with the cutter head via the suction pipe, a separation device that separates granules containing the rare earth or the mineral from the rare earth mud or the resource sucked in by the suction device, a transport device that transports the granules separated by the separation device to the sea, a residue storage tank that stores the residue from which the granules are separated by the separation device, and a cement storage tank that stores cement discharged from the lower part of the cylindrical body via the discharge pipe. The suction pipe is also characterized in that its internal volume is formed so as to be capable of reducing the pressure of the rare earth mud or the resource sucked by the suction device.

[0012] (7) The resource recovery system of the present invention comprises an excavator according to any one of (1) to (6) above, an offshore rig installed on the ocean, an eluate recovery building provided on the offshore rig, and a subsea pipeline connecting the main body of the excavator and the offshore rig, and is characterized in that leachate treated in the leaching treatment device of the main body is recovered via the subsea pipeline to the eluate recovery building of the offshore rig.

[0013] (8) A submersible vehicle of the present invention comprises a main body and a propulsion mechanism provided on the outer circumferential surface of the main body for propelling the main body, the main body being formed into a cylindrical shape having an axis extending in the horizontal direction by alternately stacking multiple reinforced composite layers having a reinforced composite material containing carbon fiber and multiple steel layers having steel. The submersible vehicle of the present invention includes the main body of the excavator, submarine, submersible boat, etc. of (1) to (6) above.

[0014] (9) In the submersible vehicle of (8) above, the inside of the main body is provided with a tank capable of storing high-pressure gas or high-pressure liquid, and a pump connected to the tank, the carbon fiber is formed into a pipe shape and arranged parallel to the axial direction on the circumferential surface of the main body and folded back at both ends so that the entire circumferential surface of the main body is covered by the single pipe, and it is preferable that the high-pressure gas or high-pressure liquid is circulated inside the pipe by the pump. Effect of the Invention

[0015] According to the present invention, it is possible to reduce transportation costs compared to the conventional method of transporting rare earth mud containing rare earths from the seabed to the sea surface. [Brief description of the drawings]

[0016] [Figure 1] 1 is a conceptual diagram showing a resource recovery system according to a first embodiment of the present invention. [Diagram 2] 1 is a conceptual diagram showing an internal structure of an excavator according to a first embodiment of the present invention. [Diagram 3] FIG. 3 is a front view of the excavator of FIG. 2. [Figure 4] FIG. 3 is an enlarged cross-sectional view of a portion of the excavator body of FIG. 2. [Diagram 5] 1 is a schematic cross-sectional view of a main body of a submarine according to a first embodiment of the present invention. [Figure 6] 1 is a schematic cross-sectional view showing an example of the vicinity of a sealing mechanism of an excavator body according to a first embodiment of the present invention. [Figure 7]FIG. 5 is a conceptual diagram showing a part of a resource recovery system according to a second embodiment of the present invention. [Figure 8] FIG. 6 is a conceptual diagram showing a part of the internal structure of an excavator according to a second embodiment of the present invention. [Figure 9] 9 is a conceptual diagram showing a portion surrounded by a dashed line indicated by A in FIG. 8. [Figure 10] FIG. 11 is a conceptual diagram showing a part of the internal structure of an excavator according to a modified example of the second embodiment of the present invention. [Figure 11] FIG. 11 is a conceptual diagram showing a part of the internal structure of an excavator according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The excavator and resource recovery system according to the present invention will be described below with reference to the drawings. Although the recovery of rare earths will be described as an example here, the excavator and resource recovery system according to the present invention can be used not only to recover rare earths, but also to excavate resource layers containing minerals and to recover marine resources such as minerals.

[0018] (First embodiment) As shown in Fig. 1, the resource recovery system 1 includes an excavator 2 lowered to the seabed, an offshore rig 3 installed at a predetermined position on the sea, an eluate recovery building 4 and a gas turbine power plant 5 installed on the offshore rig 3, and a subsea pipeline 6 connecting the excavator 2 and the offshore rig 3. In this embodiment, eight excavators 2 are arranged side by side in an adjustment building 7. The adjustment building 7 is a place where some of the extra-long power transmission lines are stored so that the power transmission lines can be extended in response to the movement of the eight excavators 2 when they move away from directly below the offshore rig 3 to a different excavation site.

[0019] As shown in FIG. 2, the excavator 2 is an excavator that excavates a rare earth mud layer containing rare earths located below a seabed mud layer, and is equipped with a main body 20 lowered to the seabed and a pair of excavation devices 21, 22 provided on both ends of the main body 20.

[0020] Since the excavation devices 21, 22 are configured as a pair and do not need to be specifically distinguished, it is noted in advance that in the following description, only one of the excavation devices 21 will be described for simplicity. The upper portion of the excavation devices 21, 22, into which the mud suction / discharge pipe 23 protruding from the main body 20 is inserted, is sealed even when the cylindrical body 21A (outer cylinder) and cutter head 21C (inner cylinder) described below are rotating, so that no liquid or the like can enter. The mud suction / discharge pipe 23 is fixed to the main body 20 and is provided so as to protrude from the main body 20 toward the excavation devices 21, 22.

[0021] As shown in FIGS. 2 and 3, the drilling device 21 has a cylindrical body 21A, a spiral fin 21B, a cutter head 21C, a rotation drive unit 21D, a pressure-feeding device 21E, and an axial pipe 21F.

[0022] The cylindrical body 21A has an upper portion rotatably arranged within the main body 20, and a lower peripheral end surface formed into a digging blade for digging the rare earth mud layer and protruding downward from the lower portion of the main body 20.

[0023] The spiral fins 21B are formed on the outer peripheral surface of the cylindrical body 21A and are configured so that the cylindrical body 21A penetrates into the seabed mud layer as the cylindrical body 21A rotates.

[0024] The cutter head 21C is configured to be rotatably arranged inside the lower part of the cylinder 21A. The cutter head 21C is arranged at a position higher than the lower end position of the cylinder 21A by a predetermined distance. At the upper part of the cutter head 21C (inner cylinder), the gap between the cylinder 21A (outer cylinder) and the cutter head 21C (inner cylinder) is sealed by a seal member. In addition, a pressure adjustment device (not shown) capable of adjusting the internal pressure of the cylinder 21A to be the same as the external pressure of the cylinder 21A is connected to the inside of the cylinder 21A via a pipe from the sea. This prevents liquids from entering the inside of the cylinder 21A (outer cylinder) even when the cylinder 21A (outer cylinder) and the cutter head 21C (inner cylinder) are rotating. In addition, the cutter head 21C does not necessarily have to be provided at the lower end of the inner cylinder. For example, the cutter head 21C may be provided at the lower end of the cylindrical body 21A (outer cylinder) and configured to rotate in conjunction with the rotation of the cylindrical body 21A.

[0025] The rotation drive unit 21D is composed of, for example, a hydraulically driven hydraulic unit (e.g., a hydraulic motor, etc.) and a transformer as its power source, and is provided inside the cylinder 21A, and is configured to rotate the cylinder 21A and the cutter head 21C to excavate the seabed mud layer and the rare earth mud layer, although not shown. The cylinder 21A (outer cylinder) and the cutter head 21C (inner cylinder) are rotationally driven by the hydraulic unit. It is preferable that the cylinders 21A and 22A of the pair of excavation devices 21 and 22 are rotated in opposite directions by the hydraulic unit. The cylinders 21A and 22A can be operated based on a predetermined program in a control unit (not shown), or can be operated by the operation of an operator. In addition, the operation data of the operator may be learned by an artificial intelligence (AI), and the cylinders 21A and 22A may be operated based on the operation data of the operator during excavation by the excavator 2.

[0026] The pumping device 21E is configured, for example, by a pressurized air lift pump or the like, and is provided inside the cylindrical body 21A and configured to pump into the main body 20 the rare earth mud obtained by excavating the rare earth mud layer.

[0027] The axial pipe 21F is disposed within the cylindrical body 21A and aligned with its axis. The cylindrical body 21A and the cutter head 21C are rotatably attached to the axial pipe 21F. The rare earth mud obtained by excavating the rare earth mud layer by rotating the cutter head 21C is pumped into the main body 20 by the pumping device 21E through the suction / discharge pipe 23 in the axial pipe 21F.

[0028] 2, a suction device (vacuum device) 20A, a separation device 20B, a leaching treatment device 20C, a residue storage 20D, a reverse conveyance device 20E, and a screw 20F are provided inside the main body 20. In this embodiment, the suction device 20A is provided inside the main body 20, but it may be provided inside the excavation device 21. The same applies to the excavation device 22.

[0029] The suction device 20A is configured to suck into the main body 20 the rare earth mud pumped by the pumping device 21E.

[0030] The separation device 20B is configured to separate granules containing rare earths from the rare earth mud that has been sucked into the main body 20. In this embodiment, the mud is separated into granules and muddy water by a centrifugal separation process using a centrifuge.

[0031] The leaching treatment device 20C is configured to perform a leaching treatment on the granules separated by the separation device 20B. In the leaching treatment, a leaching liquid is used to treat solid components containing rare earths. For example, dilute hydrochloric acid is used as the leaching liquid. The leaching eluate treated in the leaching treatment device 20C is collected in the eluate collection building 4 of the offshore rig 3 via the subsea pipeline 6.

[0032] The residue storage 20D is configured to store the residue from which the granular matter has been separated by the separation device 20B. The residue storage 20D stores the muddy water separated by the separation device 20B for reuse as backfill material.

[0033] The reverse conveying device 20E is composed of, for example, a pressurized air lift pump, and is configured to reversely convey the residue stored in the residue storage 20D into the axial pipe 21F. After the cutter head 21C finishes excavating the rare earth mud layer, the suction device 20A of the main body 20 and the pumping device 21E of the excavation device 21 are driven in reverse, so that the residue (mud water) reversely conveyed into the axial pipe 21F by the reverse conveying device 20E is backfilled into the recess formed by the excavation.

[0034] A plurality of screws 20F are provided at predetermined intervals on the outer peripheral surface of the main body 20. The operation of the plurality of screws 20F enables the excavator 2 to move to a predetermined excavation location. The screw 20F can be operated based on a predetermined program in a control unit (not shown), or can be operated by an operator. Alternatively, the screw 20F may be operated so as to suppress the influence of the submarine current during excavation by the excavator 2 by measuring the submarine current with a measuring device (not shown) and having an artificial intelligence (AI) learn the measured data.

[0035] The main body 20 is formed into a cylindrical shape having an axis extending in the horizontal direction by alternately stacking a plurality of reinforced composite layers made of a reinforced composite material containing carbon fiber and steel layers made of steel. One example of a reinforced composite material containing carbon fiber is CFRP (Carbon Fiber Reinforced Plastic) in which carbon fiber is mixed into a thermosetting resin such as epoxy resin or phenolic resin. The CFRP according to this embodiment is preferably improved so as to have a compressive strength in the thickness direction that can withstand the high pressure environment of the seabed (for example, at a depth of 6000 m). As a result, by using the reinforced composite material containing carbon fiber instead of steel, it is not necessary to make the steel thick, and the amount of steel can be reduced.

[0036] Here, as an example of the main body 20, as shown in FIG. 4, a cylindrical container body having a four-layer structure in which steel layers L2, L4 and reinforced composite layers L1, L3 having carbon fibers laminated on the steel layers L2, L4 are alternately laminated, and the axis of the container body extends in the left-right direction. The carbon fibers of the outermost reinforced composite layer L1 are arranged parallel to the axis direction from one end of the container body to the other end, folded back at the other end and arranged adjacent to the first line toward one end, and folded back at the one end, and these arrangements are repeated, so that the entire peripheral surface is covered with a single carbon fiber without any gaps. The carbon fibers are formed into a pipe shape, and the pipe is filled with high-pressure gas or high-pressure liquid. The thickness of the reinforced composite layer L1 is set to, for example, 5 cm. The thickness of the steel layer L2 is set to, for example, 100 cm. The thickness of the reinforced composite layer L3 is set to, for example, 5 cm. Moreover, the thickness of the steel layer L4 is set to, for example, 70 cm.

[0037] 4, the reinforced composite layer L1 is formed of a sheet-like CFRP containing a pipe (tube) 24 therein, and the pipe may be filled with a high-pressure gas or a high-pressure liquid. The pipe (tube) 24 may be arranged parallel to the axial direction on the circumferential surface of the main body 20 and folded back at both ends (formed in a zigzag pattern), so that the entire circumferential surface is covered with a single pipe. In other words, the piping of the pipes can be all connected and laid in a single line over the entire surface of the main body 20.

[0038] This ensures a repulsive force against water pressure, weakens the pressure applied to the inside of the main body 20, and ensures a structure that can withstand water pressure. Specifically, at the bottom of the sea (for example, 500 atmospheres (about 50 MPa) to 1000 atmospheres (about 100 MPa)), the pressure difference with the atmospheric pressure becomes large, so that the area inside the main body 20 where the centrifugal separation process and the leaching process are performed must be maintained at atmospheric pressure. Therefore, it is necessary to ensure pressure resistance on the outside of the main body 20. For this reason, beams that increase strength may be provided appropriately in the internal space of the main body 20. Also, beams that increase strength may be provided appropriately in the internal spaces of the cylinder 21A (outer cylinder) and the cutter head 21C (inner cylinder) so as not to come into contact with the mud suction / discharge pipe 23 and the axial pipes 21F and 22F.

[0039] In this embodiment, of the reinforced composite layers L1 and L3 having carbon fibers, only the outermost reinforced composite layer L1 includes a carbon fiber member (pipe 24) formed into a pipe shape, and the reinforced composite layer L3 sandwiched between the steel sheets is formed, for example, only from CFRP. Of course, the reinforced composite layer L3 may also include a carbon fiber member (a pipe similar to the pipe 24) formed into a pipe shape.

[0040] In this embodiment, the outermost reinforced composite layer L1 is formed of, for example, CFRP including the pipe 24 inside, but the present invention is not limited to this, and the reinforced composite layer L1 may be formed of only one of CFRP and the pipe 24. That is, the reinforced composite layer L1 may be formed of, for example, only CFRP, or may be formed of only a pipe-shaped material. In the case of only a pipe-shaped material, the carbon fibers may be arranged on the circumferential surface of the main body 20 in parallel with the axial direction and folded back at both ends (formed in a zigzag pattern), so that the entire circumferential surface is covered with a single pipe. That is, all the piping of the pipe can be connected, and the pipe can be laid in a single line over the entire surface of the main body 20.

[0041] As described above, according to the excavator and resource recovery system of this embodiment, the rare earth is dissolved in water or an aqueous solution or the like by leaching treatment inside the main body 20 lowered to the seabed, so that rare earth can be efficiently recovered with high purity. Therefore, the transportation cost can be reduced compared to the conventional method of transporting rare earth mud containing rare earths directly from the seabed to the sea.

[0042] Although the excavator and resource recovery system of the present invention have been described based on the drawings, the specific configuration should not be considered to be limited to these embodiments. The scope of the present invention is indicated by the claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims.

[0043] In the above embodiment, the pipe made of carbon fiber is filled with high-pressure gas or high-pressure liquid from the offshore rig 3, but this is not limiting, and a device for filling the pipe with high-pressure gas or high-pressure liquid may be housed inside the main body 20 (the internal space in which the separation device 20B and the leaching treatment device 20C are housed). This makes it possible to apply the present technology to a submarine that moves underwater (for example, a submarine 100 as shown in FIG. 5). Below, the submarine 100 will be specifically described with reference to FIG. 5.

[0044] As shown in FIG. 5, the submarine 100 has a main body 30 and a screw 35 as a propulsion mechanism for propelling the main body 30. A plurality of screws 35 are provided at predetermined intervals on the outer circumferential surface of the main body 30. The main body 30 is provided therein with a first tank 36 and a second tank 37 capable of containing high-pressure gas or high-pressure liquid at 1000 atmospheres, and a pump 38 connected to the second tank 37. The first tank 36 and the second tank 37 are connected via an adjustment valve 39, and the first tank 36 is filled with high-pressure gas or high-pressure liquid before diving. The following describes a case where the first tank 36 is filled with high-pressure air at 1000 atmospheres as an example of high-pressure gas before diving.

[0045] The main body 30 of the submarine 100 is formed into a cylindrical shape having an axis extending in the horizontal direction by alternately stacking a plurality of reinforced composite layers made of a reinforced composite material having carbon fiber and steel layers made of steel. Specifically, as shown in FIG. 5, the main body 30 is cylindrical having a four-layer structure in which steel layers L32, L34 and reinforced composite layers L31, L33 having carbon fiber stacked on the steel layers L32, L34 are alternately stacked. The thickness of the reinforced composite layer L31 is set to, for example, 13 cm. The thickness of the steel layer L32 is set to, for example, 100 cm. The thickness of the reinforced composite layer L33 is set to, for example, 5 cm. The thickness of the steel layer L34 is set to, for example, 70 cm.

[0046] An example of a reinforced composite material containing carbon fibers is CFRP. The CFRP used in the main body 30 of the submarine 100 is preferably one that has been improved so as to have compressive strength in the thickness direction sufficient to withstand the high-pressure environment of the ocean bottom (e.g., at a depth of 6000 m).

[0047] The pipe 41 included in the outermost reinforced composite layer L31 is arranged in parallel to the axial direction from one end to the other end of the main body 30, and is folded back at the other end and arranged adjacent to the first line toward one end, and is also folded back at the one end, and these arrangements are repeated, as in the above embodiment. In other words, the entire peripheral surface of the main body 30 is covered with a single pipe without any gaps. The pipe 41 of the reinforced composite layer L31 has one end connected to the pump 38 via a pipe 40a, and the other end connected to the first tank 36 via a pipe 40b.

[0048] In the submarine 100 having the above configuration, the operation of the pump 38 and the opening of the regulating valve 39 are controlled by a control unit (not shown) to supply a predetermined amount of high-pressure air from the first tank 36 to the second tank 37. Next, a predetermined amount of high-pressure air from the second tank 37 is supplied from the pump 38 to one end of the pipe of the reinforced composite layer L31 via the pipe line 40a. The high-pressure air supplied to one end of the pipe passes through the pipe covering the entire circumferential surface of the main body 30, returns to the first tank 36 from the other end of the pipe via the pipe line 40b, and is supplied to one end of the pipe again via the second tank 37. Therefore, the high-pressure air can be circulated by the pump 38 inside the pipe of the reinforced composite layer L31, which is the outermost part of the main body 30, and a repulsive force capable of countering the water pressure is secured, thereby weakening the pressure applied to the inside of the main body 30. In addition, the high-pressure air from the first tank 36 passes through the second tank 37, thereby reducing the load on the pump 38 during operation.

[0049] In the submarine 100, the reinforced composite layer L31 located on the outermost side of the main body 30 is formed of, for example, CFRP containing the pipe 41 therein, but this is not limiting, and the reinforced composite layer L31 may be formed of only one of CFRP and the pipe 41. In other words, the reinforced composite layer L31 may be formed of, for example, only CFRP, or may be formed of only a pipe-shaped component.

[0050] In the submarine 100, of the carbon fiber reinforced composite layers L31, L33 of the main body 30, only the outermost reinforced composite layer L31 includes a pipe 41 formed in a pipe shape, and the reinforced composite layer L33 sandwiched between the steel layers is formed only of, for example, CFRP, but is not limited to this. For example, the reinforced composite layer L33 may also include a pipe similar to the pipe 41.

[0051] Furthermore, in the submarine 100, the second tank 37 does not necessarily have to be provided inside the main body 30. For example, the pump 38 may be configured to be directly connected to the first tank 36.

[0052] In the above embodiment, the area around the upper portion of the excavation equipment 21, 22 where the mud suction / discharge pipe 23 extending from the main body 20 is inserted is sealed even when the cylinder 21A (outer cylinder) and cutter head 21C (inner cylinder) described below are rotated, and a sealing mechanism is provided to prevent liquids from entering. A specific example of this sealing mechanism will be described. Note that reference numerals with the same last two digits as the above embodiment represent the same parts, and therefore their explanation may be omitted. In this specific example, parts not specifically described or not shown are the same as the parts in the above embodiment.

[0053] As shown in FIG. 6, the sealing mechanism 150 includes a cover portion 151 having a substantially T-shaped cross section, sealing members 152, 153, 154, and 155, an inner cover 160, a dome-shaped portion 170, and an axial pipe 121F.

[0054] The lid 151 is made of steel and has a shaft 151a, a head 151b provided on the top of the shaft 151a, and a hole 151c that passes through the center. The hole 151c has an internal thread, and a male thread 162 at the top of the inner lid 160 (described later) is screwed into the hole 151c, fixing the lid 151 and the inner lid 160 together. After the male thread 162 is screwed into the hole 151c, the top is fixed and sealed with an adhesive or the like. The outside of the shaft 151a is fixed to a hole 121A1 at the top of the cylinder 121A.

[0055] The inner lid 160 is made of steel and includes a base 161 that fits tightly against the inside of the upper part of the cylindrical body 121A, a male threaded portion 162 provided on the upper part of the base 161, and a hole portion 163 formed so that the axial pipe 121F can pass through.

[0056] The seal member 152 provides a seal between the shaft pipe 121F and the hole 163. The seal member 153 provides a seal between the shaft portion 151a and the main body 120. The seal member 154 provides a seal between the head portion 151b and the main body 120. The seal member 155 provides a seal between the shaft portion 151a and the hole 121A1.

[0057] The dome-shaped portion 170 is a dome-shaped member formed on the inside of the bottom of the main body 120 so as to cover the upper portion (head portion 151b) of the lid portion 151 and the upper portion (male thread portion 162) of the inner lid 160. A pressure adjustment unit is connected to the space 171 surrounded by the dome-shaped portion 170, the head portion 151b, and the male thread portion 162 via a pipe (not shown). This pressure adjustment unit is capable of generating up to about 1000 atmospheres in accordance with the external seawater pressure. In other words, the pressure adjustment unit is capable of adjusting the air pressure in the space 171 in accordance with the external seawater pressure. This makes it possible to prevent seawater from flowing into the space 171.

[0058] The axial pipe 121F is a fixed shaft with one end sealed and fixed to the main body 120, and corresponds to 21F in the above embodiment. The axial pipe 121F is arranged to be disposed up to the bottom of the cylindrical body 121A with the suction / discharge pipe 123 extending from the inside of the main body 120 passing through it. The tip of the suction / discharge pipe 123 is provided so as to protrude from a lid provided at the other end of the axial pipe 121F, and the internal space of the axial pipe 121F is at atmospheric pressure, the same as the inside of the main body 120.

[0059] Incidentally, even inside the cylinder 121A, the internal pressure may be adjusted to match the external seawater pressure by connecting the space 171 to the pressure adjustment unit through the gap between the axial pipe 121F and the hole 163, or directly through a pipe (not shown), without providing the seal member 152. This makes it possible to prevent seawater from flowing into the space 180 inside the cylinder 121A.

[0060] Such a sealing mechanism 150 allows the main body 120 to support the rotation of the cylindrical body 121A while maintaining the inside of the main body 120 at atmospheric pressure.

[0061] In addition, the drilling machine according to the present invention can use a suction device and a suction / discharge pipe to mine seafloor hydrothermal deposits, that is, to recover gold or rare metals by sucking up steam rising from magma.

[0062] Furthermore, the excavator according to the present invention has improved diving capabilities compared to conventional ones, making it possible to work in areas 2000m to 3000m deeper than conventional submarine diving areas. Also, the submersible according to the present invention has improved diving capabilities compared to conventional ones, making it possible to dive 2000m to 3000m deeper than conventional submarine diving areas.

[0063] Second embodiment Hereinafter, an excavator and a resource recovery system according to a second embodiment of the present invention will be described with reference to the drawings. In this embodiment, the reference numbers having the same last two digits as those in the first embodiment are similar, and therefore their explanations may be omitted. In addition, as for the parts that are not particularly described, they are similar to those in the excavator and the resource recovery system according to the first embodiment, and therefore their explanations and illustrations may be omitted.

[0064] As shown in FIG. 7, the resource recovery system 201 according to this embodiment includes: The present embodiment is provided with an excavator 202 instead of the excavator 2 of the first embodiment, and further includes a mobile boat 290 and a mobile boat 291. The main difference from the resource recovery system 1 according to the first embodiment is that in this embodiment, four excavators 202 are installed. Note that in Fig. 7, illustration of offshore rigs and the like is omitted.

[0065] The mobile craft 290 is connected to the submarine pipeline 206 on the side of the drilling machine 202 closer to the adjustment building 207. The mobile craft 290 has a screw (not shown) and is capable of moving in water and also capable of stopping in water.

[0066] The mobile boat 291 is connected to the submarine pipeline 206 on the side closer to the excavator 202 than the mobile boat 290. The mobile boat 291 has a screw (not shown) and is capable of moving in water and also capable of stopping in water.

[0067] The submarine pipeline 206 has a soft material between the adjustment tower 207 and the mobile boat 290, and between the mobile boat 290 and the mobile boat 291. This allows the excavator 202 to be moved by moving the mobile boat 290 and the mobile boat 291 without moving the adjustment tower 207 (see the two-dot chain line in FIG. 7).

[0068] In addition, the submarine pipeline 206 has a rigidity between the mobile boat 291 and the excavator 202. This allows the excavator 202 to move in accordance with the movement of the mobile boat 291, so that the excavator 202 can be easily moved to a desired position.

[0069] The excavator 202 is an excavator that excavates a rare earth-containing mud layer below a seabed mud layer, and includes a main body 220 lowered to the seabed, and a pair of excavation devices 221, 222 provided on the main body 220. In this embodiment, the main body 220 is formed in a cylindrical shape having an axis extending in the horizontal direction.

[0070] In addition, since the excavation devices 221 and 222 are configured as a pair and do not need to be particularly distinguished from each other, in order to simplify the explanation, the following description will focus on only one of the excavation devices 221. The excavation device 222 is disposed symmetrically to the excavation device 221 with respect to the center of the main body 220 in the axial direction.

[0071] As shown in FIG. 8, the excavation device 221 has a cylindrical body 221A, a cutter head 221C, and an axial pipe 221F.

[0072] The upper part of the cylindrical body 221A is fixed to the main body 220, and protrudes downward from the lower part of the main body 220. The axis of the cylindrical body 221A extends in the vertical direction. In this embodiment, the cylindrical body 221A is a cylindrical body.

[0073] The cutter head 221C is rotatably arranged in the lower part of the cylindrical body 221A. The cutter head 221C is rotatable around the axis of the cylindrical body 221A with respect to the cylindrical body 221A and the axial pipe 221F. The cutter head 221C is arranged at a position higher than the lower end position of the cylindrical body 221A by a predetermined distance. The space between the cylindrical body 221A and the cutter head 221C is sealed by a seal member (not shown). The space between the axial pipe 221F and the cutter head 221C is sealed by a seal member (not shown). A pressure adjustment device (not shown) capable of adjusting the internal pressure of the cylindrical body 221A to be the same as the external pressure of the cylindrical body 221A is connected to the inside of the cylindrical body 221A via a pipe from the sea. This prevents liquids from entering the inside of the cylindrical body 221A even when the cutter head 221C is rotating.

[0074] The cutter head 221C has a plurality of (for example, four or eight) spoke portions 221G. The plurality of spoke portions 221G are arranged at equal intervals in the circumferential direction centered on the axis of the cylindrical body 221A. Each of the plurality of spoke portions 221G extends in the radial direction centered on the axis of the cylindrical body 221A. In other words, the axis of each of the plurality of spoke portions 221G extends in the radial direction centered on the axis of the cylindrical body 221A. Each of the four spoke portions 221G is supported rotatably about the axis of the spoke portion 221G.

[0075] As shown in Fig. 9, the cutter head 221C has a plurality of cutter bits 221H. The plurality of cutter bits 221H are disposed on each of the four spoke portions 221G. Note that Figs. 8 and 9 only show the cutter bit 221H disposed on one of the four spoke portions 221G, and do not show the cutter bits 221H disposed on the spoke portions 221G other than the one spoke portion 221G.

[0076] A pair of cutter bits 221H are arranged at an interval of 180 degrees in the circumferential direction centered on the axis of the spoke portion 221G. A plurality of such pairs of cutter bits 221H are arranged at an interval in the axial direction of the spoke portion 221G. The pair of cutter bits 221H is arranged at a position shifted by 60 degrees in the circumferential direction centered on the axis of the spoke portion 221G with respect to a pair of cutter bits 221H arranged one on the inner side in the axial direction of the spoke portion 221G. Each of the plurality of cutter bits 221H rotates together with the spoke portion 221G in which the cutter bit 221H is arranged.

[0077] The cutter head 221C is rotated by a rotation drive unit (not shown) such as the rotation drive unit 21D of the first embodiment. The rotation drive unit is provided, for example, inside the cylindrical body 221A, and is configured to rotate the cutter head 221C to excavate the seabed mud layer and the rare earth mud layer. Specifically, the rotation drive unit rotates the cutter head 221C around the axis of the cylindrical body 221A, and rotates each of the four spoke parts 221G around the axis of the spoke part 221G. As a result, each of the multiple cutter bits 221H rotates around the axis of the spoke part 221G on which the cutter bit 221H is arranged, while rotating around the axis of the cylindrical body 221A. The rotation drive unit is configured to rotate the cutter head 221C in this way to excavate the seabed mud layer and the rare earth mud layer. It is preferable that the cutter head 221C of the excavation device 221 and the cutter head (not shown) of the excavation device 222 are rotated in opposite directions by a hydraulic unit. The cutter head 221C of the excavation device 221 and the cutter head of the excavation device 222 can be operated based on a predetermined program in a control unit (not shown), or can be operated by an operator. The operation data of the operator may be learned by an artificial intelligence (AI), and the cutter head 221C of the excavation device 221 and the cutter head of the excavation device 222 may be operated based on the operation data of the operator while the excavator 202 is excavating.

[0078] As shown in FIG. 8, the axial pipe 221F is disposed in the cylindrical body 221A and aligned with its axis. The axial pipe 221F extends into the main body 220, and the upper part of the axial pipe 221F is located inside the main body 220. The axial pipe 221F is fixed to the main body 220. The cutter head 221C is rotatably attached to the axial pipe 221F. The rare earth mud obtained by excavating the rare earth mud layer by rotating the cutter head 221C is pumped into the main body 220 through the suction pipe 223A in the axial pipe 221F. In addition, the cement stored in the cement storage 220G and the residue stored in the spheres 220J are discharged from the lower part of the cylindrical body 221A through the discharge pipe 223B in the axial pipe 221F. The suction pipe 223A and the discharge pipe 223B are provided so as to protrude from the main body 220 toward the excavation device 221.

[0079] Inside the main body 220, there are provided a suction device (vacuum device) 220A, a separation device 220B, a collection section 220C, a cement storage tank 220G, three spherical bodies 220H, 220I, and 220J, and a plurality of plate materials 220K. The suction device (vacuum device) 220A, the separation device 220B, the cement storage tank 220G, and the three spherical bodies 220H, 220I, and 220J are provided for the excavation device 221. Although not shown in the figure, the suction device (vacuum device), the separation device, the cement storage tank, and the three spherical bodies are provided for the excavation device 222, symmetrically with respect to the center of the axial direction of the main body 220.

[0080] The suction device 220A is configured to suck up the rare earth mud obtained by excavating the rare earth mud layer with the cutter head 221C. The suction device 220A is connected to the suction pipe 223A, and the rare earth mud obtained by excavating the rare earth mud layer with the cutter head 221C is sucked from the tip of the suction pipe 223A (see the thick solid arrow in FIG. 8). An opening and closing valve (not shown) is provided at the tip of the suction pipe 223A, and is configured to open when suction is performed by the suction pipe 223A and close when suction is not performed by the suction pipe 223A.

[0081] Separator 220B is configured to separate granules containing rare earths from the rare earth mud sucked into main body 220. Separator 220B is connected to suction device 220A via piping, and the rare earth mud sucked into suction device 220A is supplied to separator 220B through the piping (see the thick solid arrow in FIG. 8), and the granules containing rare earths are separated from the rare earth mud by separator 220B. In this embodiment, the mud is separated into granules and muddy water by a centrifugal separation process using a centrifuge.

[0082] The collecting section 220C is a part (part of the transporting device) that collects the granules separated by the separating device 220B and then transports them using a pump or the like so that they can be collected in the eluate collection building of the offshore rig via the above-mentioned subsea pipeline 206 (part of the transporting device). The collecting section 220C is disposed in the center of the axial direction of the main body 220. The collecting section 220C is connected to the separating device 220B via a pipe, and the granules separated by the separating device 220B are supplied to the collecting section 220C through the pipe (see the thick dashed line arrow in FIG. 8). Although not shown in the figure, the collecting section 220C is also connected to the separating device 220B disposed inside the sphere 220H via a pipe. The granules transported to the sea are subjected to leaching treatment on the spot by a leaching treatment device (not shown). In the leaching treatment, a leaching liquid is used for the solid components containing rare earths. For example, dilute hydrochloric acid is used as the leaching liquid. The leaching eluate treated in the leaching treatment device is transported to land by transport ship.

[0083] Cement storage 220G stores the cement discharged from the lower part of cylinder 221A. Cement storage 220G is connected to discharge pipe 223B, and the cement stored in cement storage 220G passes through discharge pipe 223B and is discharged from the tip of discharge pipe 223B (see the thick dashed arrow in FIG. 8), and is discharged from the lower part of cylinder 221A. An opening / closing valve (not shown) is provided at the tip of discharge pipe 223B, and is configured to open when cement is discharged from discharge pipe 223B and close when cement is not discharged from discharge pipe 223B.

[0084] The three spherical bodies 220H, 220I, and 220J are aligned in the axial direction of the main body 220. Each of the three spherical bodies 220H, 220I, and 220J is hollow. The three spherical bodies 220H, 220I, and 220J are in contact with the inner surface of the main body 220 and fixed to the main body 220.

[0085] Among the three spheres 220H, 220I, and 220J, the middle sphere 220H (first sphere) has therein a suction device 220A, which also serves as a temporary storage tank, a separator 220B, and a cement storage tank 220G. The sphere 220H is disposed above the excavation device 221. The residue from which the granules have been separated by the separator 220B disposed inside the sphere 220H is temporarily stored inside the sphere 220H and is sent to the sphere 220J via a pipe (not shown).

[0086] A separator 220B is disposed inside the spherical body 220I (second spherical body), which is disposed at a position closer to the center of the axial direction of the main body 220 than the spherical body 220H (first spherical body) among the three spherical bodies 220H, 220I, and 220J. The residue from which the particles have been separated by the separator 220B disposed inside the spherical body 220I is temporarily stored inside the spherical body 220I and is sent to the spherical body 220J via a pipe.

[0087] Of the three spheres 220H, 220I, and 220J, 220J (third sphere), which is disposed at a position farther from the center of the axial direction of the main body 220 than sphere 220H (first sphere), is a residue storage configured to store the residue from which the granules have been separated by separator 220B. In sphere 220J, muddy water separated by separator 220B is stored for reuse as backfill material. Sphere 220J is connected to sphere 220H via a pipe (not shown), and the residue stored in sphere 220H is sent to sphere 220J via the pipe and stored in sphere 220J. In addition, the sphere 220J is connected to the sphere 220I via a pipe, and the residue stored in the sphere 220I is sent to the sphere 220J via the pipe (see the thick two-dot chain line arrow in FIG. 8) and stored in the sphere 220J. The residue stored in the sphere 220J is discharged from the lower part of the cylindrical body 221A. The sphere 220J is connected to the discharge pipe 223B, and the residue stored in the sphere 220J is discharged from the tip of the discharge pipe 223B through the discharge pipe 223B (see the thick two-dot chain line arrow in FIG. 8) and discharged from the lower part of the cylindrical body 221A. After the cutter head 221C finishes excavating the rare earth mud layer, the residue is backfilled in the recess formed by the excavation. Then, the cement stored in the cement storage tank is discharged and covered over the area where the residue is backfilled. In addition, an opening / closing valve (not shown) is provided at the tip of the discharge pipe 223B, and the opening / closing valve is configured to open when residue is discharged from the discharge pipe 223B and to close when residue is not discharged from the discharge pipe 223B.

[0088] In addition, a pressure-transport device consisting of a pressurized air lift pump or the like, and an on-off valve, etc. may be provided as appropriate in each pipe of the system for transporting rare earth mud, granules, leaching eluate, residue, cement, etc.

[0089] The plurality of plate materials 220K are members that increase the strength of the main body 220. The plurality of plate materials 220K are arranged side by side in the axial direction of the main body 220. In this embodiment, the plurality of plate materials 220K are arranged side by side without any gaps in the axial direction of the main body 220, but may be arranged side by side with gaps. Each of the plurality of plate materials 220K is arranged so that the axial direction of the main body 220 is the thickness direction of the plate material 220K. Each of the plurality of plate materials 220K has a through hole or the like formed as appropriate so as not to interfere with the spherical bodies 220H, 220I, 220J, piping, or the like.

[0090] As described above, the excavator and resource recovery system of this embodiment make it possible to efficiently recover rare earths at sea.

[0091] Hereinafter, an excavator and a resource recovery system according to a modified example of the second embodiment of the present invention will be described with reference to the drawings. In this modified example, the reference numerals having the same last two digits as those in the second embodiment are similar, and therefore their explanations may be omitted. In addition, the parts that are not particularly described are similar to those in the excavator and the resource recovery system according to the second embodiment, and therefore their explanations and illustrations may be omitted.

[0092] As shown in Fig. 10, the resource recovery system according to this modification is mainly different from the resource recovery system 201 according to the second embodiment in that an excavator 302 is provided instead of the excavator 202 (see Fig. 8) of the second embodiment. Note that an offshore rig and the like are not shown in Fig. 10.

[0093] The excavator 302 differs from the excavator 202 (see Figure 8) of the second embodiment described above mainly in that it is equipped with an excavator 321 instead of the excavator 221 (see Figure 8) of the second embodiment described above, and in that it is equipped with an excavator (not shown) arranged symmetrically to the excavator 321 instead of the excavator 222 (see Figure 7) of the second embodiment described above.

[0094] The drilling device 321 differs from the drilling device 221 (see Figure 8) of the second embodiment described above mainly in that it has a cutter head 321C instead of the cutter head 221C (see Figure 8) of the second embodiment described above, has an axial pipe 321F instead of the axial pipe 221F (see Figure 8) of the second embodiment described above, and further has opening / closing valves 321I, 321J and opening / closing drive units 321K, 321L.

[0095] The cutter head 321C differs from the cutter head 221C (see FIG. 8) of the second embodiment mainly in that the cutter head 321C has a space therein in which the on-off valves 321I and 321J and the on-off drive parts 321K and 321L are disposed.

[0096] The axial pipe 321F is shorter than the axial pipe 221F of the second embodiment (see Figure 8) described above, and differs mainly in that the opening and closing valves 321I and 321J are attached to the tip end so as to be slidable in the left-right direction of the paper in Figure 10 (see the left-right arrows near the members indicated by the symbols 321I and 321J in Figure 10).

[0097] The suction pipe 323A differs mainly from the suction pipe 223A (see Figure 8) of the second embodiment described above in that it is shorter than the suction pipe 223A (see Figure 8) of the second embodiment described above and is positioned so as not to protrude downward below the lower end of the axial pipe 321F.

[0098] The discharge pipe 323B differs mainly from the discharge pipe 223B (see FIG. 8) of the second embodiment described above in that it is shorter than the discharge pipe 223B (see FIG. 8) of the second embodiment described above and is positioned so as not to protrude downward beyond the lower end of the axial pipe 321F.

[0099] The on-off valves 321I and 321J are attached to the shaft pipe 321F by means of attachment members or the like (not shown) so as to be slidable in the left-right direction of the paper of FIG. 10 (see the left-right arrows near the members denoted by symbols 321I and 321J in FIG. 10). Specifically, the on-off valve 321I is attached so as to be slidable in a closed position where the suction port of the suction pipe 323A is blocked, and in an open position where the suction port of the suction pipe 323A is not blocked. The on-off valve 321J is attached so as to be slidable in the left-right direction of the paper of FIG. 10 (see the left-right arrows near the members denoted by symbols 321I and 321J in FIG. 10) so as to be positioned in a closed position where the discharge port of the discharge pipe 323B is blocked, and in an open position where the discharge port of the discharge pipe 323B is not blocked. Here, as a modified example, the on-off valves 321I and 321J may be magnets or electromagnets that attract each other.

[0100] The opening / closing drive unit 321K is attached to the opening / closing valve 321I by a mounting member or the like (not shown). The opening / closing drive unit 321L is attached to the opening / closing valve 321J by a mounting member or the like (not shown). The opening / closing drive units 321K, 321L are composed of, for example, a hydraulically driven hydraulic unit (e.g., a hydraulic motor) and a transformer or the like that serves as its power source. Note that a pressurizing device may be provided so that the internal space of the cutter head 321C in which the opening / closing drive units 321K, 321L are provided can be pressurized according to the external environment (for example, pressurized according to the water pressure outside the excavation device 321).

[0101] When rare earth mud is sucked from suction pipe 323A, opening / closing drive unit 321K slides opening / closing valve 321I leftward in the plane of FIG. 10 to position it in an open position that does not block the suction port of suction pipe 323A. Also, when rare earth mud is sucked from suction pipe 323A, opening / closing drive unit 321L slides opening / closing valve 321J to position it in a closed position that blocks the discharge port of discharge pipe 323B.

[0102] When discharging residue or cement from discharge pipe 323B, opening / closing drive unit 321K slides opening / closing valve 321I to position it at a closed position that blocks the suction port of suction pipe 323A. Also, when discharging residue or cement from discharge pipe 323B, opening / closing drive unit 321L slides opening / closing valve 321J to position it at an open position that does not block the discharge port of discharge pipe 323B.

[0103] When the excavator 302 is moving, the opening / closing drive unit 321K slides the opening / closing valve 321I to position it at a closed position to close the suction port of the suction pipe 323A. Also, when the excavator 302 is moving, the opening / closing drive unit 321L slides the opening / closing valve 321J to position it at a closed position to close the discharge port of the discharge pipe 323B.

[0104] As described above, the excavator and resource recovery system of this embodiment make it possible to efficiently recover rare earths at sea.

[0105] Third embodiment Hereinafter, an excavator and a resource recovery system according to a third embodiment of the present invention will be described with reference to the drawings. In this embodiment, the reference numbers having the same last two digits as those in the above-mentioned embodiments and the above-mentioned modified examples are similar, and therefore their description may be omitted. In addition, as for the parts that are not particularly described, they are similar to the excavator and the resource recovery system according to the above-mentioned embodiments and the above-mentioned modified examples, and therefore their description and illustration may be omitted.

[0106] As shown in FIG. 11, the resource recovery system according to this embodiment is mainly different from the resource recovery system according to the modified example of the second embodiment in that it includes an excavator 402 instead of the excavator 302 (see FIG. 10) of the modified example of the second embodiment. Although not shown, the resource recovery system according to this embodiment includes a mobile boat similar to the mobile boats 290 and 291 of the second embodiment, and is configured so that a main body 420 of the excavator 402 and an excavation device 421 described later can be moved together by moving the mobile boat. As a modified example, a plurality of screws similar to the screw 20F of the first embodiment may be provided on the outer circumferential surface of the main body 420 of the excavator 402 described later, and the main body 420 and the excavation device 421 can be moved together by operating the screws.

[0107] 11, the excavator 402 includes an excavation device 421 that can be lowered to the seabed and excavate the seabed mud layer and the rare earth mud layer, and a main body 420 that is disposed above the excavation device 421 at a predetermined distance in the sea and connected to the excavation device 421 via an axial pipe 421F. Although not shown in the figure, the excavator 402 includes an excavation device that is disposed symmetrically to the excavation device 421 with respect to the center of the axial direction (horizontal direction) of the main body 420.

[0108] The excavator 402 has, inside the main body 420, a suction device 420A for sucking rare earth mud obtained by excavating a rare earth mud layer with a cutter head 421C of the excavation device 421 described later, a separation device 420B for separating granules containing rare earth from the rare earth mud sucked into the main body 420 by the suction device 420A, a collection section 420C for collecting the granules separated by the separation device 420B and then transporting the granules using a pump or the like so that they are recovered to the eluate recovery building of the offshore rig via the submarine pipeline 406, and a cement storage 420G for storing cement discharged from the lower part of the cylindrical body 421A of the excavation device 421 described later. Also, inside the main body 420 of the excavator 402, three spherical bodies 420H, 420I, 420J and a plurality of plate materials 420K are provided, as in the modified example of the second embodiment described above.

[0109] The excavation device 421 has a cylindrical body 421A, a cutter head 421C rotatably arranged inside the lower part of the cylindrical body 421A, and opening / closing valves 421I and 421J and opening / closing drive units 421K and 421L arranged in the internal space of the cutter head 421C. The cutter head 421C, the opening / closing valves 421I and 421J, and the opening / closing drive units 421K and 421L are the same as those in the modified example of the second embodiment.

[0110] The upper part of the shaft pipe 421F is connected and fixed to the lower part of the main body 420, and the lower part is connected and fixed to the upper part of the cylindrical body 421A. The upper end part of the shaft pipe 421F is located inside the spherical body 420H of the main body 420. The lower end part of the shaft pipe 421F is located inside the lower part of the cylindrical body 421A, and a cutter head 421C is rotatably provided thereon. On-off valves 421I and 421J are attached to the tip of the lower end side of the shaft pipe 421F so as to be slidable in the left-right direction of the paper plane of FIG. 11 (see the left-right arrows near the members denoted by symbols 421I and 421J in FIG. 11).

[0111] Inside the axial pipe 421F, a long cylindrical suction pipe 423A and a discharge pipe 423B are provided along the axis of the axial pipe 421F. The suction pipe 423A is arranged from the suction device 420A in the spherical body 420H to the lower end of the axial pipe 421F in the lower part of the cylindrical body 421A, and is for transporting the rare earth mud obtained by excavating the rare earth mud layer by rotating the cutter head 421C to the suction device 420A. The discharge pipe 423B is arranged from inside the spherical body 420J through the spherical body 420H to the lower end of the axial pipe 421F in the lower part of the cylindrical body 421A, and is for transporting the residue stored in the spherical body 420J and the cement stored in the cement storage 420G in the spherical body 420H to the lower end of the axial pipe 421F. In addition, after excavation of the rare earth mud layer is completed, a pressure-feeding device consisting of a pressurized air lift pump or the like may be appropriately provided inside the axial pipe 421F in order to send residue and cement to the recess formed by the excavation through the discharge pipe 423B.

[0112] A pumping device (not shown) composed of, for example, a pressurized air lift pump is provided inside the lower end of the axial pipe 421F, and this pumping device is configured to pump the rare earth mud obtained by excavating the rare earth mud layer through the suction pipe 423A to the suction device 420A in the spherical body 420H, which is a temporary storage tank. The suction pipe 423A is formed so that its internal volume can reduce the pressure of the rare earth mud or resources sucked by the suction device 420A. For example, the axial length (vertical direction) of the suction pipe 423A is set to a length that can reduce the pressure (water pressure) of the rare earth mud in the suction pipe 423A to a predetermined pressure or lower before the rare earth mud is transported from the lower end (tip) of the suction pipe 423A to the suction device 420A in the spherical body 420H. That is, in the excavator 402 of this embodiment, the high-pressure rare earth mud present in the deep sea is depressurized as it passes through the internal space of the suction pipe 423A and is transported to the suction device 420A in the sphere 420H, so that it is possible to prevent the suction pipe 423A from breaking during the mud lifting and the rare earth mud from leaking into the sea. Here, as a modified example, the suction pipe 423A may be formed in a spiral shape or a so-called zigzag shape (a straight line bent multiple times in a Z-shape).

[0113] In the present embodiment, the excavator 402 has, for example, an axial length of 120 m, an inner diameter of 60 cm, a radial thickness of 15 cm, and a volume of 468 m 3When about 44.8 tons of rare earth mud is collected from the seabed at a depth of about 5,500 m into the main body 420 using the suction pipe 423A, first, the opening / closing valve 421I is opened by the opening / closing drive unit 421K, and rare earth mud at 550 atmospheres (water pressure) is forced into the lower end (tip) of the suction pipe 423A by the rotation of a plurality of cutter bits (not shown, but similar to the cutter bits 221H of the second embodiment) provided on the cutter head 421C. Next, the opening / closing valve 421I is closed by the opening / closing drive unit 421K, and the rare earth mud transported from the lower end side to the upper end side of the suction pipe 423A and reaching the suction device 420A in the spherical body 420H by the operation of the suction device 420A in the spherical body 420H and the pumping device in the lower end of the axial pipe 421F is reduced to about 52 atmospheres. Then, when the volume of the suction pipe 423A reaches 38 m, the pressure of the suction pipe 423A is reduced to about 52 atmospheres. 3 When about 22 tons of rare earth mud is forced into the suction device 420A, which is a temporary storage tank for the rare earth mud, the pressure of the rare earth mud drops to about 30 atmospheres or less. The rare earth mud below about 30 atmospheres is then supplied to the separation device 420B, which is connected to the suction device 420A via a pipe, and the rare earth mud is separated into granules and muddy water by a centrifugal separation process using a centrifuge. Then, as in the second embodiment, the granules separated from the rare earth mud are collected by the collection unit 420C and transported to the eluate collection building of the offshore rig via the subsea pipeline 406 for collection.

[0114] As described above, the excavator and resource recovery system of this embodiment can prevent the risk of rare earth mud leaking into the sea during mud pumping, and can recover rare earths stably and efficiently at sea.

[0115] The present invention can also be used to extract methane gas from methane hydrate. In addition, the drilling device of the present invention can be replaced with a crushing type device (a method using a large-diameter drill, a method using a suspended vertical drilling machine, etc.) to extract methane gas from methane hydrate. [Explanation of symbols]

[0116] 1, 201 Resource recovery system 2, 202, 302, 402 Excavator 3. Offshore Rig 4. Elution Collection Building 5. Gas Turbine Power Plant 6, 206, 406 Subsea Pipeline 7, 207 Adjustment Building 20, 30, 120, 220, 420 Body 20A, 120A, 220A, 420A suction device 20B, 220B, 420B separation equipment 20C Leaching treatment equipment 20D Residue Storage 20E Reverse feed device 20F, 35 screw 21, 22, 221, 222, 321, 421 Drilling rigs 21A, 22A, 121A Cylinder 21B, 22B, 121B Fins 21C, 22C, 221C, 321C, 421C Cutter Head 21D, 22D Rotation drive unit 21E, 22E Pressure feed device 21F, 22F, 121F, 221F, 321F, 421F Axle pipe 23, 123 Suction / discharge pipe 24, 41 Pipes L1, L3, L31, L33 reinforced composite layer L2, L4, L32, L34 Steel layers 36 First Tank 37 Second Tank 38 Pump 39 Regulating valve 40a, 40b conduit 100 Submarines 121A1, 151c, 163 holes 150 Sealing mechanism 151 Lid 151a Shaft 151b Head section 152, 153, 154, 155 Seal members 160 Inner lid 161 Foundation 162 Male thread 170 Dome-shaped part 171, 180 space 220C, 420C Collection Section 220G, 420G Cement Storage 220H, 220I, 220J, 420H, 420I, 420J spherical body 220K, 420K plate material 221A, 421A cylinder 221G, 421G spokes 221H Cutter Bit 223A, 323A, 423A suction tube 223B, 323B, 423B discharge pipe 290, 291 Mobile boat 321I, 321J, 421I, 421J On-off valve 321K, 321L, 421K, 421L Opening and closing drive unit

Claims

1. A drilling machine comprising: a pair of drilling rigs that are lowered to the seabed; and a main body that is disposed above the drilling rigs in the sea at a predetermined distance and connected to the drilling rigs via a suction pipe and a discharge pipe, the drilling machine excavating a rare earth mud layer containing rare earths or a resource layer containing minerals that is located under a seabed mud layer, The drilling device includes a cylinder body, a cutter head rotatably disposed in a lower portion of the cylinder body, having The internal space of the cutter head is provided with an on-off valve provided at the tip of the suction pipe and the discharge pipe, Inside the body, A suction device that sucks the rare earth mud or resources obtained by excavating the rare earth mud layer or the resource layer with the cutter head through the suction pipe; A separation device that separates particles containing the rare earth or the mineral from the rare earth mud or the resource sucked by the suction device; a transport device that transports the particles separated by the separator to sea; a residue storage facility for storing the residue from which the particles are separated by the separation device; a cement storage tank for storing cement discharged from the lower portion of the cylindrical body through the discharge pipe, An excavator characterized in that the suction pipe has an internal volume formed so as to be capable of reducing the pressure of the rare earth mud or the resource sucked by the suction device.

2. The main body is formed in a cylindrical shape having an axis extending in a horizontal direction, The main body further includes three hollow spherical bodies aligned in the axial direction of the main body, The suction device, the separation device, and the cement storage tank are arranged inside a first spherical body in the middle of the three spherical bodies, The separation device is disposed inside a second spherical body, which is disposed at a position closer to the center of the main body in the axial direction than the first spherical body, of the three spherical bodies; The excavator according to claim 1, characterized in that a third spherical body, which is one of the three spherical bodies and is located farther from the center of the axial direction of the main body than the first spherical body, is the residue storage tank.

3. An excavator according to claim 1 or 2; An offshore rig installed offshore; A leachate collection building provided on the offshore rig; a submarine pipeline connecting the main body of the drilling machine and the offshore rig; Equipped with A resource recovery system characterized in that the leaching eluate treated in the leaching treatment device of the main body is recovered to the eluate recovery building of the offshore rig via the subsea pipeline.

Images