US3456371A - Process and apparatus for mining deposits on the sea floor - Google Patents
Process and apparatus for mining deposits on the sea floor Download PDFInfo
- Publication number
- US3456371A US3456371A US453784A US3456371DA US3456371A US 3456371 A US3456371 A US 3456371A US 453784 A US453784 A US 453784A US 3456371D A US3456371D A US 3456371DA US 3456371 A US3456371 A US 3456371A
- Authority
- US
- United States
- Prior art keywords
- pipe
- tractor
- dredge pipe
- sea floor
- dredge
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000005065 mining Methods 0.000 title description 24
- 238000000034 method Methods 0.000 title description 18
- 230000008569 process Effects 0.000 title description 12
- 210000003128 head Anatomy 0.000 description 39
- 230000033001 locomotion Effects 0.000 description 32
- 239000013535 sea water Substances 0.000 description 23
- 239000000203 mixture Substances 0.000 description 15
- 239000000463 material Substances 0.000 description 14
- 238000002347 injection Methods 0.000 description 13
- 239000007924 injection Substances 0.000 description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 6
- 238000004891 communication Methods 0.000 description 6
- 229910052748 manganese Inorganic materials 0.000 description 6
- 239000011572 manganese Substances 0.000 description 6
- 238000011084 recovery Methods 0.000 description 5
- 230000035939 shock Effects 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000011707 mineral Substances 0.000 description 3
- 230000002441 reversible effect Effects 0.000 description 3
- 239000011343 solid material Substances 0.000 description 3
- 241000239290 Araneae Species 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 230000005514 two-phase flow Effects 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 230000002860 competitive effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- -1 for example Inorganic materials 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000013507 mapping Methods 0.000 description 1
- 239000003550 marker Substances 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000037230 mobility Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 210000002445 nipple Anatomy 0.000 description 1
- 230000005019 pattern of movement Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 230000011664 signaling Effects 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000008247 solid mixture Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000012876 topography Methods 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C50/00—Obtaining minerals from underwater, not otherwise provided for
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F3/00—Dredgers; Soil-shifting machines
- E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
- E02F3/88—Dredgers; Soil-shifting machines mechanically-driven with arrangements acting by a sucking or forcing effect, e.g. suction dredgers
- E02F3/8858—Submerged units
Definitions
- nodules contain manganese and iron in substantial quantity, and in addition, valuable amounts of copper, cobalt, nickel, and other metals.
- the nodules vary in size and shape. They tend to be spherical, and their largest dimension may be up to about eight inches or larger. The economic recovery of these nodules poses several challenging problems.
- One object of the present invention is to provide a new and practical process for mining deposits on the sea floor.
- a related object of the invention is to provide practical equipment for practicing this process.
- a more specific object of the invention is to provide practical processes and devices for the economic recovery of manganese nodules from sea floor deposits.
- Another object of the invention is to provide new and practical techniques for transporting liquid-solid mixtures upwardly from the sea floor, through relatively long lengths of dredge pipe.
- a further object of the invention is to provide new and practical techniques for mining valuable deposits that are distributed on the surface of the sea floor and that are embedded in the first few inches or feet of the sea floor.
- Still another object of the invention is to provide efficient, effective techniques and equipment for recovering manganese nodules from the sea floor, at costs that can be economically competitive considering the value of the recoverable minerals that are available in the nodules.
- FIGURE 1 is a fanciful, fragmentary view showing a surface vessel underway on the surface of the sea, a gathering vehicle for movement on the sea floor, and an articulated dredge pipe interconnecting the surface vessel and the gathering vehicle, all in accordance with one preferred embodiment of the present invention
- FIGURE 2 is a fragmentary side elevation on an enlarged scale, of the gathering vehicle on the sea floor
- FIGURE 3 is atop plan view thereof
- FIGURE 4 is a fragmentary section taken on the line 44 of FIGURE 3, looking in the direction of the arrows;
- FIGURE 5 is a fragmentary side elevation, partly broken away, of a section of the dredge pipe and an adjacent and connected section of a compressed air pipe, that communicates with a jacket about the dredge pipe for injecting air under pressure into the dredge pipe;
- FIGURE 6 is a sction taken on the line 66 of FIG- URE 5, looking in the direction of the arrows;
- FIGURE 7 is a fragmentary part elevation, part section, of the receiving tank into which the dredge pipe discharges when an air lift is employed to transport the mined nodules mixed with sea water through the dredge
- FIGURE 8 is a fragmentary part side elevation, part vertical section, on an enlarged scale, of different kinds of joints that are employed between adjacent sections of the dredge pipe;
- FIGURE 9 is a side elevation of a pump, and of a cage in which it is mounted, for producing a hydraulic lift to transport mined material upwardly through the dredge pipe, with the direction of flow indicated by arrows;
- FIGURE 10 is a fragmentary side elevation of a surface vessel for supporting the dredge pipe and temporarily storing the mined nodules, and
- FIGURE 11 is a fanciful elevation showing the gathering vehicle in a series of different positions through which it would be moved when hoisted from the sea floor up into the surface vessel, or vice versa.
- the numeral 14 denotes generally a gathering vehicle or tractor that is designed for movement over the floor of the sea.
- a surface vessel 15 is shown under way on the surface of the sea, in proximity to the position of the tractor.
- a dredge pipe 16 is suspended from the vessel 15, and is buoyed up by multiple buoyancy tanks 18 that are secured to the dredge pipe at intervals below the surface of the sea.
- the lower end of the dredge pipe forms, under its own weight, a shape that is referred to herein as a catenary 19, although it is recognized that drag and other forces also act on this pipe, so that it is technically not a true catenary.
- a sturdy line 21 is anchored at its lower end to the tractor 14, and is connected at its upper end to a buoy 22 that is shown floating in close proximity to the surface vessel 15.
- the tractor 14 is designed and equipped to be remotely controlled from the surface vessel 15. Its function is to move over the sea floor, following a pattern of back and forth movement, and to skim nodules from the sea floor. Essentially, the tractor performs a strip mining operation.
- the tractor 14 is formed with a rugged metal frame that is, however, formed of a light metal such as, for example, aluminum, to keep the over-all weight low, so that the bearing pressure on the surface of the sea floor will be less than one pound per square inch.
- the frame includes a front cross tube 24, a rear cross tube 25, and a center bracing structure that is generally indicated by the numeral 26 (FIGURE 4), all three of which interconnect the two side beams 28.
- a pair of drive sprockets 29 are mounted at the opposite ends of the front cross tube 24.
- Each of these drive sprockets 29 is connected through its own respective shafting 30 and gear train 31 to its own individual electric drive motor 32.
- Each of these drive motors is individually mounted and rigidly secured on its own platform 34, that is supported on cross braces 35 that extend between the front cross tube 24 and the side beams 28, and between the side beams 28 and the center bracing structure 26, respectively.
- Each motor is independent of the other so that the tracks 38 need not be operating at simultaneously equal speeds or in the same direction.
- a plurality of tires 36 are mounted along each side of the gathering vehicle, and each tire is separately and individually suspended from one of the side beams 28.
- a pair of crawler tracks 38 is mounted, one at each side of the tractor, about the drive sprockets 29 and the tires 36.
- the tires 36 are preferably hollow and filled with liquid, to avoid collapse at operating depths.
- a heavy bumper 39 is secured to the front cross tube 24, and is proportioned to extend across the entire width of the front end of the tractor.
- the bumper 39 projects in advance of the tractor and protects the crawler tracks as well as the tractor body.
- a pair of masts 40 are secured to the center brace 26, at opposite sides of the tractor respectively.
- a cross beam 41 is secured between the upper ends of the masts 40, so that the masts 40 and cross beam 41 together form a structure that is generally in the shape of an inverted U.
- An eye plate 42 is secured centrally on the cross beam 41, to face the front of the vehicle, for a purpose to be described presently.
- a similar eye plate 44 is secured to the upper surface of the cross beam 41, projecting upwardly, to provide anchorage for the pendent line 21.
- the apex of an A-shaped truss 45 is rigidly secured to the rear face of the cross beam 41 at its apex, and each of its legs is rigidly secured to opposite sides respectively of the rear cross tube 25.
- Individually mounted heavy spring rake tines 46 are supported by a cross beam 47.
- the lower, free ends of the rake tines are disposed to project a short distance below the lower surfaces of the crawler tracks 38. This ar- .rangement permits the tines to rake the surface of the sea floor and to deflect by swinging toward the rear and upwardly, upon encountering some unusually large or immovable obstruction.
- a pair of scraper blades 49, 50 are each respectively secured to the center brace 26 of the vehicle frame for pivotal movement about vertical axes by pins 51, 52, respectively. These pins interconnect the frame and the outboard ends of a pair of frontally-disposed web portions 54, 55, that are integral with the scraper blades, respectively. These web portions 54, 55 are in turn pivotally secured by pins 53, 57, respectively, to the pistons of spring plungers 56, 58, repectively, that spring-press the scraper baldes to the diagonal position shown best in FIG- URE 3, in which the two scraper blades converge together toward the rear or trailing end of the tractor.
- the tractor should be protected from damage by sonic or supersonic scanning of its immediate path, and for this purpose, a forward searching sonar unit may be mounted on the tractor. It is also desirable to provide closed system television, with floodlights trained to illuminate the path. The provision of an inclinometer on the tractor, and of a pan and tilt device on the TV camera to permit inclinometer readings, also is desirable. To operate underwater television successfully at depths greater than about 6,000 feet, it may be desirable to install amplifiers in the cable. Water-tight connectors are used for this purpose.
- Each of the crawlers of the tractor preferably is independently driven by its individual motor, as shown in the drawing.
- each crawler can be powered by a 75 H.P. submersible, two speed, reversible electric motor with a built-in gear reduction.
- the tractor may be turned by slowing one of the crawler units, or by going forward on one crawler unit and to the rear on the other.
- the same electric power cable may provide power for a pump for jetting on the sea floor, in the path of the tractor.
- the surface vessel 15 is formed with an open center well 61.
- a pneumatic or hydraulic shock absorber or shock plunger 62 is mounted within this well, and the upper end of the dredge pipe is secured to the shock plunger.
- the dredge pipe is formed from sections that are preferably about eighty feet long, and that are interconnected in the following manner. Over the main portion of the length of the dredge pipe, each of the pipe sections 64 (FIGURE 8) is formed with a flange fitting 65 at each of its ends. The flange fittings of adjacent pipe sections are held together with clamp fittings 66, in watertight fashion.
- ball joints are employed between adjacent pipe sections where required.
- One form of ball joint that may be employed, consists of a female fitting 68 that is welded or otherwise secured to one end of a pipe section. The confronting end of the adjacent pipe section is provided with a mating male fitting 69, that can be received in substantially watertight engagement within the female fitting.
- a clamping collar 70 is secured to the end of the female fitting 68 by a plurality of pivoted bolts 71 that are secured in angularly spaced relation about the female fitting. The collar 70 is proportioned to restrain the two fittings 68, 69 against relative axial movement, While permitting relative rotary movement, in a manner well known in the art.
- the individual sections of the dredge pipe are selected for optimum strength and weight characteristics.
- the lower sections of the dredge pipe, that are secured to the gathering vehicle may be made of welded aluminum.
- the wall thicknesses of the pipe sections may be progressively increased, from the sea floor upward, as needed, to provide adequate strength for supporting the lower pipe sections, and the upper sections of the dredge pipe may be formed from high tensile welded steel, rather than from aluminum.
- buoyancy tanks 18 or other buoyant items or materials are secured to the dredge line, below the surface, to provide support for a substantial part of the weight of the dredge pipe.
- the last section 72 of the dredge pipe is operatively connected to the tractor in the following manner.
- An eye plate 74 (FIGURE 2) is secured to the end of the pipe section 72 that is remote from the tractor, and a line 75 interconnects the eye plate 74 with a ring 76 that is secured in the pendent line 21.
- a collar '78 is mounted intermediate the ends of the pipe section 72. This collar is formed with a pair of eyes, and one line 79 interconnects the collar 78 with the frontfacing eye plate 42 on the cross beam 41 of the tractor, and a second line 80 interconnects the collar with an eye bolt that is secured to the front cross tube 24.
- the pipe section 72 is connected through an L fitting 84 with a flexible ball joint 85, that permits limited move ment of the dredge pipe relative to the tractor.
- the ball joint 85 is mounted on an L 86 (FIGURE 4) that is secured to the center brace 26 of the tractor by a cradle of supporting webs 88.
- the L 86 in turn is connected through a flexible ball joint 89 with a short stub pipe 90 on which the collector head 91 is mounted.
- the collector head 91 is formed with a lower face 92 that confronts the sea floor during normal mining operations.
- This lower face 92 is formed with a large, generally rectangular opening, across which a heavy screen or grille 94 is mounted, to prevent the entrance of undesirably large articles into the dredge pipe.
- a pair of lugs 95 are secured to the opposite respective sides of the collector head, adjacent its upper end.
- a pair of arms 96 are rigidly secured to these lugs, and project toward the rear of the tractor. These arms 96 are formed, at their respective free ends, with massive, slotted guide members 98.
- the rear frame tube of the tractor is slidably received within the slots of these guide members.
- a pair of stop rings 97 are secured on the tube 25, on the outboard sides of the guide members 98 respectively, to limit movement of the guide members lengthwise of the tube.
- the two guide members 98 are rigidly interconnected together by a transverse heel member 99, that is disposed beneath the frame tube 25.
- the heel member 99 is formed with a rounded lower face, to ride on the sea floor, and with an upwardly curved central lip portion 100.
- the lower face of the heel 99 rides over the sea floor, but when an irregularity is encountered, the heel 99 and the guides 98 rise up or drop down, and as they do so, they cause the arms 96 to move correspondingly, carrying the collector head 91 up or down with them.
- At least two buoyancy tanks are ordinarily used, each having a positive buoyancy of at least about 100,000 lbs. These tanks are provided with an initial internal air pressure of about 1,000 p.s.i., before being submerged, attached to sections of the dredge pipe.
- buoyancy tanks can be employed of smaller buoyancy capacity than mentioned above.
- the use of a plurality of such tanks produces a more uniform distribution of stress along the length of the dredge pipe and makes possible the use of less heavy and therefore less strong dredge pipe sections and joints.
- THE AIR LIFT To transport mined material from the surface of the sea floor up through the dredge pipe, it is preferred to employ an air lift.
- This transporting technique utilizes an injection of compressed air into the dredge pipe, at some distance below the sea surface and at some distance above the sea floor, to form within the dredge pipe first a two phase mixture of air and sea water, and then, as operations begin, a three phase mixture of air, sea water, and dredged solid material. These mixtures are lighter than the sea water surrounding the dredge pipe, and the pressure of the surrounding sea water forces the mixture up through the dredge pipe.
- a section 102 of relatively small diameter pipe is secured by straps 104 to each section of dredge pipe, above the air injection site, to carry compressed air to the injection site.
- a quick-disconnect fitting 101 is secured to each end of each air pipe section.
- the quick-disconnect fittings 101, at the end of each air section, are connected to the confronting fittings of adjacent air pipe sections through short, flexible interconnecting flexible nipples 105.
- a special dredge pipe section 106 is provided with an external jacket 108, intermediate its ends.
- the wall of the dredge pipe section 106, that is enclosed within the jacket 108, is formed with a plurality of perforations 109, to admit air from the jacket into the dredge pipe.
- a pair of curved pipes 110 interconnect and provide communication between the lower end of the air pipe 102 and the interior of the jacket 108.
- the dredge pipe is mounted to discharge into a chamber at superatmospheric pressure.
- This chamber is provided in a tank 111 (FIGURE 7) that is mounted on a movable base 112.
- a connecting pipe 114 is mounted to provide communication between the upper end of the dredge pipe, that is suspended from the shock plunger 62, and the tank 111.
- a curved baifie 115 is mounted within the tank chamber, over the discharge opening of the connecting pipe 114, to deflect the stream that is injected into the tank chamber, and to preserve the tank against wear.
- a rotary valve 116 at the bottom of the tank, permits continuous discharge of nodules from the tank, during operations.
- a riser 118 is connected to the tank chamber at its lower end, and is open to the atmosphere at its upper end.
- sliding gates or valves are connected to the pipe, to permit sea Water to run out of the pipe into one or more of several troughs 117, that are secured to the pipe 118 in positions, respectively, to receive the runoff water. This arrangement facilities control over the head that is maintained within the tank 111.
- the tank 111 is maintained at superatmospheric pressure to avoid the pinch effect that would otherwise occur during air lift operations.
- the pinch effect can be explained in the following manner.
- a bubble of air that is rising, under generally isothermal conditions, through several hundred feet of water to the surface, will expand to many times its original volume. For example, if the bubble rises 3400 feet, it will expand to approximately 100 times its original volume. Moreover, 50 percent of the total expansion will take place in the final 34 feet of the ascent, where the static head or back pressure is lowest. Such a tremendous expansion, in the final section of the dredge pipe, could tend to generate unfavorable conditions.
- the surface vessel 15 is provided with a derrick 119 that is mounted over the vessels center well 61, to facilitate handling the dredge pipe sections when raising and lowering, or simply changing the length of, the dredge pipe.
- a crane 120 is mounted adjacent the derrick, for hoisting the pipe sections, and transporting them to and from the storage racks 121, or from supply vessels.
- An A-frame and boom 122 are mounted at the front of the ship, for handling the pendent line 21, when necessary.
- the pressurized discharge tank 111 is mounted adjacent the derrick 119 and the center well 61, to facilitate connecting the dredge pipe for discharge.
- the surface vessel is preferably equipped for dynamic positioning, that makes it possible for the surface vessel to maintain a substantially fixed position on the surface of the sea, for indefinite periods of time, or to move in a predetermined path, as necessary.
- HYDRO-LIFT Instead of using an air lift for transporting material up the dredge pipe, other transport systems can be em ployed.
- a preferred alternative makes use of at least one rotary pump, located in the dredge pipe, for developing enough lifting action to transport mined material effectively.
- the pump 125 is a centrifugal type rock pump having a non-clogging impeller, and is mounted in a particular section 126 of the dredge pipe 16.
- the pump is provided with a pair of discharge pipes 128, that are parallel for a short distance, to provide the inner part of a cage structure about the enclosed submersible electric motor 129 that drives the pump.
- These discharge pipes are connected together above the motor, to communicate with a single section of the dredge pipe.
- an outer cage structure 130 is provided, through which there is no flow, and whose purpose is to provide the supporting structure for the motor and pump, and also to maintain the tensile strength of the dredge pipe.
- More than one pump may be used, as necessary, depending upon the depth of the Water at which mining is 10 taking place. If more than one pump is used, the pumps are mounted and operated in series, The pumps function to generate sufficient Water pressure and velocity so that the nodules, and other solids, are entrained and are transported by the sea water upwardly through the dredge OPERATION Operation of this equipment will now be described, utilizing air-lifting techniques for causing transport of the mined material.
- the surface vessel preferably is equipped with auxiliary equipment and supplies, to permit operations at a substantial distance from land bases, without the need of direct or continuous land-based support other than for transportation of mined materials, food and supplies, and emergency assistance.
- a series of at least four taut line buoys is set to a known and recorded pattern.
- Each of these buoys is equipped with a sonar transponder, battery powered, with a signaling life of several months.
- These initial buoys form the master buoys for the area to be mined, and subsequent mapping and setting of auxiliary marker buoys, of which there will normally be very many, are related to the original master buoys.
- the sonar transponders are serviced and repowered, at regular intervals as needed, by divers.
- the surface vessel 15 is moved into operating position.
- the gathering vehicle or tractor 14 is carried by the surface A vessel, either on deck, in the center well 61, or suspended directly beneath the center well, when operations are pending.
- the tractor 14 is slowly lowered, by adding on the appropriate dredge pipe sections to lengthen the dredge pipe sufficiently to lower the tractor to the sea floor.
- the pendent wire line 21 is held out from the bow of the ship on the boom 122 as the tractor is lowered, and this automatically forms the desired catenary 19 at the lower end of the dredge pipe, as the tractor is lowered to the sea floor.
- the entire weight of the dredge pipe is transferred to a spider (not shown) that is mounted at the level of the main deck of the surface vessel. After the dredge pipe has been secured to the spider," the receiving tank 111 is placed in position and secured in place for operations.
- the swing joint 85 through which the dredge pipe is connected with the tractor, permits the tractor to move in wide sweeps transversely of the direction of travel of the surface vessel. This decreases the required speed of the surface vessel, and results in smaller drag forces on the dredge pipe.
- the movement of the tractor on the surface of the sea floor is remotely controlled from the surface vessel, in order to cause the tractor to move in a predetermined pattern of movement, or as indicated by the topography of the sea floor, to skim the surface of the sea floor in the areas traversed.
- the air lift is placed in operation, to start a current of sea water up through the dredge pipe.
- the sea floor is raked to loosen up the material forming the sea floor, and to free up the manganese nodules.
- the scraper blades 49 and 50 plow all of the nodules, and other solid material, into a bed in the path of the collector head. This bed is immediately traversed by the collector head 91.
- the collector head passes through the bed of nodules and other material from the sea floor, the current of sea water passing into the collector head sweeps the bed up, through the screen in the lower face 92 of the collector head, andthence through the stub pipe and the successive fittings into the dredge pipe.
- the area to be mined should be relatively flat.
- the nodule concentration, of nodules lying on the surface and within the first six inches of depth of the surface of the sea floor is about four pounds per square foot of sea floor surface or greater
- strip mining in accordance with the procedure herein described ordinarily is eifective and efficient.
- the tractor can be driven at a speed of about one or two feet per second, and the rate of recovery of nodules may be on the order of to 200 pounds per second, depending upon the size of the collector head.
- volume of air-quantity c.r.m 10, 600 16, 000 Compressor horsepower to maintain system 1, 800 3, 400 Compressor horsepower total on dredge 4, 000 8, 000 Total flow (slurry), lbs. min 87, 300 87, 300 Total flow (nodules), lbs/min 9, 000 9, 000
- the material discharges into the chamber of the tank 111.
- This chamber is maintained at a superatmospheric pressure, such as, for example, about 22 p.s.i.g. or higher.
- the solids portion of the three phase mixture, that is discharged into the tank 111 settles rapidly.
- the solids are transferred through the rotary valve 116 from the bottom of the tank into a material handling system, such as, for example, a transfer conveyor, that will transfer the solid materials into appropriate hoppers.
- the sea water is allowed to run off and return directly to the sea.
- nodule recovery is based upon nodules having a largest dimension of about 8", about 0.6 sphericity, specific gravity 2.1, and density of about 131 lbs/cu. ft.
- the air injection site preferably is located about 1,375 feet below the surface of the sea, and at the operating injection pressure of 9 355 p.s.i.a., the daily air rate is about 15.4 std. MCF.
- the compressors withdraw air from the tank 111 into which the dredge pipe discharges. This air is then compressed and returned to the dredge pipe at the injection site.
- the compressed air system by flexible, with multiple compressor units, with at least 100 percent of standby capacity, and reserve high pressure air tanks, all capable of delivering compressed air in a wide range of pressure.
- an exemplary dredge pipe string For mining in water depths of up to about 12,000 feet, an exemplary dredge pipe string would be constituted as follows, from the sea floor up:
- the air injection site be located at a depth of at least 1,000 feet blow the surface of the sea.
- centrifugal pumps replace the air injection system, and the dredge pipe discharges directly into the atmosphere instead of into a pressurized discharge chamber.
- two pumps of 1500 HP. each, operating in series, located about 600 feet below the surface of the sea.
- These pumps should be constant speed, A.C. powered pumps, with adequate motors to meet maximum emergency power fluctuations.
- the dredge pipe and tractor can be hauled aboard the surface vessel, as indicated schematically in FIGURE 11.
- the dredge pipe can be disconnected from the surface vessel, but left connected to the buoy 22 through the pendent line 21, and the dredge pipe can simply be laid on the sea floor, for retrieval after the storm.
- a sonar transponder or repeating target is mounted adjacent preselected joints, at intervals along the length of the dredge pipe, and, as well, on the gathering vehicle.
- These units will respond to the ultrasonic sound of a sonar transmitter on the surface vessel, and their transmitted energy will in turn be received on the ship.
- a suitable display of these signals in both plan and elevation, the configuration of the pipe line, and the location of the gathering vehicle relative to the surface vessel, are ascertained.
- This power supply cable is attached to each section of the dredge pipe by means of a suitable quick-connecting clamp.
- cable reels are mounted on the deck of the surface vessel, for stowing and reeling out of the cable.
- the cable preferably is prepared in lengths of approximately 6,000 feet, with watertight connectors at the joints. Amplifiers for the underwater television are inserted in these joints, as needed.
- the composite cable is made up of individual wires as needed for power, lights, electronics and controls, all suitably assembled in one unit and then covered with a moisture-impermeable insulation, protected by double armor, reverse lay wrapping.
- the end of the cable is let out of the center axle of the cable reel, and is terminated in suitable connectors that are connected up for operation after the vehicle is in operative position on the sea floor.
- a device for skimming and collecting deposits from the sea floor comprising:
- tractor means for movement over the sea floor including drive means disposed at opposite sides of said tractor for supporting and driving said tractor on the sea floor;
- collector head that is mounted on said tractor intermediate said drive means and remote from the leading end and rearward of said leading end of the tractor and said collector head having openings on a face thereof opening toward the leading end of said tractor and disposed to receive deposits from the sea floor;
- a pair of scraper blades that are mounted intermediate said drive means, for movement upon movement of said tractor, and that are disposed for skimming the sea floor and that converge together toward said collector head, to direct skimmed deposits toward the collector head, but terminating forwardly of said collector head to provide an outlet for said deposits, said collector head inlet openings being disposed opposite said scraper blade outlet.
- Means for mining deposits from the sea floor comprising, in combination:
- tractor means for movement over the sea floor including drive means disposed at opposite sides of said tractor for supporting and driving said tractor on the sea floor;
- collector head that is mounted on said tractor intermediate said drive means and remote from the leading end and rearward of said leading end of the tractor and said collector head having openings on a face thereof opening toward the leading end of said tractor and disposed to receive deposits from the sea floor;
- a pair of scraper blades that are mounted intermediate said drive means, for movement upon movement of said tractor, and that are disposed for skimming the sea floor and that converge together toward said collector head, to direct skimmed deposits toward the collector head, but terminating forwardly of said collector head to provide an outlet for said deposits, said collector head inlet openings being disposed opposite said Scrapper blade outlet; and means communicating with said dredge pipe intermediate said vehicle and said vessel, for effecting transport of said gathered deposits through said pipe.
- Mining means in accordance with claim 4 wherein the collector head gathers a mixture of said deposits and a volume of sea water to serve as a carrier medium for transporting the deposits and wherein a force generating means is used for generating within said dredge pipe, at a location intermediate its ends, a sufiicient lifting force to cause a continuous flow of said mixture of sea water and deposits upwardly through said pipe.
- Means for mining deposits for the sea floor comprising, in combination:
- collector means mounted on said vehicle, for gathering therein a mixture of said deposits from the sea floor and a volume of sea Water to serve as a carrier medium for transporting the deposits;
- an articulated dredge pipe that communicates with said collector means, for delivering said mixture from said vehicle to said vessel;
- auxiliary pipe means secured to said dredge pipe at least along an upper portion of the length of the dredge pipe, and communicating with said dredge pipe at least at one location intermediate said vehicle and said vessel, to provide communication between said compressor and said dredge pipe, for injecting compressed air into said dredge pipe to effect transport of said mixture of sea water and deposits upwardly through said dredge pipe;
- said dredge pipe being disposed to discharge into said tank under the ambient pressure of the tank; and means permitting the discharge of the sea water and of the gathered deposits from the tank into the atmosphere, while permitting the maintenance of superatmospheric pressure in the tank.
- Means for mining nodular deposits from the sea floor comprising, in combination:
- a self-propelled gathering vehicle comprising tractor means for movement over the sea floor, under remote control from the surface vessel;
- an articulated sectional dredge pipe for delivering gathered deposits from said tractor to said vessel, said dredge pipe being supported at its upper end from said vessel, and said dredge pipe being disposed in the form of a catenary adjacent its lower end, and with a plurality of ball joints intermediate dredge pipe sections respectively along the length of the catenary;
- collector head that is mounted on said tractor and that is disposed for gathering therein a mixture of said deposits and a volume of sea water to serve as a carrier medium for transporting the deposits, said collector head being mounted on said tractor for pivotal movement about a generally horizontal axis thereon, with a free end thereof formed and disposed for sliding movement over obstructions on the sea floor, and wherein said collector head is formed with a collecting opening ahead of its free end in the direction of movement of the tractor, said collecting opening being disposed to confront the gathered deposits;
- interconnecting means interconnecting and providing communication between said collector head and the lower end of said dredge pipe, said interconnecting means being formed to permit horizontal and vertical movement of said dredge pipe relative to said tractor and said,
Landscapes
- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Mechanical Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Earth Drilling (AREA)
- Storage Of Web-Like Or Filamentary Materials (AREA)
- Drilling And Exploitation, And Mining Machines And Methods (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US45378465A | 1965-05-06 | 1965-05-06 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3456371A true US3456371A (en) | 1969-07-22 |
Family
ID=23802048
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US453784A Expired - Lifetime US3456371A (en) | 1965-05-06 | 1965-05-06 | Process and apparatus for mining deposits on the sea floor |
Country Status (4)
Country | Link |
---|---|
US (1) | US3456371A (enrdf_load_stackoverflow) |
BE (1) | BE680695A (enrdf_load_stackoverflow) |
NO (1) | NO123278B (enrdf_load_stackoverflow) |
SE (1) | SE334333B (enrdf_load_stackoverflow) |
Cited By (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3591936A (en) * | 1969-01-15 | 1971-07-13 | Koninkl Mij Tot Het Uitvoeren | Submarine cutter dredger |
US3693272A (en) * | 1969-04-30 | 1972-09-26 | Paul Gariel | A floating tower for underwater dredging |
US3736077A (en) * | 1970-12-28 | 1973-05-29 | E B Dane | Hoist piping for deep-sea mineral slurry |
US3908290A (en) * | 1972-06-22 | 1975-09-30 | Alsthom Cgee | Hydraulic dredging system and method for collecting and removing material from deep sea beds |
US3971593A (en) * | 1973-07-18 | 1976-07-27 | Commissariat A L'energie Atomique | Method of extraction of nodular sediments or the like from the sea floor and an installation for carrying |
JPS51112702A (en) * | 1975-03-31 | 1976-10-05 | Yuuichi Takahashi | Method of mining manganese balls deposited on sea bottom |
US3995889A (en) * | 1975-05-22 | 1976-12-07 | Hydro-Dredge Accessory Co. | Dredge floating pontoon pipe-line joint |
US4052800A (en) * | 1974-08-01 | 1977-10-11 | Salzgitter Ag | System for gathering solids from the ocean floor and bringing them to the surface |
US4160566A (en) * | 1977-02-14 | 1979-07-10 | Kerr-Mcgee Corporation | Mining apparatus |
US4171581A (en) * | 1977-11-14 | 1979-10-23 | Deepsea Ventures, Inc. | Water flow-deflecting shield for dredge suction nozzle |
JPS559520B1 (enrdf_load_stackoverflow) * | 1974-10-19 | 1980-03-10 | ||
US4200999A (en) * | 1978-05-30 | 1980-05-06 | Deepsea Ventures, Inc. | Pivotable means for decreasing drag effects on a generally cylindrical dredge pipe |
US4217709A (en) * | 1978-02-24 | 1980-08-19 | The Research Corporation Of The University Of Hawaii | Submarine sand sampler |
US4652055A (en) * | 1984-08-08 | 1987-03-24 | Preussag Aktiengesellschaft | Device for collecting manganese nodules on the ocean floor |
US4681372A (en) * | 1986-02-11 | 1987-07-21 | Mcclure William L | Deep sea mining apparatus |
US5042959A (en) * | 1988-08-13 | 1991-08-27 | Masao Sakagami | Undersea operation system |
US5199193A (en) * | 1991-12-26 | 1993-04-06 | International Remote Corporation | Working machine |
EP0747540A1 (en) * | 1995-06-08 | 1996-12-11 | Van Oord Acz B.V. | Underwater suction dredging unit and method therefor |
RU2167298C1 (ru) * | 2000-04-04 | 2001-05-20 | Санкт-Петербургский государственный горный институт им. Г.В. Плеханова (Технический университет) | Способ добычи конкреций и устройство для его осуществления |
US6748679B2 (en) | 2002-03-14 | 2004-06-15 | Arthur R. Myers, Jr. | Shellfish dredging apparatus |
RU2306420C1 (ru) * | 2006-04-19 | 2007-09-20 | Государственное образовательное учреждение высшего профессионального образования "Санкт-Петербургский государственный горный институт имени Г.В. Плеханова (технический университет)" | Устройство для добычи конкреций с морского дна |
US20090100724A1 (en) * | 2007-10-18 | 2009-04-23 | Oceaneering International, Inc. | Underwater Sediment Evacuation System |
RU2358105C1 (ru) * | 2007-12-27 | 2009-06-10 | Государственное образовательное учреждение высшего профессионального образования "Санкт-Петербургский государственный горный институт имени Г.В. Плеханова (технический университет)" | Комплекс для добычи конкреций с морского дна |
WO2011156865A1 (en) * | 2010-06-18 | 2011-12-22 | Nautilus Minerals Pacific Pty Ltd | Method and apparatus for auxilary seafloor mining |
NL2006782C2 (en) * | 2011-05-13 | 2012-11-14 | Ihc Holland Ie Bv | Dredger provided with a remotely operable dredging vehicle, and method for dredging using such a dredger system. |
US11794134B2 (en) | 2018-12-20 | 2023-10-24 | Deep Reach Technology, Inc. | Multiphase separation and pressure letdown method |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN107806344A (zh) * | 2017-09-14 | 2018-03-16 | 上海交通大学 | 一种自行式海底矿石收集装置及收集方法 |
CN111287750B (zh) * | 2019-11-26 | 2024-04-19 | 重庆交通大学 | 一种深水采锰结核装置 |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US216686A (en) * | 1879-06-17 | Improvement in pneumatic dredging-tubes | ||
US523838A (en) * | 1894-07-31 | Steam vacuum-dredger | ||
US692815A (en) * | 1900-07-19 | 1902-02-11 | Lindon Wallace Bates | Mouthpiece for suction-dredges. |
US1415113A (en) * | 1920-08-11 | 1922-05-09 | Thomas h | |
US1556128A (en) * | 1923-02-15 | 1925-10-06 | William F Roos | Method of handling material in the presence of compressed air |
US1997149A (en) * | 1931-10-15 | 1935-04-09 | Lake Simon | Submarine locating, harvesting, and recovery apparatus |
FR997304A (fr) * | 1945-07-06 | 1952-01-04 | Perfectionnement aux appareils de draguage et analogues | |
US2826836A (en) * | 1949-02-12 | 1958-03-18 | Richard T Hoffman | Hydraulic dredge |
GB939644A (en) * | 1960-01-20 | 1963-10-16 | Gen Mills Inc | A vehicle for underwater operation |
CA692998A (en) * | 1964-08-25 | Percy S. Gardner, Jr. | Collector and hoist for aggregates | |
US3226854A (en) * | 1963-04-29 | 1966-01-04 | John L Mero | Dredge underwater pick-up head assembly |
US3286286A (en) * | 1964-11-18 | 1966-11-22 | Arthur J Nelson | Pontoon support for over-the-water pipelines |
-
1965
- 1965-05-06 US US453784A patent/US3456371A/en not_active Expired - Lifetime
-
1966
- 1966-05-05 NO NO162895A patent/NO123278B/no unknown
- 1966-05-05 SE SE06180/66A patent/SE334333B/xx unknown
- 1966-05-06 BE BE680695D patent/BE680695A/xx unknown
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US216686A (en) * | 1879-06-17 | Improvement in pneumatic dredging-tubes | ||
US523838A (en) * | 1894-07-31 | Steam vacuum-dredger | ||
CA692998A (en) * | 1964-08-25 | Percy S. Gardner, Jr. | Collector and hoist for aggregates | |
US692815A (en) * | 1900-07-19 | 1902-02-11 | Lindon Wallace Bates | Mouthpiece for suction-dredges. |
US1415113A (en) * | 1920-08-11 | 1922-05-09 | Thomas h | |
US1556128A (en) * | 1923-02-15 | 1925-10-06 | William F Roos | Method of handling material in the presence of compressed air |
US1997149A (en) * | 1931-10-15 | 1935-04-09 | Lake Simon | Submarine locating, harvesting, and recovery apparatus |
FR997304A (fr) * | 1945-07-06 | 1952-01-04 | Perfectionnement aux appareils de draguage et analogues | |
US2826836A (en) * | 1949-02-12 | 1958-03-18 | Richard T Hoffman | Hydraulic dredge |
GB939644A (en) * | 1960-01-20 | 1963-10-16 | Gen Mills Inc | A vehicle for underwater operation |
US3226854A (en) * | 1963-04-29 | 1966-01-04 | John L Mero | Dredge underwater pick-up head assembly |
US3286286A (en) * | 1964-11-18 | 1966-11-22 | Arthur J Nelson | Pontoon support for over-the-water pipelines |
Cited By (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3591936A (en) * | 1969-01-15 | 1971-07-13 | Koninkl Mij Tot Het Uitvoeren | Submarine cutter dredger |
US3693272A (en) * | 1969-04-30 | 1972-09-26 | Paul Gariel | A floating tower for underwater dredging |
US3736077A (en) * | 1970-12-28 | 1973-05-29 | E B Dane | Hoist piping for deep-sea mineral slurry |
US3908290A (en) * | 1972-06-22 | 1975-09-30 | Alsthom Cgee | Hydraulic dredging system and method for collecting and removing material from deep sea beds |
US3971593A (en) * | 1973-07-18 | 1976-07-27 | Commissariat A L'energie Atomique | Method of extraction of nodular sediments or the like from the sea floor and an installation for carrying |
US4052800A (en) * | 1974-08-01 | 1977-10-11 | Salzgitter Ag | System for gathering solids from the ocean floor and bringing them to the surface |
JPS559520B1 (enrdf_load_stackoverflow) * | 1974-10-19 | 1980-03-10 | ||
JPS51112702A (en) * | 1975-03-31 | 1976-10-05 | Yuuichi Takahashi | Method of mining manganese balls deposited on sea bottom |
US3995889A (en) * | 1975-05-22 | 1976-12-07 | Hydro-Dredge Accessory Co. | Dredge floating pontoon pipe-line joint |
US4160566A (en) * | 1977-02-14 | 1979-07-10 | Kerr-Mcgee Corporation | Mining apparatus |
US4171581A (en) * | 1977-11-14 | 1979-10-23 | Deepsea Ventures, Inc. | Water flow-deflecting shield for dredge suction nozzle |
US4217709A (en) * | 1978-02-24 | 1980-08-19 | The Research Corporation Of The University Of Hawaii | Submarine sand sampler |
US4200999A (en) * | 1978-05-30 | 1980-05-06 | Deepsea Ventures, Inc. | Pivotable means for decreasing drag effects on a generally cylindrical dredge pipe |
US4652055A (en) * | 1984-08-08 | 1987-03-24 | Preussag Aktiengesellschaft | Device for collecting manganese nodules on the ocean floor |
US4681372A (en) * | 1986-02-11 | 1987-07-21 | Mcclure William L | Deep sea mining apparatus |
US5042959A (en) * | 1988-08-13 | 1991-08-27 | Masao Sakagami | Undersea operation system |
US5199193A (en) * | 1991-12-26 | 1993-04-06 | International Remote Corporation | Working machine |
EP0747540A1 (en) * | 1995-06-08 | 1996-12-11 | Van Oord Acz B.V. | Underwater suction dredging unit and method therefor |
RU2167298C1 (ru) * | 2000-04-04 | 2001-05-20 | Санкт-Петербургский государственный горный институт им. Г.В. Плеханова (Технический университет) | Способ добычи конкреций и устройство для его осуществления |
US6748679B2 (en) | 2002-03-14 | 2004-06-15 | Arthur R. Myers, Jr. | Shellfish dredging apparatus |
RU2306420C1 (ru) * | 2006-04-19 | 2007-09-20 | Государственное образовательное учреждение высшего профессионального образования "Санкт-Петербургский государственный горный институт имени Г.В. Плеханова (технический университет)" | Устройство для добычи конкреций с морского дна |
US20090100724A1 (en) * | 2007-10-18 | 2009-04-23 | Oceaneering International, Inc. | Underwater Sediment Evacuation System |
US7621059B2 (en) * | 2007-10-18 | 2009-11-24 | Oceaneering International, Inc. | Underwater sediment evacuation system |
RU2358105C1 (ru) * | 2007-12-27 | 2009-06-10 | Государственное образовательное учреждение высшего профессионального образования "Санкт-Петербургский государственный горный институт имени Г.В. Плеханова (технический университет)" | Комплекс для добычи конкреций с морского дна |
WO2011156865A1 (en) * | 2010-06-18 | 2011-12-22 | Nautilus Minerals Pacific Pty Ltd | Method and apparatus for auxilary seafloor mining |
AU2011267842B2 (en) * | 2010-06-18 | 2014-12-04 | Eda Kopa (Solwara) Limited | Method and apparatus for auxilary seafloor mining |
US9260964B2 (en) | 2010-06-18 | 2016-02-16 | Nautilus Minerals Pacific Pty Ltd | Method and apparatus for auxilary seafloor mining |
NL2006782C2 (en) * | 2011-05-13 | 2012-11-14 | Ihc Holland Ie Bv | Dredger provided with a remotely operable dredging vehicle, and method for dredging using such a dredger system. |
US11794134B2 (en) | 2018-12-20 | 2023-10-24 | Deep Reach Technology, Inc. | Multiphase separation and pressure letdown method |
Also Published As
Publication number | Publication date |
---|---|
DE1634854A1 (de) | 1970-08-13 |
NO123278B (enrdf_load_stackoverflow) | 1971-10-25 |
BE680695A (enrdf_load_stackoverflow) | 1966-11-07 |
SE334333B (enrdf_load_stackoverflow) | 1971-04-19 |
DE1634854B2 (de) | 1976-01-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3456371A (en) | Process and apparatus for mining deposits on the sea floor | |
US4479741A (en) | Device for laying underground or digging up subsea conduits | |
US4123858A (en) | Versatile submersible device for dredging or other underwater functions | |
US4685742A (en) | Equipment for extracting ores from sea beds | |
US4232903A (en) | Ocean mining system and process | |
US6273642B1 (en) | Buoyant propulsion underwater trenching apparatus | |
GB1598776A (en) | Unmanned self-propelled submarine vehicle operating at great depth and intended for dredging loading up with polymetallic modules and transporting them to the surface for pelagic fishing and for raising submerged bodies | |
US3697134A (en) | Nodule collector | |
US2731741A (en) | Portable dredge | |
US3950805A (en) | Combination providing safety berthing, unloading of oil, and conduit carriage to refineries on land, of large deep-sea-requiring tankers | |
USRE23963E (en) | Apparatus for laying and retrieving pipe lines | |
US20240417951A1 (en) | Dredging system and method for dredging | |
US3646771A (en) | Underwater communication between a vessel and a structure and vessel-positioning means | |
US20250043886A1 (en) | Seafloor Pipeline Removal System and Method | |
US4085781A (en) | Materials delivery system for offshore terminal and the like | |
US4276846A (en) | Recovery apparatus | |
KR100936941B1 (ko) | 워터제트 고압분사와 펌핑을 병행한 수중굴착 및 매설장치 | |
US2765548A (en) | Marine plow | |
US3975784A (en) | Marine structure | |
US3964423A (en) | Offshore terminal | |
SU1062353A1 (ru) | Пневмогидравлический земснар д | |
US4429476A (en) | Self-immersing jet pump | |
RU2324100C2 (ru) | Способ прокладки подводного трубопровода, система, его реализующая, и монтажный комплекс соединения труб, используемый в ней | |
US3143816A (en) | Undersea mining apparatus with means to establish a pressure balance across the inlet to the conveyor tube | |
CA1278798C (en) | Submersible hydraulic cutter suction dredging system |