AU690173B2 - System for the exploration for and extraction of raw materials, minerals and the like in an underwater bottom - Google Patents

Description

I I System for the exploration for and extraction of raw materials, minerals and the like in an underwater bottom.

The invention relates to a system for the exploration for or extraction of raw materials, minerals or the like in a soft underwater bottom near land, a first cable being stretched between at least one fixed location situated in the water or on the land; and another fixed location, situated at a distance therefrom in the water or on the land, a second cable being stretched between a point on the first cable and a movable location on the land, which location is situated at a distance from said point, which second cable, with the aid of second cable drive means, can be moved, under tension, in the longitudinal direction of the second cable, between the point on the first cable and the movable location, the first and the second cable being oriented at an angle with respect to one another, exploration means or extraction means being attached to a fixed point on the second cable. Such a system is known from GB-A-779 706, in which a scraper is drawn with the above-described cable arrangement along a straight line over a land or underwater bottom.

Exploration and extraction techniques are also, for example, carried out by divers who search an underwater bottom more or less systematically and, on the basis of their observations, decide to remove the bottom material at certain locations, for the purpose of extracting the raw materials, minerals or the like present therein. While this rather primitive method is effective as such, it is very labour intensive. Moreover, divers can only be used in relatively shallow water, such as a surf zone, if the weather is favourable, the water temperature is favourable and the surf or current is not excessive, in order to limit the weighted belts they have to carry with them.

Another manner of extraction in an undersea bottom, as employed in this context, is the so-called tidal or alluvial extraction, which involves forming dams in the sea, which offer sufficient protection against the tidal range to permit extraction. A drawback of this method is AHDEOv~ SNT~ I- -a the necessity of forming depending on the prevailing weather and sea conditions very high, wide and/or long dams which essentially can be accomplished only during the low water period. Moreover, tidal extraction is only applicable in areas where the underwater bottom near the coast is relatively flat and mainly consists of sand, which sand is used for forming the dams.

In deeper water, extraction takes place by use of dredging techniques from ships. These dredgers can, however, only be used in specific favourable weather conditions and outside surf zones, because of the required stability of the ships.

An object of the invention is to provide a system for the exploration for and extraction of raw materials, minerals or the like, which system can be set up and operated rapidly, with very simple means and requiring little labour, covers large areas and functions reliably even under extreme weather and water conditions.

Another object of the inventicn is to provide a system by means of which the extraction can be carried out very selectively.

To these ends, the system according to the invention is characterized in that the first cable with the aid of first cable drive means, can be moved, under tension, between the fixed locations, in the longitudinal direction of the first cable, the point on the first cable being fixed, and means for determining the position of the exploration or extraction means are provided. In an area that is essentially defined by the position of the locations and the course of the coastline or shoreline it is thus possible, first of all, to carry out a systematic exploration of the underwater bottom, it being possible to link measurement results to the position of the exploration means, after which, by means of a similar system, the extraction can be carried out selectively by positioning the extraction means at the deposits, determined on the basis of the exploration measurement results, of the raw materials, minerals or the like. It is observed here that means for determining the position of exploration or AMENDED SHEET 2a extraction means are known per se from GB-A-1 533 822.

Exploration means may use geophysical methods, such as seismological, radiation, sonar, radar and electrical measurements, underground visualisation techniques, or physical methods, such as taking ground samples and carrying out core drilling and borehole measurements.

AMENDED SHEET

II

WO 95/12715 PCT/NL94/00269 3 In a simple preferred embodiment, the first cable runs from a cable drive means at a first location to a cable drive means at a second location. These locations can each be situated both on the land and in the water. For covering a larger exploration and extraction area, the first cable preferably runs from a cable drive means at a first location, via one or more deflection devices at subsequent locations in the water, to a cable drive means at a last location.

The movable location for the second cable is advantageously formed by a vehicle which can be propelled on the land, as a result of which the exploration and extraction means can be moved with a minimum loss of time.

Expediently, the second cable drive means are situated on the vehicle.

Preference is given to cable drive means which consist of winches having a rotatable drum onto which one end of the cable is wound. Such winches can be set up and provided with energy both on the land and in the water on heads situated therein; such winches may also be set up in a movable manner, for example with the aid of vehicles.

A preferred embodiment of a system for the exploration for raw materials, minerals or the like is constructed in such a way that a return idler is attached to the fixed point of the first cable, the second cable, to which exploration means are attached, running from the movable location via the return idler back to the movable or to a fixed location.

A preferred embodiment of a system for the extraction of raw materials, minerals or the like is constructed in such a way that a return idler is attached to the fixed point of the first cable, the second cable, to which extraction means are attached, running from the movable or a fixed location on the land via the return idler to the extraction means which extend as far as the movable location.

More detailed preferred embodiments of the exploration or extraction system according to the invention are specified in the subclaims.

I .I WO 95/12715 PCT/NL94/00269 -4- The invention is explained with reference to the drawing, in which: Figure 1 schematically shows a plan view of the main components of a system for the exploration for raw materials, minerals or the like; Figure 2 schematically shows a p±an view of another embodiment of a system similar to that of Figure 1; Figures 2a, 2b and 2c schematically shows a plan view of yet other embodiments of a system similar to that of Figure 1 or 2; Figure 3 schematically shows a plan view of a vehicle having means for assembling and disassembling a double pipe string, and also having a winch; Figure 4 schematically shows a plan view of a suction head for extracting raw materials and minerals; Figure 5 schematically shows a plan view of the main components of a system for the extraction of minerals and raw materials; and Figure 6 schematically shows a plan view of a detail of Figure 5 on a larger scale, as well as additional system parts to illustrate the operation of the system according to Figure In the figures, identical reference numerals relate to identical components or to components having similar functions. In Figures i, 2, 2a, 2b, 2c, 5 and 6, some of the components shown are depicted disproportionally, for the sake of clarity.

Figure 1 shows an area of a coast or shore, such as a surf zone or a river delta area, the line 2 indicating the transition between land 4 and water 6. In the water 6 there have been placed on the water bottom, at a distance from the land 4, two heads 8a and 8b, for example sunk tanks, or piles driven into the water bottom. The heads 8a and 8b are provided with deflection devices 10a and respectively, for deflecting a cable. The deflection device guides a cable 12a, which at one end is connected to a connection element 14 and at the other end is wound onto the drum of a winch 16a set up on the land 4. The deflection device o10b guides a cable 12b, which at one end WO 95/12715 PCTINL9400269 5 is connected to the connection element 14 and at the other end is wco"nd onto the drum of a winch 16b set up on the land 4. cables 12a and 12b are provided with floats, so that they do not or virtually do not come in contact with the water bottom, and float or are suspended in the water, as far as possible outside the sphere of influence of surf and/or current. The cable may also be made of a material such as perlon, having a specific mass which is approximately equal to that of the water, in order to achieve the same effect. The connection element 14 consists, for example, of a ring to which the cables 12a and 12b are attached. Obviously, the cables 12a and 12b may also form one whole, the element 14 having a suitable different shape. Attached to the connection element 14, by means of a cable 18, there is a return idler 20. A cable 22 is guided over the return idler 20, one end of which cable is wound onto a drum of a winch 24a, and the other end is wound onto a drum of a winch 24b. The winches 24a and 24b are attached to a vehicle 25 which can be propelled in the directions of the double arrow 26. Attached to the cable 22 there is a measuring probe 28 which, so as to stabilize its position, is provided with arms 30 which, at the ends facing away from the measuring probe 28, are coupled to the cable 22 so as to be slidable in the longitudinal direction. Connected to the connection element 14, by means of suitable length of cable 32, there is a buoy 34, for example made of metal. In a similar manner, a buoy 38 is connected to the measuring probe 28 via a cable 36. The cables 12a, 12b and 22 will generally be below the surface of the water, the buoys 34 and 38 marking the position of the connection element 14 and the measuring probe 28, respectively, above the surface of the water. The relative position of the buoys 34 and 38 with respect to marker points on the land 4 can be determined with the aid of radio stations 40a and 40b which are able to detect the buoys. Similarly it is possible, in this manner, to determine precisely the position of heads 8a and 8b and the position of the buoys 34 and 38 with respect to the heads.

It is obviously also possible to determine the absolute Y-s WO 95/12715 PCTINL94/00269 6 position of the measuring probe 28 with the aid of a satellite positioning system.

The measuring probe 28 can be moved between the return idler 20 and the separation line 2 by winding up the cable 22 with the aid of the winch 24b and simultaneously unwinding the cable 22 with the aid of the winch 24a, or in the opposite direction if the direction of rotation of the winches 24a and 24b is reversed. In addition it is possible to move the measuring probe 28 transversely to the direction of the cable 22 in the direction of cable 12b by moving the vehicle 25 in the direction of the winch 16b and essentially simultaneously unwinding the cable 12a from the drum of winch 16a, and winding the cable 12b onto the drum of winch 16b. Por the purpose of moving the measuring probe 28 in the opposite direction, the direction of movement of the vehicle 25 and the directions of rotation of the winches 16a and 16b are reversed. Thus, with the aid of the stationary winches 16a and 16b and the movable winches 24a and 24b, the measuring probe 28 can reach any point within the exploration area bounded by the cables 12a and 12b.

By means of the system according to Figure 1 it is possible to carry out in a simple manner, with the aid of the measuring probe 28, systematic investigations of the water bottom for the presence of raw materials, minerals or the like. To this end, the measuring probe 28 is connected, with the aid of a measuring cable, to measurement processing means set up on the land 4, for example on the vehicle 25. By establishing the position of the measuring probe at each measuring pint, a detailed insight into the local nature of the bottom within the exploration area can be obtained. The exploration area can, for example, be covered by bringing the measuring probe 28 into the vicinity of the return idler'20, bringing the connection element 14 near the deflection device 10a by means of a corresponding displacement of the vehicle 25, then moving the measuring probe 28, while measurements are carried out, in the direction of the cable 22 as far as the separation line 2, then moving the connection element 14 over a predetermined distance in the direction of the deflection WO 95/12715 PCT/NL94/00269 7 device 10b with a corresponding displacement of the vehicle then moving the measuring probe 28 from the separation line 2 as far as the return idler 20, and so forth, so that a meandrous measuring path is gone through.

The heads 8a and 8b may be set up in the water 6 up to a few kilometres from the land 4, the distance between the heads 8a and 8b being 1 km, for example.

Figure 2 shows an embodiment of the system according to the invention, where use is made of only one head 8c with deflection device 10c. Otherwise, the construction and the use of the system is the same as specified with reference to Figure 1.

Figure 2a shows an embodiment of the system according to Figure 2, where winches 16a and 16b are positioned next to one another, as the result of which a more compact system is obtained having shorter power supply and control cables than in the situation shown in Figure 2.

Figure 2b shows an embodiment of the system according to the invention, where winches 16c and 16d for winding and unwinding the cables 12a and 12b have been positioned on the heads 8a and 8b, as a result of which said cables 12a and 12b can be very considerably shorter than in the arrangement shown in Figures i and 2. For the purpose of supplying power to the winches 16c and 16d and controlling them, electricity cables can be laid across the underwater bottom to the heads 8a and 8b. It will be obvious that the two winches 16c and 16d can also be positioned on one of the two heads 8a or 8b, a return idler being arranged on the other head for guiding the cable back to the head with the winches.

Figure 2c shows an embodiment of the system according to the invention, where winches 16e and 16f for winding and unwinding the cables 12a and 12b are set up on the land 4 on either side of a river mouth.

After the exploration has been rounded off and it has therefore become known at what locations of the explored area deposits of raw materials, minerals or the like are located, a selective extraction or production of the traced raw materials, minerals or the like can be WO 95/12715 PCTNL94/00269 8 carried out. An important aid in this is a vehicle shown in Figure 3. The vehicle 50 comprises a chassis and a superstructure, of which only the superstructure 52 is visible in Figure 3. The chassis is provided with caterpillar tracks 54 for propelling the vehicle 50. The superstructure 52 is rotatable about a vertical axis with respect to the chassis, so that in the orientation shown of the superstructure 52, the vehicle 50 can move both in the longitudinal direction of the superstructure and in an arbitrary other direction, such as a transverse direction.

The superstructure 52 is provided with a winch of which only the drum 56 is shown. On both sides of the vehicle there are pivotable hoist devices 58, by means of which pipes 60 can be moved from and to a store to and from, respectively, the vehicle 50. On the vehicle 50, the pipes can be connected, at their ends, by means of a screw connection, with other pipes 60, in such a way that two pipe strings 62a and 62b are formed. For the purpose of performing the connection operation between the pipes one end thereof can be clamped by a clamping device 64.

After clamping, a pipe 60 can be screwed onto or unscrewed from the pipe string 62a and 62b, respectively, with the aid of a rotary device 66. The rotary devices 66 are mounted on guides 68 in a movable manner and can be displaced across these with the aid of hydraulic cylinders in the directions indicated by double arrows 72.

Although the vehicle 50 advantageously comprises a number of mutually interacting devices, these devices may obviously also be independent, and each may, for example, be mounted on a separate vehicle.

Figure 4 shows those ends of the pipe strings 62a and 62b which face awal from the vehicle 50. At this point, the pipes 60 are coupled, by means of a screw connection, to a pipe 74 which is essentially curved in the form of a semicircle and whose two ends and the central section are mounted in a T-shaped support construction 76 which, by means of a ring 78, is coupled to a cable 80. The curved pipe 74 is provided, in line with pipe string 62a, with a tubular suction head 82 having orifices 84, and is in open WO 95/!2715 PCT/NL94/00269 9 communication therewith. Further, the curved pipe 74 is provided, near the suction head 82, with a number of spray nipples 86, whose spray orifices 88 are in open communication with the interior of the curved pipe 74 and are directed towards the region of the orifices 84 of the suction head 82.

As Figure 5 illustrates, the extraction system according to the invention is similar to the exploration system depicted in Figure i. Although the extraction system can be set up independently of the exploration system, use can advantageously be made of the same heads 8a and 8b, deflection devices 10a and 10b or 10c, cables 12a, 12b and 18, connection element 14, winches 16a and 16b, or 16c and 16d, or 16e and 16f, return idler 20, cable 32, buoy 34 and radio stations 40a and 40b. Specifically for the extraction of raw materials, minerals or the like, the vehicle 50 is positioned on the land 4. As has already been discussed with reference to Figure 3, double pipe strings 62a and 62b can be assembled or disassembled on the vehicle 50. The cable 80 which is linked to the curved pipe 74 is guided around the return idler 20 and wound onto the drum 56 of the vehicle 50. Thus it is possible to move the pipe strings 62a and 62b and thus the suction head 82 in the direction of the arrow 90, by pushing the pipe strings 62a and 62b away from the vehicle with the aid of the cylinders and, if required, additionally applying traction thereto via the cable 80 and the drum 56 by means of the winch of the vehicle 50. A movement of the pipe strings 62a and 62b and the suction head 82 in the opposite direction 92 takes place by paying out the cable 80 and pulling the pipe strings 62a and 62b towards the vehicle 50 with the aid of the cylinders 70. A movement of the pipe strings 62a and 62b in the direction transverse thereto, according to the directions of the double arrow 84, is effected by moving the vehicle 50 in the transverse direction and moving the attachment point 14 in a corresponding direction by suitably driving the winches 16a and 16b.

With reference to Figure 6, the extraction of minerals and raw materials with the aid of the system shown WO 95/12715 PCT/NL94/00269 10 in Figures 3-5 is illustrated. The exploration measurements have already shown at what locations extraction should take place. The suction head 82 can be positioned effectively on the desired location with the aid of the set of radio stations 40a and 40b, the position of the heads 8a and 8b and/or the buoy 34 and a buoy 88 fastened to the support construction 76 with the aid of a cable 86. The pipe string 62b is then coupled to a conduit system 90, incorporated in which there is a high-pressure pump 92 which draws in sea water or river water through an intake 94 and forces it into the pipe string 62b. The flow direction of the water in the pipe sy-tems is indicated by arrows. That end of the pipe string 62a, which faces away from the curved pipe 74 is coupled to a separation installation 96, indicated only schematically. The water forced into the pipe string 62b by the high-pressure pump 92 will thus flow through the curved pipe 74 and the pipe string 62a to the separation installation 96, the water flow at the point of the suction head 82 ensuring such a pressure differential with respect to ambient pressure that material from the bottom on which or in which the suction head 82 is lcated is sucked through the orifices 84 in the suction head and is entrained by the flow of water through the pipe string 62a towards the separation installations 96 for separating the sought raw materials, minerals or the like from the flow of water. Water spraying from the nozzles 86 ensures, during extraction, additional turbulence in the vicinity of the suction head 82 and thus improved extraction, while it is also possible, in this manner, for the suction head 82 to be detached from the bottom if during the extraction it has become embedded therein.

Claims (14)

1. A system for the exploration for or extraction of raw materials, minerals or the like in a soft underwater bottom near land, a first cable being stretched between at least one fixed location situated in the water or on the land, and another fixed location, situated at a distance therefrom in the water or on the land, a second cable being stretched between a point on said first cable and a movable location on the land, which location is situated at a distance from said point on said first cable, which second cable, with the aid of drive means for the second cable, can be moved, under tension, in the longitudinal direction of said second cable, between said point on said first cable and said movable location, said 1"0 first and said second cable being orientated at an angle with respect to one another, exploration means or extraction means being attached to a point fixed on said second cable, characterised in that said first cable with the aid of drive means for the first cable, can be moved, under tension, between said fixed locations, in the longitudinal direction *c of said first cable, said point on said first cable being fixed on said first cable, and means J5 for determining the position of the exploration or extraction means are provided. a

2. A system according to claim 1, characterised in that said drive means for the first S 8 cable includes a first cable drive means at a first fixed location and a second cable drive a means at a second fixed location, said first cable running from said first cable drive means to said second cable drive means.

3. A system according to claim 1, characterised in that said drive means for the first cable includes a first cable drive means at a first fixed location, a deflection device at a second location in the water, and a second cable drive imeans at a third fixed location, said first cable running from said first cable drive means via said deflection device to said second cable drive means. 12

4. A system according to claim 1, characterised in that said drive means for the first cable includes a first cable drive means at a first fixed location, a first deflection device at a second location in the water, a second deflection device at a third location in the water, and a second cable drive means at a fourth fixed location, said first cable running from said first cable drive means via said first deflection device and said second deflection device to said second cable drive means.

A system according to any of claims 1-4, characterised in that said movable location is formed by a vehicle which can be propelled on the land.

6. A system according to claim 5, characterised in that said drive means for the I. 'i second cable are situated on the vehicle,

7. A system according to any of claims 1-6, characterised in that at least one member of the group consisting of the drive means for the first cable, the drive means for the second cable, the first cable drive means, and the second cable drive means includes winches having a rotatable drum onto which one end of the cable is wound. J15

8. A system according to any of claims 1-7 for the exploration for raw materials, minerals or the lik,, characterised in that a return idler is attached to said fixed point of said first cable, said second cable, to which exploration means are attached, running from S said movable location via said return idler back to said movable or to a fixed location.

9. A system according to claim 8, characterised in that said exploration means on a first section of said second cable are stabilized, in the tangential direction with respect to said second cable, by means of one or more arms which extend from said exploration means and whose end is coupled, so as to be movable along said second cable, to a second section of said second cable.

A system according to any of the claims 1-7 for the extraction of raw materials, minerals or the like, characterised in that a return idler is attached to said fixed point of said first cable, said second cable, to which extraction means are attached, running from said movable location or a fixed location on the land via said return idler to said extraction means which extend as far as said movable location or said fixed location.

11. A system according to claim 10, characterised in that said extraction means includes a suction head which has suction orifices and is connected, via a pipe string, to separation means for separating off raw materials, minerals or the like.

12. A system according to claim 11, characterised in that said extraction means "0 includes two essentially parallel pipe strings which extend from said movable location and, at the ends situated in the water, are coupled to one another hydraulically by means of a semicircular pipe connector, with the possibility of forcing a liquid through said pipe strings, by means of a pump, for generating an outward liquid flow in the one pipe string, and a return liquid flow in the other pipe string, said suction head being in open J5 communication with said pipe strings and said pipe connector and extending in the opposite direction to the liquid flow direction therein.

13. A system according to claim 12, characterised in that said extraction means at said movable location includes a vehicle which is provided with coupling, uncoupling and locking means for substantially simultaneously coupling of pipes to each of said two parallel pipe strings, and for substantially simultaneously uncoupling of pipes from each of laid two parallel pipe strings.

14. A system according to claim 13, characterised in that said vehicle is provided with means for pushing against or pulling said pipe strings in the direction of said pipe strings. 1@ RU 0s A 11 A system as substantially hereinbefore described with reference to thle accompanying drawings. DATED THIS 16' DAY OF FEBRUARY

1998. NACAP NEDERLAND F.V. By their Patent Attorneys LORD COMIPANY PERTH, WESTERN AUSTRALIA