US20150367917A1

US20150367917A1 - Production Support and Storage Vessel

Info

Publication number: US20150367917A1
Application number: US14/651,217
Authority: US
Inventors: Daal Hallam Jaffers; Michael Howitt; Roland Berndt
Original assignee: Nautilus Minerals Pacific Pty Ltd
Current assignee: Nautilus Minerals Pacific Pty Ltd
Priority date: 2012-12-11
Filing date: 2013-11-28
Publication date: 2015-12-24
Also published as: WO2014089599A1; EP2931594A1; JP2016501772A; KR20150086282A; EP2931594A4; KR102214432B1; CN104870305B; JP2019034739A; JP6455842B2; CN104870305A; AU2013359998A1

Abstract

A production support and storage vessel is provided, as well as a method of processing material, such as ore, gathered from the seafloor using such a vessel. The production support and storage vessel has facilities to receive ore from the seafloor, process it, and store the ore in bulk storage silos. Additionally, the production support and storage vessel has a ballast capability and system to ballast the vessel down to a full operational draft. When needed, typically approximately weekly, a transport vessel is moored to the production support and storage vessel and the production support and storage vessel offloads the stored ore using a conveyor system.

Description

FIELD OF THE INVENTION

The invention relates to a production support and storage vessel (PSSV). In particular, the invention relates, but is not limited, to a production support and storage vessel for seafloor mining activities that includes mining and processing equipment and bulk storage and self unloading capabilities for gathered seafloor material.

BACKGROUND TO THE INVENTION

Reference to background art herein is not to be construed as an admission that such art constitutes common general knowledge in Australia or elsewhere.
Seafloor mining operations include gathering of seafloor material and conveying the material to the surface. Typically, seafloor material is gathered and pumped, usually via a riser, to a support vessel on the surface. The support vessel dewaters the seafloor material to an acceptable transportable moisture limit and the seafloor material is then offloaded directly to a transport vessel, such as a mini-bulker or barge. The support vessel on the surface includes a relatively small seafloor ore storage facility that is used to provide a buffer. The buffer capacity typically does not exceed a day's production.
The transport vessel then transports the material to a storage vessel that includes bulk storage for the gathered seafloor material. Alternatively, depending on the proximity of seafloor mining operations to land, the transport vessel can transport the material directly to a land based storage facility. Either way, typically two or three transport vessels need to be employed, more for longer distances, to provide sufficient capacity to transport the gathered seafloor material from the support vessel to the storage vessel or facility. Once sufficient ore has been stored it is loaded onto export vessels that take the ore to market.
The logistics in receiving and transporting the seafloor material therefore requires a significant fleet of vessels. This increases the cost and complexity of transporting gathered seafloor material from the source to market. Furthermore, many mooring operations between the vessels are required, in some cases more than 500 per year. Each mooring operation has a chance of a vessel collision and damage to equipment.
The vast number of mooring operations not only reduces efficiency and increases costs, but mooring operations are considered to be a procedure with a relatively high risk of personal injury occurring and, accordingly, each mooring operation provides a notable workplace health and safety hazard. Each time cargo is handled between vessels there is also an environment contamination risk.

OBJECT OF THE INVENTION

It is an aim of this invention to provide a production support vessel which overcomes or ameliorates one or more of the disadvantages or problems described above, or which at least provides a useful alternative.
Other preferred objects of the present invention will become apparent from the following description.

SUMMARY OF INVENTION

According to an aspect of the invention, there is provided a production support vessel for use on a body of water, the production support vessel comprising:
a seafloor material receiver that receives seafloor material from below the surface of the body of water;
a seafloor material processor that processes seafloor material from the seafloor material receiver;
one or more bulk storage silos that store processed seafloor material from the seafloor material processor;
a loading system configured to distribute processed seafloor material to the bulk storage silos; and
an unloading system configured to offload processed seafloor material from the bulk storage silos to a transport vessel moored alongside the production support vessel.
Preferably, the bulk storage silos occupy a significant portion, preferably a majority portion, of an internal space defined by a hull of the production support vessel. The one or more bulk storage silos preferably have a combined capacity of more than one week's worth of production, preferably more than 20,000 t of ore, even more preferably more than 30,000 t of ore, still more preferably more than 40,000 t of ore.
In a preferred form, four bulk storage silos are provided having a combined capacity of between 40,000 t and 50,000 t, preferably around 45,000 t. The four bulk storage silos are preferably arranged in two pairs of adjacent bulk storage silos. One pair of adjacent bulk storage silos is preferably located toward the aft and another pair of adjacent bulk storage silos is preferably located toward the bow. The bulk storage silos are preferably aligned along a longitudinal axis of the vessel.
The loading system preferably distributes seafloor material, preferably ore, from the seafloor material processor to the one or more bulk storage silos. Preferably the loading system comprises one or more loading conveyors, preferably including one or more scraper or chain conveyors, to distribute the ore to the bulk storage silos. In a preferred form a single loading system is capable of distributing the ore to any of the bulk storage silos. Preferably the loading system also has the ability to bypass the storage silos and deliver ore directly to the transport vessel moored alongside the production support vessel. Preferably the loading conveyors include longitudinal and transverse conveyors to distribute the ore to the bulk storage silos. Preferably the ore is distributed evenly in each bulk storage silo to maximise volume stored and to provide for ship loading ballast and stability considerations.
The unloading system preferably further comprises at least one unloading conveyor system that retrieves material, preferably ore, from the one or more bulk storage silos and unloads it to the transport vessel. Preferably the unloading conveyor system includes at least one scooper, more preferably at least one longitudinal scooper and at least one transverse scooper. The unloading conveyor system also preferably includes a vertical lifter, preferably a bucket elevator, that receives material from the scoopers and a boom conveyor that receives material from the vertical lifter. The boom conveyor is preferably configured to offload the material, typically to a transportation vessel.
In an alternative form the unloading conveyor system includes at least mechanical grab which delivers ore to a hopper that feeds a vertical lifter system. The unloading conveyor system also preferably includes a vertical lifter, preferably a C-conveyor, that receives material from the grab and hopper and a boom conveyor that receives material from the vertical lifter. The boom conveyor is preferably configured to offload the material, typically to a transportation vessel.
In a preferred form, two unloading conveyor systems are provided, a first unloading conveyor system that retrieves ore from a first pair of adjacent bulk storage silos and a second unloading conveyor system that retrieves ore from a second pair of adjacent bulk storage silos. A portion of the first unloading conveyor system is preferably located between each of the bulk storage silos of the first pair of adjacent bulk storage silos, and a portion of the second unloading conveyor system is preferably located between each of the bulk storage silos of the second pair of adjacent bulk storage silos. In a preferred form, each unloading conveyor system includes a longitudinal and transverse scooper in each of the pair of bulk storage silos, a bucket elevator or C-conveyor between each of the pair of bulk storage silos, and a boom conveyor.
The seafloor material receiver preferably includes at least a portion of a riser and the seafloor material processor preferably includes a dewatering plant. The seafloor material processor may comprise a lime storage and dosing system.
The production support vessel preferably further comprises at least one crane. In a preferred form, the production support vessel includes two cranes, a forward crane and an aft crane, that are preferably located on the same side of the vessel.
The cranes preferably have a workable range that covers the majority of the vessel, preferably substantially all of the vessel except for an administration and accommodation portion. The administration and accommodation portion preferably includes a bridge and is preferably located at a forward end of the vessel. A helipad is preferably provided above or adjacent to the administration and accommodation portion. The accommodation portion preferably has accommodation facilities for over 100 people, more preferably over 150 people, even more preferably approximately 180 people.
The vessel preferably further comprises one or more vehicle bays configured to store seafloor vehicles. The seafloor vehicles are preferably seafloor mining vehicles that are unloaded and loaded from the vessel via the vehicle bays. A lift winch and/or hydraulic power unit (HPU) are preferably provided for unloading and loading each seafloor mining vehicle. A vehicle bay may be provided for a seafloor stockpiling bulk cutter, a seafloor auxiliary cutter, and/or a seafloor collecting machine. In a preferred form, a vehicle bay and corresponding winch and HPU are provided for each of a seafloor stockpiling bulk cutter, a seafloor auxiliary cutter, and a seafloor collecting machine.
The vessel preferably further comprises a moon pool that extends vertically through at least a portion of the vessel. The moon pool is preferably an open moon pool that is located in a central portion of the vessel, preferably along a centreline of the vessel. The moon pool is preferably substantially square or rectangular. In a preferred form, the moon pool is a 10 m×10 m square. A derrick is preferably located adjacent the moon pool. In a preferred form, the derrick is located directly above the moon pool.
The vessel preferably further comprises a dynamic positioning system. The dynamic positioning system preferably includes a plurality of thrusters. In a preferred form, the dynamic positioning system includes bow, forward azimuth, and aft azimuth thrusters. The dynamic positioning system is preferably a redundant system preferably equivalent to International Maritime Organisation (IMO) class 2 or even more preferably class 3.
The vessel preferably has a ballast system with sufficient capacity to ballast the vessel to a fully laden position. The ballast is preferably continuously adjustable to enable a substantially constant draft and freeboard during any loading and unloading operations or any launch and recovery operations.
In a preferred form, the vessel has a length between perpendiculars (BP) of between 150 and 250 m, preferably between 180 and 230 m, even more preferably between 200 and 220 m, most preferably around 210 m. In this preferred form the vessel has a breadth of between 20 and 60 m, preferably between 30 and 50 m, even more preferably between 35 and 45 m, and most preferably around 40 m.
According to another aspect of the invention, there is provided a method of processing material gathered from the seafloor, the method comprising the steps of:
gathering seafloor material using one or more seafloor mining vehicles operating under a body of water;
transferring gathered seafloor material to a surface vessel;
processing the gathered seafloor material on the surface vessel;
distributing processed seafloor material to one or more bulk storage silos on the surface vessel; storing the processed seafloor material on the surface vessel in the one or more bulk storage silos; and
conveying processed seafloor material from the one or more bulk storage silos to a transport vessel.
The vessel is preferably the production support vessel as described herein. The step of transferring the gathered seafloor material to the vessel preferably comprises conveying the gathered seafloor material to the vessel using a riser. The step of processing the gathered seafloor material on the vessel preferably includes dewatering the gathered seafloor material, preferably prior to the step of distributing processed seafloor material to the one or more bulk storage silos. Preferably the method further comprises the step of adjusting a ballast to maintain a substantially constant draft and freeboard during any loading and unloading operations or any launch and recovery operations.
The step of storing processed seafloor material on the vessel preferably includes storing at least one full day's worth of production, more preferably at least three day's worth of production, and even more preferably at least five day's worth of production. In a preferred form, the step of storing processed seafloor material on the vessel includes storing at least one week's worth of production which is, preferably, approximately 45,000 t of processed seafloor material.
The method may further comprise the step of transporting the seafloor mining vehicles on the vessel, and lowering the one or more seafloor mining vehicles from the vessel to the seafloor. The method may also further comprise retrieving one or more seafloor mining vehicles from the seafloor and placing them on the vessel. Preferably the seafloor is greater than 500 m below sea level, even more preferably greater than 1,000 m below sea level, even more preferably greater than 2,000 m below sea level, and the steps of lower and retrieving the seafloor mining vehicles comprises lowering and retrieving the vehicles over a distance of at least 500 m, more preferably over a distance of at least 1,000 m, even more preferably over a distance of at least 2,000 m.
Preferably, the step of conveying stored seafloor material from the one or more bulk storage silos to a transport vessel includes conveying the stored seafloor material to the transport vessel whilst at sea. Preferably the seafloor material is conveyed using one or more scoopers, one or more bucket elevators or C-conveyors, and one or more boom conveyors. The step of conveying stored seafloor material preferably comprises retrieving the stored seafloor material from the one or more bulk storage silos using a scooper and placing it in a bucket elevator which transfers the seafloor material to a boom conveyor which offloads the material to the transport vessel.
Further features and advantages of the present invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example only, preferred embodiments of the invention will be described more fully hereinafter with reference to the accompanying figures, wherein:

FIG. 1 is a partially transparent side elevation view of a production support vessel according to an aspect of the invention;

FIG. 2 is a plan view of the production support vessel illustrated in FIG. 1;

FIG. 3 is a plan view of the production support vessel illustrated in FIG. 1 with a transport vessel moored thereto;

FIG. 4 is a plan view showing the deck of the production support vessel illustrated in FIG. 1;

FIG. 5 is a cross sectional view of the production support vessel illustrated in FIG. 1; and

FIG. 6 is a flowchart of an overview of a method according to an aspect of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 5 illustrate a production support vessel 100 having a hull 110 which supports a mining and processing equipment portion 120 and an administration and accommodation portion 180. The vessel 100 has a seafloor material receiver in the form of a riser 200 that is connected to seafloor mining equipment (not shown), which typically operates at depths of 1,000-2,500+ metres below sea level, during seafloor mining operations.
A seafloor material processor in the form of a dewatering plant 300 is provided that processes seafloor material received from the riser 200 and transmits it, once processed, to one of four bulk storage silos 400, 420, 440, and 460. A lime storage and dosing plant 302 is also provided which enables processing of the seafloor material to reduce oxidation of fines ore.
The mining and processing equipment portion 120 of the production support vessel 100 includes two cranes, a forward crane 122 and an aft crane 124. Forward crane 122 and aft crane 124 are both located on the port side of the vessel 100 and have a forward workable range 122′ and an aft workable range 124′ as shown in FIG. 2. The forward and aft workable ranges 122′ and 124′ cover the majority of the vessel 100 except for the administration and accommodation portion 180.
The mining and processing equipment portion 120 of the production support vessel 100 has three vehicle bays for storing seafloor mining vehicles used in the seafloor mining operations, including a stockpiling bulk cutter (SBC) vehicle bay 126, an auxiliary cotter (AC) vehicle bay 128, and a collecting machine (CM) vehicle bay 130 that house an SBC 126′, AC 128′, and CM 130′. The seafloor vehicles, SBC 126′, AC 128′, and CM 130′, are each loaded and unloaded from the production support vessel 100 from their respective vehicle bay 126, 128, and 130.
Adjacent the SBC vehicle bay 126 is an SBC lift winch 132 and SBC hydraulic power unit 134; adjacent the AC vehicle bay 128 is an AC lift winch 136 and AC hydraulic power unit 138; and adjacent the CM vehicle bay 130 is a CM lift winch 140 and CM hydraulic power unit 142. The lift winches 132, 136, and 140 and hydraulic power units 134, 138, and 142 may be utilised in the loading and unloading of the SBC 126′, AC 128′, and CM 130′ vehicles from the vessel 100.
A derrick 144 is provided that extends vertically above a 10 m square moon pool 146 that, as shown in FIG. 1, extends vertically through the hull 110 of the vessel 100. The riser 200 passes through the moon pool 146 to equipment located at or near the seafloor during seafloor mining operations. The moon pool 146 is located generally centrally on the vessel 100, being centred with respect to the vessel's centreline 10. Adjacent the moon pool 146 is a derrick substructure 144′.
The administration and accommodation portion 180 of the production support vessel 100 has a plurality of levels that provide administration and accommodation spaces. In a preferred embodiment, accommodation and facilities for approximately 180 people is provided. A bridge 182 is located on the top level of the administration and accommodation portion 180 with a helipad 184 located above.
Located in the hull portion 110 are the bulk ore storage silos 400, 420, 440, and 460, as well as other services including a power plant 112 that provides power to the vessel 100. The hull portion 110 of the vessel 100 has a large ballast capacity including ballasts 111 configured to keep a substantially constant freeboard, i.e. height of the deck above water level, during seafloor mining operations. The ballast capacity of the vessel 100 is preferably sufficient to ballast to a fully laden condition to enable constant draft and freeboard during loading and unloading operations.
The vessel 100 has a dynamic positioning system that includes a plurality of azimuth thrusters, namely aft azimuth thrusters 114, forward azimuth thrusters 116, and a bow azimuth thruster 118. The dynamic positioning system is a redundant system equivalent to International Maritime Organisation (IMO) class 2 or class 3, which can provide automatic and manual position and heading control, typically within predetermined environmental constraints, with redundancy to allow for component failure except loss of a compartment, e.g. due to fire or flooding.
The production support vessel 100 has a loading system that includes loading conveyors 150, which preferably include transverse chain conveyors, that distribute processed ore from the dewatering plant 300 to the bulk storage silos 400, 420, 440, and 460. The loading conveyors 150 are able to selectively distribute processed ore to any one of the bulk storage silos 400, 420, 440, and 460.
The production support vessel 100 has an unloading system that includes two unloading conveyor systems that each retrieve ore from adjacent pairs of bulk storage silos 400, 420, 440, and 460. An aft unloading conveyor system comprises a longitudinal scooper 402 and a transverse scooper (not shown) located in bulk storage silo 400, a longitudinal scooper 422 and transverse scooper (not shown) located in bulk storage silo 420, a vertical lifter in the form of a bucket elevator 430 located between the aft pair of bulk storage silos 400 and 420, and a boom conveyor 432. A forward unloading conveyor system is similar to the aft unloading conveyor system, and comprises a longitudinal scooper 442 and a transverse scooper (not shown) located in bulk storage silo 440, a longitudinal scooper 462 and transverse scooper (not shown) located in bulk storage silo 460, a vertical lifter in the form of a bucket elevator 450 located between the forward pair of bulk storage silos 440 and 460, and a boom conveyor 452.
The boom conveyors 432 and 452 have respective offload ranges 432′ and 452′ as illustrated in FIGS. 2 and 3. Turning specifically to FIG. 3, a transport vessel 50 is shown moored to the production support vessel 100. The transport vessel 50 has a plurality of cargo holds 52 that are each at least partially covered by the offload ranges 432′ and 452′ of the boom conveyers 432 and 452. In a preferred embodiment, the transport vessel 50 has a total carrying capacity of approximately 30,000 t DWT.
The boom conveyors 432 and 452 have the ability to lift and lower an earth moving machine (not shown) into and out of the cargo holds 52 of vessel 50. The earth moving machine is capable of levelling the material delivered to the cargo holds 52 of vessel 50. This levelling ensures safe shipment of the processed material in the holds 52. The earth moving machine (not shown) is stored on the deck of the vessel 100.
In a preferred embodiment, the production support vessel 100 has a length between perpendiculars (BP) of approximately 210 m, a length overall (OA) of approximately 227 m, and a breadth of approximately 40 m. The dimensions of the production support vessel 100 have been very carefully selected, and the layout of components carefully designed, to provide a single vessel 100 that caters for all surface support aspects of seafloor mining operations.
In use, the production support vessel travels to a desired location carrying the SBC 126′, AC 128′, and CM 130′ vehicles. The vehicles are lowered to the seafloor where they commence seafloor mining operations where they gather seafloor material (step 1000 of FIG. 6). Gathered seafloor material is transferred from the seafloor, typically over 1,000 m below sea level, to the production support vessel 100 (step 1100 of FIG. 6) via riser 200 where it is processed (step 1200 of FIG. 6) by dewatering plant 300 and distributed to bulk storage silos 400, 420, 440, and 460 (step 1300 of FIG. 6). The processed seafloor material is then stored in the bulk storage silos 400, 420, 440, and 460 (step 1400 of FIG. 6) and then subsequently conveyed from the bulk storage silos 400, 420, 440, and 460 to the transport vessel 50 (step 1500 of FIG. 6). As the capacity of the bulk storage silos 400, 420, 440, and 460 is relatively high, ore is transferred to, and stored in, the bulk storage silos 400, 420, 440, and 460 for approximately a week before it is unloaded to the transport vessel 50.
When unloading the ore from the bulk storage silos 400, 420, 440, and 460, the scoopers 402, 422, 442, and 462 scrape ore from the top of the stored ore in the bulk storage silos 400, 420, 440, and 460 and convey the ore to the bucket elevators 430 and 450. The bucket elevators 430 and 450 then convey the ore to the boom conveyors 432 and 452 which then offload the ore to the cargo holds 52 of the transport vessel 50. The transport vessel 50 then transports the ore to a designated location, e.g. to market, and the production support vessel 100 continues receiving, processing, and storing ore from the seafloor mining operations.
Advantageously, the production support vessel 100 can transport and undertake all aspects of seafloor mining operations including transporting and deploying the seafloor mining vehicles, SBC 126′, AC 128′, and CM 130′, receiving and processing gathered seafloor material, and providing bulk storage for the processed seafloor material to allow relatively large transport vessels 50 to subsequently receive the seafloor material and take it directly to market, or the like, without having to accumulate the materials at a further storage location such as a silo ship or on land.
The reduced number of mooring operations compared to a traditional production support vessel significantly increases efficiency while also reducing the risk of collision, personal injury, or environmental contamination occurring. In general, there is also increased safety and efficiency due to less personnel transfers, perishable transfers, and bunkering operations.
The large ballast of the production support vessel 100 reduces the impact between launch and recovery of mining equipment and vessel mooring operations, particularly when offloading significant quantities of stored material to the transport vessel 50. The ballast also allows the vessel 100 to adjust its draft or trim and/or heel to suit operations being performed by or in conjunction with the vessel 100. By enabling the draft and freeboard of the ship to remain constant during loading and unloading operations, and mooring operations, the safety is increased as mooring and lifting operations are simplified and there is a reduced risk of accident due to changes in relative freeboard between the two vessels. The ballast can be adjusted to keep freeboard at a maximum summer load waterline, keeping constant freeboard during all lifting operations including launch and recovery of the mining machines and during subsea lifts to reduce risk and increase safety during these lifts. By keeping a low and constant freeboard the distance from the vessel deck to the water is also minimised which in turn makes the lifts more manageable.
Furthermore, as the production support vessel 100 has a relatively large mass, which can be kept high with the large ballast capacity, the vessel 100 is more stable and has reduced motions and as a result the dynamic positioning system requires less fuel consumption to keep the vessel 100 in location. The increased mass advantageously reduces motion of the vessel which improves crew comfort and safety.
The production support vessel 100 is advantageously designed to be of a sufficient size to contain required equipment for seafloor mining operations and to provide sufficient bulk storage capacity for approximately weekly offloading to a transport vessel 50, without being so large as to require significantly higher power requirements or more than the two cranes 122 and 124 to service the deck. Careful design and arrangement has been conducted to provide an all-in-one vessel while still being efficient and of a manageable size.
There are a number of variations of equipment that can be used to load and unload the vessel with a preferred arrangement being described herein. The described loading and unloading system is preferred as it minimises space occupied by the loading and unloading equipment enabling the volume for storage of ore to be maximised.
References herein to the seafloor, seabed, subsea, or the like are for convenience only and could equally be applied to other bodies of water such as, for example, a lake with a lakebed, etc.
In this specification, adjectives such as first and second, left and right, top and bottom, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, component, or step, but rather could be one or more of that integer, component, or step etc.
The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. The invention is intended to embrace all alternatives, modifications, and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described invention.
In this specification, the terms ‘comprises’, ‘comprising’, ‘includes’, ‘including’, or similar terms are intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.

Claims

1. A production support vessel for use on a body of water, the production support vessel comprising:

a seafloor material receiver that receives seafloor material from below the surface of the body of water;

a seafloor material processor that processes seafloor material from the seafloor material receiver;

one or more bulk storage silos that store processed seafloor material from the seafloor material processor;

a loading system configured to distribute processed seafloor material to the bulk storage silos; and

an unloading system configured to offload processed seafloor material from the bulk storage silos to a transport vessel moored alongside the production support vessel.

2. The production support vessel of claim 1, wherein the bulk storage silos occupy a majority portion of an internal space defined by a hull of the production support vessel.

3. The production support vessel of claim 1, wherein the seafloor material is ore and the one or more bulk storage silos have a combined capacity of more than one week's worth of production.

4. The production support vessel of claim 3, wherein the combined capacity of the bulk storage silos is more than 20,000 t of ore.

5. The production support vessel of claim 1, wherein the one or more bulk storage silos consist of four bulk storage silos.

6. The production support vessel of claim 5, wherein the four bulk storage silos have a combined capacity of between 40,000 t and 50,000 t of ore.

7. The production support vessel of claim 1, wherein the bulk storage silos are aligned along a longitudinal axis of the vessel.

8. The production support vessel of claim 1, wherein a single loading system is provided to distribute the ore to any of a plurality of bulk storage silos.

9. The production support vessel of claim 1, wherein the loading system includes longitudinal and transverse conveyors to distribute the ore to the bulk storage silos.

10. The production support vessel of claim 1, wherein the unloading system includes at least one unloading conveyor system that retrieves stored seafloor material from the one or more bulk storage silos and unloads it to the transport vessel.

11. The production support vessel of claim 10, wherein the unloading conveyor system includes at least one scooper.

12. The production support vessel of claim 10, wherein the unloading system includes a vertical lifter.

13. The production support vessel of claim 12, wherein the vertical lifter is a bucket elevator.

14. The production support vessel of claim 12, wherein the vertical lifter is a C-conveyor.

15. The production support vessel of claim 10, wherein the unloading system includes a boom conveyor configured to offload the material to the transport vessel.

16. The production support vessel of claim 10, wherein two unloading conveyor systems are provided, a first unloading conveyor system that retrieves ore from a first pair of adjacent bulk storage silos and a second unloading conveyor system that retrieves ore from a second pair of adjacent bulk storage silos.

17. The production support vessel of claim 1, wherein the seafloor material receiver includes at least a portion of a riser.

18. The production support vessel of claim 1, wherein the seafloor material processor includes a dewatering plant.

19. The production support vessel of claim 18 wherein conveyors distribute processed ore from the dewatering plant to the bulk storage silos.

20. The production support vessel of claim 1, wherein the seafloor material processor includes a lime storage and dosing system.

21. The production support vessel of claim 1, further comprising one or more vehicle bays configured to store seafloor vehicles.

22. The production support vessel of claim 21, wherein the seafloor vehicles are seafloor mining vehicles that are unloaded and loaded from the vessel via the vehicle bays.

23. The production support vessel of claim 22, wherein a lift winch and hydraulic power unit (HPU) are provided for unloading and loading each seafloor mining vehicle.

24. The production support vessel of claim 1, further comprising a moon pool that extends vertically through at least a portion of the vessel.

25. The production support vessel of claim 24, further comprising a derrick located adjacent the moon pool.

26. The production support vessel of claim 1 further comprising a ballast system with sufficient capacity to ballast the vessel to a fully laden position.

27. The production support vessel of claim 1 further comprising a ballast system that is continuously adjustable to enable a substantially constant freeboard.

28. The production support vessel of claim 27, wherein the ballast system is continuously adjustable to enable a substantially constant draft and freeboard during any loading and unloading operations or any launch and recovery operations.

29. The production support vessel of claim 1 wherein the vessel has a length between perpendiculars (BP) of between 150 and 250 m, and a breadth of between 20 and 60 m.

30. A method of processing material gathered from the seafloor, the method comprising the steps of:

gathering seafloor material using one or more seafloor mining vehicles operating under a body of water;

transferring gathered seafloor material to a surface vessel;

processing the gathered seafloor material on the surface vessel;

distributing processed seafloor material to one or more bulk storage silos on the surface vessel;

storing the processed seafloor material on the surface vessel in the one or more bulk storage silos; and

conveying processed seafloor material from the one or more bulk storage silos to a transport vessel.

31. The method of claim 30 further comprising the step of adjusting a ballast to enable a substantially constant freeboard.

32. The method of claim 31 further comprising the step of adjusting the ballast to enable a substantially constant draft and freeboard during any loading and unloading operations or any launch and recovery operations.

33. The method of claim 30, wherein the step of transferring the gathered seafloor material to the vessel includes conveying the gathered seafloor material to the vessel using a riser.

34. The method of claim 30, wherein the step of processing the gathered seafloor material on the vessel includes dewatering the gathered seafloor material.

35. The method of claim 34, wherein the dewatered gathered seafood material is transferred from a dewatering plant to the one or more bulk storage silos on the surface vessel via a conveyor.

36. The method of claim 30, wherein the step of processing the gathered seafloor material on the vessel includes using a lime storage and dosing plant on the surface vessel to reduce oxidation of the seafloor material.

37. The method of claim 30, further comprising the step of transporting the seafloor mining vehicles on the surface vessel, and lowering the seafloor mining vehicles from the vessel to the seafloor.

38. The method of claim 37, further comprising the step of retrieving one or more seafloor mining vehicles from the seafloor and placing them on the vessel.

39. The method of claim 30, wherein the seafloor is greater than 500 m below sea level.

40. The method of claim 30, wherein the step of conveying stored seafloor material from the one or more bulk storage silos to a transport vessel includes conveying the stored seafloor material to the transport vessel whilst at sea.

41. The method of claim 30, wherein the step of conveying stored seafloor material comprises retrieving the stored seafloor material from the one or more bulk storage silos using a scooper and placing it in a bucket elevator which transfers the seafloor material to a boom conveyor which offloads the material to the transport vessel.

42. The method of claim 30, wherein the surface vessel is the production support vessel of claim 1.