UV Basic Advantages
The basic requirements to the extraction technologies are reliability, productivity, efficiency and sustainability in terms of reduction of the environmental damage due to movement of bottom mineralized waters with silt to the surface together with minerals, and as a result of discharge of extraction waste to the near-surface ocean. The Underwater Vehicle (UV) is an advanced, reliable and environmentally friendly apparatus. Exactly these properties constitute its basic advantages. The Vehicle designers had the following task: to create an underwater vehicle, whose design would allow for maximally reliable and environmentally safe use at a great depth thanks to its improved strength, buoyancy and maneuverability. And our team succeeded in solving this task. Below you can learn about the UV technical capabilities.
UV Technical Advantages
The annual operating productivity of the “complex” is 1 mln tons of ferromanganese nodules (FMN) or other minerals. In order to attain the said productivity, subject to the data on deposit density of minerals over the ocean bottom, the UV is capable of handling the bottom areas at the rate of 0.5-0.7 m/sec.
The Vehicle can move with an average practicable speed of the industrial seafloor equipment, and the width of the tool for the collection of minerals is 12 meters. The solution of the task with such technical requirements was a serious challenge for the manufacturers of this complex.
To organize efficient mining operations, it is necessary to use a base dock ship and three bulk carriers with a carrying capacity of at least 35,000 tons, as well as several underwater vehicles with a carrying capacity of 300 tons each. The operations should be planned in such a way that the first bulk carrier will be used during a week as a base for loading and storing one batch of harvested nodules, while the other bulk carrier will deliver the batches to onshore processing plants.
The works system has been planned in such a way that one ore-carrier, within one week, will be used as a nodules loading and storage base for one batch of the collected nodules, while another ore-carrier will deliver the second collected FMNs batch to the processing zone on the continent.
The requirement concerning high reliability of the production complex is not less challenging than the others. The disadvantage of the known vehicles used for the extraction of minerals from the ocean bottom is their insufficient strength, buoyancy and maneuverability that make it impossible to use them effectively at great depth. However, our team has managed to solve this problem through the capability of our Vehicle to operate with zero buoyancy. The UV can pass any obstacles on the ocean bottom by ascending and immersing (as may be necessary), and carries out its work in the most complicated conditions of the World Ocean at the depth of 6,000 meters.
In our Vehicle, the multitiered ballast system is filled with the syntactic material and forms a monolithic unit together with the body. In the course of operation in natural oceanic conditions, this system will demonstrate its high reliability – thanks to its capability of prompt replacement of power units, an emergency ascent unit and a work tool.
Our underwater vehicle is designed for mining with a high shock-wave load: the vehicle operates autonomously, without the base vessel. The base dock ship is equipped with a tank for a quick discharge of the mined minerals.
Another requirement, being not less complicated to fulfill, is trouble-free movement and fault-free operation of the bottom work tool in case of any undetected obstacles on the ocean bottom within the mining zone. This requirement is quite important as the Vehicle will inevitably run into undetected obstacles while collecting the FMNs and other mineral deposits. This problem was also solved by our team who used unique equipment for the Vehicle: while collecting the nodules, its body is moving over the bottom at the height of 3-5 meters. The chains of the work tool with ladles are moving in parallel with the Vehicle body with the help of a stand-alone regulated drive, and, in their hanging position, sliding along the bottom. The specially designed (chain) ladles draw the minerals together with the silt layer; the silt drains though their latticed walls and bottom, while the solid minerals are conveyed to the tank. The chains with ladles slide over the surface of ocean juts: such design allows the tool for the collection of nodules passing the obstacles of almost 1.5-2 meters high, without a need to interrupt mining operations. Besides, the Vehicle is capable of autonomous motion by means of maneuvering devices along the trajectory of the certain pathway. Such system makes it possible to attain the required efficiency and operating productivity of the production complex. Our team, however, has taken into account that on the way of dozens of kilometers in the course of handling the bottom surface at the specified rate, the Vehicle will inevitably and quite often face undetected obstacles.
UV Environmental Advantages
One of the advantages of our underwater vehicle is compliance with the environmental requirements for vehicles operating in the underwater environment, which is so sensitive to any influence.
Our mining technology is based on the use of hydraulic chain buckets, which clamp the nodules but do not crush them, and the elevator system delivers the nodules to the transport tank.
The problem of transporting sludge and bottom waters to the surface is solved as follows: in the storage tank there are openings through which the water flows during the vehicle surfacing. This ensures continuous exchange and flowing of water layers. Undamaged nodules are transported to the surface.
After the water is discharged from the ballast tanks, it goes to the front part of the vehicle, in front of the mining site, thus generating small streams in the seabed area, and removing all living organisms from the nodule-harvesting site. Taking into account the fact that mining operations will be carried out in different areas of the license field and the operations will be shifted by the stream, the nodules will be harvested in a moderate (partial load) mode in different areas. This may help gradual recovery of affected areas after mining operations.
UV Economic Advantages
The economic advantages of the autonomous operation are as follows: during mining, it is necessary to ensure an equal volume of the filled space in the ballast system, which is used for immersion, and for the pumping during the vehicle surfacing. This means that during the surfacing, the autonomous vehicle turns into positive buoyancy and, using its physical properties, autonomously transfers the load from below to the surface (from the depth of 6,000 meters). Thus, the deeper the mineral deposit, the more efficient the mining is (base on a ton of cargo) in comparison with hydraulic lifting through a vertical pipeline.