• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.3
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• pp.652-669
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• 2014

This paper concerns the kinematic characteristics of a coupling device in a deep-seabed mining system. This coupling device connects the buffer system and the flexible pipe. The motion of the buffer system, flexible pipe and mining robot are affected by the coupling device. So the coupling device should be considered as a major factor when this device is designed. Therefore, we find a stable kinematic device, and apply it to the design coupling device through this study. The kinematic characteristics of the coupling device are analyzed by multi-body dynamics simulation method, and finite element method. The dynamic analysis model was built in the commercial software DAFUL. The Fluid Structure Interaction (FSI) method is applied to build the deep-seabed environment. Hydrodynamic force and moment are applied in the dynamic model for the FSI method. The loads and deformation of flexible pipe are estimated for analysis results of the kinematic characteristics.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1213-1220
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• 2015

A deep seabed integrated mining system consists of a mining vessel, a lifting pipe, a buffer station, a flexible pipe, and a mining robot for collecting manganese nodules. Recently, the concept of multiple mining robots was introduced to enhance to mining productivity. In this paper, the subsystem synthesis method was applied to the deep seabed integrated mining system in order to improve the efficiency of system analysis and to facilitate its extension to the system of multiple mining robots. Large deflections of the lifting and flexible pipe were considered by dividing a flexible pipe into several substructures, and applying flexible multibody dynamics to each substructure. Theoretical study has been carried out for the efficiency of the subsystem synthesis method for the integrated mining system, by comparing the arithmetic operational counts of the subsystem synthesis method with those of the conventional method.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.73-78
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• 2004

The deep seabed mining system is generally composed of surface vessel, lifting system, buffer, flexible pipe and miner. The milling system is regarded as a large-scale system in which each subsystem is interconnected to other one. In order to control a large-scale system, a decentralized control approaches have been proposed recently. In this paper, as a basic study on application of decentralized control, firstly, the mining system is simplified modeled, where the lifting system and buffer is regarded as a spherical pendulum and tile flexible pipe is as a two-dimension linear spring. Based on the derived model, the system characteristics and the feasibility of decentralized control are analyzed.

• Ocean and Polar Research
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• v.37 no.2
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• pp.119-125
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• 2015

This paper focuses on the efficient arrangement plan of buoyancy modules, which plan is used to secure the safe operation and structural stability of a marine riser. The marine riser is connected between a vessel and seabed devices. The movement of the vessel and the seabed devices are affected by the motion of the riser. The riser of a deep-seabed integrated mining system exerts a strong influence on the healthy transfer of minerals. So, buoyancy modules must be equipped to compensate for the problem which is the structure stability and the dynamic motion. Installation locations and quantities of the buoyancy modules are determined by real sea experiments. But this is not easy to do because in real sea experimental conditions the cost is expensive as well as being, time-consuming and dangerous. Therefore, the locations and quantities should be determined by numerical simulation. This method is called simulation-based design. The dynamic analysis models of the riser and the buoyancy modules are built into the commercial software of DAFUL.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.315-318
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• 2006

This paper concerns about coupled dynamic analysis of the deep-seabed mining system in launching operation. The dynamic behavior of mining system consisting of lifting pipe, buffer station, flexible conduit and self-propelled miner is simulated in time domain. The launching operation is divided into four critical phases: (1) deployment of miner and flexible conduit, (2) deployment of lifting pipe, flexible conduit and miner, (3) touch-down of miner, (4) final launching. The dynamic responses of sub-systems - miner, flexible conduit, buffer and lifting pipe - are analyzed in each launching phase. According to the changing periods of forced excitation at the top, the dynamic responses of sub-systems are diverse in their characteristics. It has been shown that the total integrated responses of sub-systems are strongly affected by the design parameters. Especially, the principal dimensions of flexible conduit seem to be significant in determining of the global response. Based on the simulation results, safe operation conditions are investigated.

• Ocean and Polar Research
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• v.37 no.1
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• pp.81-90
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• 2015

International Seabed Authority (ISA) is currently developing rules with regard to exploitation of manganese nodules which will be contained in its first regulations governing the exploitation of deep seabed mineral resources. A stakeholder survey was conducted in the early 2014 by ISA with the aim of facilitating participation of interested entities in the development process of the rules. The stakeholders who had replied to the survey included existing contractors, sponsoring States, environmentalists, academics, and nongovernmental organizations. Opinions given by them largely reflect their own interests. This paper aims to clarify the scope of the obligations regarding the environmental protection which may be imposed on contractors under the new regulations for the exploitation of manganese nodules. To do so, it first analyses the express provisions on environmental protection applicable to deep seabed mining included in the Law of the Sea Convention, its agreement on implementation of Part XI, and the regulations on exploration for manganese nodules. Secondly, it categorizes these obligations based on the categories of international obligations suggested by Combacau and Alland. Based on the categorizations this paper concludes that, in addition to the existing duties to protect deep seabed environment within the Law of the Sea Convention system, the following new obligations could be added: conservation of exploitation sites for a limited time after the contract is ceased; taking all necessary measures for rehabilitation of destroyed ecosystems that occurredas a result of mining activities; monitoring exploitation sites for a limited period time after the contract is ceased; observing rules and standards on safety of ships and environmental protection adopted under IMO instruments; regulation on the discharge of mine tailings from the facilities used for exploitation of deep sea minerals. Lastly, this paper attempts to provide ways of reflecting national interests in terms of potential obligations which may be included in the new regulations.

• Journal of Ocean Engineering and Technology
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• v.20 no.3 s.70
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• pp.54-60
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• 2006

For optimal design of a deep-sea ocean mining collector system, based on self-propelled mining vehicle, it is imperative to develop and validate the dynamic model of a tracked vehicle traveling on soft deep seabed. The purpose of this paper is to evaluate the fidelity of the dynamic simulation model by means of response surface methodology. Various statistical techniques related to response surface methodology, such as outlier analysis, detection of interaction effect, analysis of variance, inference of the significance of design variables, and global sensitivity analysis, are examined. To obtain a plausible response surface model, maximum entropy sampling is adopted. From statistical analysis and prediction for dynamic responses of the tracked vehicle, conclusions will be drawn about the accuracy of the dynamic model and the performance of the response surface model.

• Ocean and Polar Research
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• v.36 no.4
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• pp.455-463
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• 2014

This paper presents data from performance tests carried out to assess a manganese nodule crusher. Manganese nodules should be crushed into smaller pieces in order to assure the slurry flow of the lifting system. Both artificial nodules and real manganese nodules are used to evaluate nodule breaking ability of the crusher. The crushing performance of the crusher depends on the flow rate and pressure of the power transmission device. The size of the crushed manganese nodules also depends on the shape of the crushing drum. In this paper, several comparative tests are carried out to evaluate and improve the crushing performance and find the optimal design point of the crusher.

• Ocean and Polar Research
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• v.36 no.4
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• pp.367-371
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• 2014

In early 1990s, the Korean government has launched a deep-sea research program to secure the stable long-term supply of strategic metallic minerals including Cr, Cu and Ni. Through the pioneering surveys, Korea registered $150,000km^2$ of Mn-nodule field in the Clarion-Clipperton area, the NE equatorial Pacific to the international sea-bed authority (ISA) in 1994. Following the ISA exploration code, the final exclusive exploration area of $75,000km^2$ was assigned in 2002, based on results of eight-year researches of chemico-physical properties of nodules, bottom profiles and sediment properties. Since that time, environmental studies, mining technical developments including robot miner and lifting system and establishment of smelting systems were accompanied with the detailed geophysical studies to decipher the priori mining area until 2009. Major points of the recent Korea Mn-nodule program are deployed on a commercial scale until 2015. In order to meet the goals, we developed a 1/5 scaled robot miner compared to commercial one in 2012 and performed a mining test at the water depth of 1,370 m in 2013. In addition, detailed 25,000 scaled mining maps in the priori area, which can provide operation roots of the miner, will be prepared and an environmental-friendly mining strategy will be pursued based on the environmental impact test and environmental monitoring.

• Ocean and Polar Research
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• v.36 no.4
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• pp.383-394
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• 2014

The surface sediments from the manganese nodule exploration area of Korea in the Clarion-Clipperton fracture zone were investigated to understand the resource potential of and emplacement mechanism for rare earth elements (REEs). The sediments are categorized into three lithological units (Unit I, II and III from top to bottom), but into two groups (Unit I/II and Unit III) based on the distribution pattern of REEs. The distribution pattern of REEs in Unit I/II is similar to that of Post-Archean Australian Shale (PAAS), but shows a negative Ce anomaly and enrichment in heavy REEs (HREEs). In Unit III, the HREE enrichment and Ce anomaly is much more remarkable than Unit I/II when normalized to PAAS, which are interpreted as resulting from the absorption of REEs from seawater by Fe oxyhydroxides that were transported along the buoyant plume from remotely-located hydrothermal vents. It is supported by the PAAS-normalized REE pattern of Unit III which is similar to those of seawater and East Pacific Rise sediments. Meanwhile, the PAAS-normalized REE pattern of Unit I/II is explained by the 4:1 mixing of terrestrial eolian sediment and Unit III from each, indicating the much smaller contribution of hydrothermal origin material to Unit I/II. The studied sediments have the potentiality of a low-grade and large tonnage REE resource. However, the mining of REE-bearing sediment needs a large size extra collecting, lifting and treatment system to dress and refine low-grade sediments if the sediment is exploited with manganese nodules. It is economically infeasible to develop low-grade REE sediments at this moment in time because the exploitation of REE-bearing sediments with manganese nodules increase the mining cost.