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By Janine Lahr, Peter E. Halbach

The Manus Spreading Ridge is located within the EEZ of Papua New Guinea and lies in the Manus Basin ENE of the PNG Island and N of the Island New Britain. The divergent backarc spreading system is caused by the subduction of the Solomon plate in the South under the Bismarck plate in the North along the lineament of the New Britain trench. The rate of divergence is relatively high compared to other back arc spreading systems and amounts up to 12 cm/year [3]. Since submarine volcanism and associated hydrothermal circulation as important parts of the oceanic heat transfer system are also dependent on the rate of spreading, hydrothermal fluid venting and respective deposition of polymetallic sulfides can be expected there. In late 1985 first indications for hydrothermal activity were observed on a swell within the central rift valley of the Manus Spreading Centre during a photographic survey of the seafloor by an expedition of the Hawaii Institute of Geophysics with the American RV Moana Wave [1]. Detailed geological investigations including successful sampling were first carried out in June 1990 within the scope of the OLGA II research project (conducted by Prof. Tufar, Marburg) using the German RV Sonne equipped with a deep-sea television sledge and Tvcontrolled grab systems. Simultaneously a research cruise with the Russian RV Akademic Mstivlav Keldysh took place using the manned submersible Mir; the findings of the OLGA II cruise were immediately used for planning and organization of the Mir dives [3]. The massive sulphide samples which we used for our geochemical and mineralogical studies originate from the hydrothermal fields 1 and 2 and are from grab stations of the OLGA II expedition [4].

Sep 24, 2006

By Philomene Verlaan

Analysis of the relationship between environmental parameters and the content of Mn, Ni, Co, Cu, Fe and Zn in ferromanganese crusts permits improved identification of locations to prospect for crusts with commercially valuable concentrations of these metals. In this study we asked whether a statistically significant relationship exists between primary productivity of the overlying surface waters, the concentration of O2 in and depth of the O2 minimum layer on the metal content of non-hydrothermal ferromanganese crusts in the Pacific Ocean between 130o W and 175o E and 0o to 30o S (the study area). To further develop the interpretation of the results of the statistical analysis and to assess in detail the geographical expression of these parameters in terms of metal content in crusts, a geostatistical technique (kriging) was used to generate contoured values for metal content, primary productivity and O2 concentration in and depth of the O2 minimum layer in the study area.

Jan 1, 2001

By Wenbin Ma, Cees van Rhee, Dingena Schott

Since the concept of deep sea mining (DSM) was proposed by J. L. Mero with his book, The Mineral Resources of the Sea, in the 1960s, many research and significant developments have been implemented. However, its commercial mining process still has not yet commenced. One of the most important issues is that a sustainable DSM transport plan is difficult to determine, taking into consideration the DSM technological, economic, and environmental aspects simultaneously. The objective of this paper is to propose a method to determine the sustainable DSM transport plan utilizing a fuzzy analytic network process method, which is a typical multi-criteria decision making method (MCDM). The DSM transport plans evaluating major criteria consist of technological, economic, environmental, and social aspects with both qualitative and quantitative attributes. Different major criteria include several sub-criteria, respectively:  Technological aspect: energy consumption, proven technology, technology reliability, production rate, technology availability;  Economic aspect: gross income, capital cost, operation and maintenance cost, investment recovery period;  Environmental aspect: species disturbance variance, severity of ill effect, turbidity of ocean water, total organic carbon content, sedimentation thickness;  Social aspect: social acceptability, policy support; The weights for all evaluating criteria and sub-criteria are determined through a questionnaire survey interviewing experts at different research fields. All the transport plan candidates are ranked based on a comprehensive index. The conducted research in this paper is meaningful to promote the DSM commercialization process.

Jan 1, 2018

By Mark D. Hannington

Results of the R/V Sonne Cruise (Edison) to the Tabar-Feni Arc from March 11 to April 5, 1994, a joint German-Canadian research cruise aboard the vessel R/V Sonne, undertook detailed mapping of the Tabar-Feni island chain, Papua New Guinea. The Tabar-Feni chain is host to several large porphyry stocks and epithermal gold deposits, including the giant Ladolam gold deposit on the island of Lihir (minimum 19 million oz. Au). The principal objective of the cruise was to map the seafloor in the vicinity of recently active alkaline volcanic islands in the Tabar-Feni chain and to characterize the tectonic setting of large high-level porphyry and epithermal gold deposits in the region. Additional work was carried out on shallow-water hot springs associated with mineralized geothermal systems on the volcanic islands. Complete sets of 1:50,000 scale (20-m contour) maps of the seafloor were produced for each of the four island groups (Feni, Tanga, Lihir, Tabar). The Lihir group was the most active and the most interesting. At least 4 (and probably 6 or 7), previously unknown volcanic cones were discovered within about 10 miles south of Lihir. The volcanoes are clearly very young and appear to have erupted along extensional faults produced by regional plate rotation. This recent volcanic activity appears to reflect recent forearc extension and represents the southward propagation of volcanic activity towards New Ireland. One volcanic cone at 1,490 m water depth is hydrothermally active, with very large areas of diffuse venting (100-200 m across), densely populated by beds of giant clams (probably calyptogena). Other vent-specific fauna are also present, including crabs, snails, sulfide worms, scale worms, limpettes, etc. The clam beds sit on a crust of hydrothermally baked and indurated, sulfidic, hyaloclastite-rich muds. The mineralization consists mainly of fine-grained disseminated pyrite and amorphous Fe-sulfides. A second, much larger cone at a depth of 1,070 m is capped by massive vesicular lavas which are intensely fractured and mineralized. Abundant sulfides and amorphous silica occur in stockwork-like veins which

Jan 1, 1994

By Nobuyuki Okamoto

Ferromanganese crusts on the seamounts in the Pacific Ocean are potential resources of cobalt, nickel, platinum and REEs. Particularly, those of the Republic of Marshall Islands and the Federated States of Micronesia (FSM) waters are believed to be of the highest resources potential area in the Pacific Ocean. The total six cruises using the Japanese Research Vessel Hakurei Maru No. 2 were carried out in the seamounts of the Marshall Islands in 1996, 1998 and 2002, and of the FSM in the 1997, 1998 and 2005 for evaluation of economic potential for cobalt-rich ferromanganese crusts as part of the Japan-SOPAC joint project. During these cruises numerous data such as bathymetric, geological, geophysical and environmental data were obtained. Geophysical exploration with backscatter mapping and side scan sonar, visual imaging using towed TV camera and geological sampling using dredge bucket and/or benthic multi-coring system (BMS) were conducted on these seamounts. In this presentation, we will report the mode of distribution of the crusts and calculated resource estimation based on the results of these geological and geophysical shipboard survey and land-based analyses. Keywords: ferromanganese crusts, Marshall Islands, Micronesia, resource potential

Jan 1, 2011

By Robert G. Ditchburn, Albert Zondervan, Akira Usui, Hiroshi Shibasaki, Hajime Hishida, Ian J. Graham

Earlier reconnaissance geological survey and recent mineral exploration by the Geological Survey of Japan (now part of AIST), Metal Mining Agency of Japan (now part of JOGMEC) have revealed that hydrogenetic ferromanganese crusts are widespread over rock outcrops of the floor of the NW Pacific Ocean, south and east of the Japanese Islands, despite vigorous tectonic activity, such as subduction and backarc spreading. Deposition of ferromanganese oxides has occurred since at least the mid-Paleogene over the Philippine Sea Plate region and nearby.

By Andrea Koschinsky, Luise Heinrich

(for an oral presentation) Activities for preparing future deep-sea mining offer the unique opportunity to study environmental conditions and anticipate adverse environmental impacts prior to the commercialization of the activity. Until know, environmental research has first and foremost focused on understanding direct impacts occurring at the seafloor or in the water column such as the removal of substrate, the suspension of sediment or the creation of particle plumes. Impacts occurring above the sea surface have thus far rarely been considered. The operation of deep-sea mining equipment, as well as of mining and transport vessels will be associated with a considerable energy demand. In the open ocean, this energy will be provided by heavy fuel oil (HFO), which is the cheapest and most common marine fuel. The combustion of HFO will be associated with the release of greenhouse gases and other pollutants. Deep-sea mining will thus directly add to already critical air pollution levels caused by international shipping. To contribute to a holistic assessment of deep-sea mining impacts and to address the previously outlined knowledge gap, we present the methodology to quantify the fuel consumption and associated emissions of a potential typical commercial manganese nodule mining operation in the Clarion-Clipperton Zone (Fig.1). Using the mine set up and energy demand estimates from a study commissioned by the German Federal Ministry of Economic Affairs and Energy supplemented by information from literature, we anticipate emissions of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), nitrous oxide (NO2), nitrogen oxides (NOx), sulfur oxides (SOx), particulate matter and non-methane volatile organic compounds.

Jan 1, 2018

The chemical composition of the nodules varies with the type of manganese minerals and the size and characteristics of their nucleus, but those who have an economic interest have the following composition: Mn 29%, Fe 6% Si 5%, Al 3%, Ni 1.4%, Cu 1.3%, Co 0.25%, Na 1.5%, Ca 1.5%, Mg 0.5%, K 0.5%, Ti 0.2 0.2% and Ba 0.2% (Morgan, 2000; ISA, 2002). The Pacific Rim is an area of abundant occurrence of polymetallic nodules (Glasby et al., 1980; Morgan, 2000). According to these authors, the Pacific sea floor of the Clarion-Clipperton Zone (CCZ) is one of the most interesting areas in regard to the genesis of polymetallic nodules. Their abundance in the ocean floor is very variable, as there are places where they cover more than 70% of the ocean floor. The nodules can be found at any depth, but the highest concentrations are between 4000 and 6000m (Morgan et al., 1993). In studies conducted in the EEZ of the Mexican Pacific are those made within the project "Research on the origin, process and distribution of minerals in the Pacific ocean floor in the Exclusive Economic Zone of Mexico". Within this project Rosales (1989) conducted studies on the origin, process and distribution of polymetallic nodules, finding that a number of processes give origin to nodules, being diagenesis one of the main mechanisms of elements that contribute to the nodules. Besides hydrothermal processes that are carried near the East Pacific Rise at 21° N, inputs are contributing to the nodules metallic elements and sediments, especially in regions close to the dorsal, as a greater influence hydrogenetic processes occurs westward (Rosales and Carranza, 1990). In 1993, after cruise MIMAR II, Carranza and Rosales refer that metals such as Cu, Co, Ni, Sn, Fe, Mg, Pb, Zn and Ba may have a relationship with the East Pacific hydrothermal activity and sea currents carry these metals in solution to the Clarion-Clipperton fracture area, where there are hydrogenic metals sources (Al, Fe and Mn). As result of chemical analysis of Mn, Cu, Ni and Co, polymetallic nodules observed in part of the EEZ of Mexico are possible of potential economic interest (Rosales and Carranza, 1990, 2001; Carranza and Rosales, 2003).

Sep 14, 2011

By Sup Hong

"Lifting riser in deep-seabed mining (DSM) is exposed to acute and chronic stresses of materials, whose yield will result in the most critical loss of total mining system. For freehanging riser (FHR), the axial vibration and local bending of riser may produce acute stresses, in the meanwhile, vortex-induced vibration (VIV) in relative current, friction and collisions of solid particles with inner-wall, and material corrosion in seawater are representative causes of chronic stresses. The chronical stresses bring about fatigue failure or abrupt failure by material loss. Hydraulic lifting is effective and promising for transportation of minerals, however, ecofriendly treatment of operating seawater is an unease hurdle to come over. Sizing of riser section confronts multi-directional problems, i.e. safety of slurry transportation (flow assurance), material safety of riser (wall thickness), seawater treatment on board, etc.A free-standing riser (FSR) might exclude a part of design problems of free-hanging riser and give a way to sustainable mining. FSR stands vertically by means of sub-buoyancy part(s). The top of FSR emerges above sea surface and is connected with mining platform through jumper line (supported by external yoke). Total amount of sub-buoyancy and location(s) have to be carefully determined in viewpoints of dynamics of FSI (fluidstructure interaction) in waves and currents. The concept of FSR gives more freedom for design of multi-functional riser system in view of sustainability of DSM. In DSM, sustainability concept may be focused on eco-friendly treatment of seawater and sediment, and safety of total mining system. For feasibility of FSR, however, installation, maintenance and repair need to be investigated thoroughly in collaboration with industry experts"

Jan 1, 2017

The Brothers hydrothermal system is host to two very contrasting vent fields and to date, is the only known example of this kind for any submarine arc volcano in the world. Firstly, there is the NW caldera field. It is perched on the caldera walls and is up to 1,200 years old, and represents a more ?mature? system dominated by water/rock interactions, though there is also evidence for magmatic contributions to the hydrothermal fluids. It is host to relatively high temperature (~300°C), focused venting of metal-rich fluids. Large Cu- and Zn-rich sulfide chimneys occur at this site, with high concentrations (up to 90 ppm) Au apparent in some chimneys. Vent fluids of the NW caldera site show sub-seafloor phase separation is occurring at this site. Silica concentrations in these vent fluids are consistent with the vent fluid temperatures. Secondly, there is the cone vent field that is much younger, and which sits atop the summits of a main cone (the Upper cone) and an adjacent satellite cone (the Lower cone) that occur inside the caldera, near the southern caldera walls. This field is dominated by S-rich vents with vent fluids more diffuse, lower in temperature (<120°C), very gassy and acidic (to pH 1.9), and relatively metal-poor. Fluids of the cone site have Mg and SO4 concentrations higher than seawater values, indicating these ions have been added to the hydrothermal fluid and are not being depleted via normal water/rock interactions. Variability occurs between the two cone vent fields, with the diffuse discharge observed at the Upper cone volumetrically small and chemically different from the Lower cone. For example, from the vent fluid Mn, Li, Rb, and Cs concentrations, it is apparent that the Lower cone has experienced a lower degree of water/rock interaction (i.e., more reaction) than the Upper cone. Vent fluid pH is higher for Lower cone, consistent with more reaction and neutralization of acidic gases. Fe/Mn is lower at the Lower cone due to decreased Fe solubility at the higher pH. The lowest pH sample (1.9) is from the Upper cone that has 39.4 mmol/kg of SO4, consistent with input of magmatic SO2 and disproportionation to sulfuric acid and S or H2S. Thus, the Upper cone site could be interpreted to have a shorter reaction path and residence time between the point of magmatic degassing and the seafloor venting than the Lower cone site. Isotopic compositions of the NW caldera and cone vent fluids show evidence for magmatic water with negative dD and d180 values, while 3He/4He values show the Brothers hydrothermal system has shifted towards more magmatic conditions over the past several years with both sites affected by magmatic events. Similarly, vent fluid sulfide d34S values and those for sulfide minerals from NE caldera chimneys also indicate disproportionation reactions involving magmatic SO2. Minerals such as chalcopyrite, bornite, chalcocite, covelllite and euhedral grains of hematite occurring in high temperature chimneys from the NW caldera site are consistent with a more oxidizing, magmatic fluid, while bulk sulfide geochemistry data show evidence for a higher temperature suite of elements (e,g., Mo, Co, Se) associated with Cu-rich chimneys. Gold mineralization occurs in these high temperature chimneys and is associated with the most recent deposition of high concentrations of Cu, where d34S values are most negative. Geophysical evidence suggests that the top of a magma chamber occurs ~2.5 km below the caldera floor, beneath the cone site in the SSE quadrant of the volcano. Very low velocities of <1 km-2 are seen in the seismic data between the magma and the seafloor, and are indicative of gas release. Harmonic tremor data provide evidence for a 500 m pipe-like ?conduit? located above the magma chamber (and below the cone), linking it with the overlying hydrothermal system, providing a mechanism for magma-derived metals to enter the hydrothermal system under the cone site. The NW caldera and cone sites are considered to represent stages along a continuum between magmatic-hydrothermal and water/rock-dominated end-members.

Jan 1, 2010

By David M. Holmes-Smith

Many attempts have been made to design and build an AUV that is small, meets the sensing objectives and is cost effective. Many inventors have already designed smaller vehicles but the problem observed is an increased vehicle instability resulting in instrument instability where data gathered is not trustworthy. Additional problems include instrument weight to vehicle weight ratios and the lack of space for power storage and electrical components. The UFOceanic seeks to remedy these concerns by employing a completely different design and propulsion system. Still in the design stage ? now with a mock-up unit for testing, the results are encouraging. We have chosen a very low voltage embedded systems design using multiple PIC processors and fuzzy logic programming. We are designing the craft to rotate for stability and to provide friction reduction to minimize the need for instrument stability compensation and propulsion power. Additionally, we are looking and experimenting with a number of power plant drive systems including flywheels, GNP (plasma), fuel cells and more conventional systems. We of course plan for the UFOceanic to run for months at a time supported by a self-charging system.

Jan 1, 2001

By Robert M. Owen

Recent advances in coring technology and in the development of shipboard and/or in situ geochemical geochemical analysis systems have greatly improved our ability to collect and analyze exploration samples, particularly for marine placer exploration programs. The potential benefit of these improvements cannot be fully realized, however, until we also develop more efficient methods of data reduction and interpretation. Specifically, there is a need to provide prospectors with rapid and useful interpretations of the raw geochemical data so that they can exploit promising results and otherwise optimize the exploration program while the exploration vessel is still at sea. The goal of this project has been to identify and/or develop computer software which is capable of making the necessary data reduction calculations and which can be run on conventional desk-top computers. All work on this project has been supported through a research grant from MMTC-CSD to The University of Michigan. The first stage of this effort involved an evaluation of commercially available (i.e., "off the shelf") software to determine its suitability for use in marine placer exploration applications. Various commercial software packages, each purportedly capable of making different types of statistical and/or mathematical calculations, were tested by evaluating their performance in handling geochemical data sets representative of actual marine placer locations. These data sets include the positions and results of chemical analyses of suites of sediment samples collected from areas of known or suspected marine placers along the Bering Sea coast of Alaska. The evaluation of each commercial program involved a comparison between the results obtained from using the test program

Jan 1, 1991

By David Heydon

The big money is backing both manganese nodules and manganese crusts as the most likely deep ocean mining development by 2010, but seafloor massive sulphides of copper/gold/zinc offer an alternative bet for a start-up by 2010. A study of the ?form guide? or comparison of these resources provides direction on which resources are economic candidates for commercial deep ocean mining development by 2010. This paper covers the commercial and technical issues of exploration, resource definition, drilling/sampling, sea bed mining options, mine plans, environmental issues, legal tenure and capital and operating costs (i.e., profitability) of these two mineral types. Nautilus Minerals has just completed a pre-feasibility engineering study of mining sea floor massive copper/gold/zinc sulphides at 2,000 m depth. The Nautilus study reviewed a range of mining and lifting options, settling on tracked continuous drum cutter miners to produce 2 million tons per annum of high grade ore. Capital costs are shown to be at least 30% lower than a land based copper mine of the same production capacity. Likewise 75% of world?s copper would be produced at a higher operating cost that the proposed seafloor mine. This paper then draws on the Nautilus study for comparison with earlier feasibility studies by others on manganese nodule mining to predict the likely directions in deep ocean mining to 2010.

Jan 1, 2004

By Nii Allotey Odunton

One of the primary responsibilities of the International Seabed Authority?s Secretariat (the Secretariat) is to assess the quantities of metals present in seabed polymetallic nodules in the International Seabed Area under the Authority?s jurisdiction. To carry out this responsibility, the Secretariat periodically undertakes an assessment of the reserved areas in the Clarion-Clipperton region of the northeastern Pacific (CCZ) using the data submitted by the registered Contractors and maintained in the Authority?s POLYDAT database. The results of its most recent assessment demonstrated that the information submitted by the Contractors, though satisfactory for some purposes, does not permit the in situ quantities of metals in these areas to be estimated with a degree of confidence that is comparable to many land-based mineral resource estimates. Our strategy is to divide the work into two distinct but closely related efforts; one to draft a Prospector?s Guide that provides a narrative description of the key geological and oceanographic data that may be related to deposit abundance and metal content, and another that we call the Geological Model, that summarizes and documents the quantitative resource assessments accomplished in the project.

Jan 1, 2005

By Richard Harrison, Frank Lim

"Lifting of slurry from the seabed mining machine to the surface production vessel is a critical element of any deepwater seabed mining system. A Vertical Transport System (VTS) comprises pump(s), riser string, connectors and hang-off assembly as its main components, but it is the pipe material, riser configuration and installation method that often attract the most discussions.This presentation will feature important VTS design work 2H has done over the years for different stakeholders, and highlight the work carried out as a partner to the EU funded Blue Mining Joint Industry Project.The key challenges faced by a deepwater VTS are:??High riser payload??Large deck space for storing riser joints??Long time to deploy and retrieve riser??Uncertain metocean conditions??Vortex induced vibrations??Weld and connector fatigueIncreasing the water depth further sees the longer and increasingly ‘springy’ riser experiencing axial resonance caused by wave induced vessel heave motions being close to the riser resonant period. This can lead to snatch loading and fatigue failure in the riser.The presentation will discuss the above design issues, analysis requirements and provide guidance on pump/riser selection. Solutions to mitigate the resonant response issues will also be proposed.."

Jan 1, 2017

By V. M. Hamza

Analysis of ground and airborne radiometric measurements in the Saquarema region (Rio de Janeiro) provides new insights into the breakdown and transport of mineral aggregates containing monazites, under sub-tropical weathering conditions. The breakdown process, accompanied by loss of low-density clay fractions in weathered materials is considered responsible for the observed patterns in relative enrichment of thorium and uranium along the migration paths of radionuclides. The characteristic features of these patterns provide clues as to the time and distance scales associated with processes of weathering and erosion. It is also possible to determine approximate locations of concentrations of accessory minerals. In this context, we advance the hypothesis that large under-water monazite deposits may be present along the offshore sand banks, in the coastal region of the state of Rio de Janeiro.

Sep 14, 2011

By Brian Parsons

In June of 2013, Odyssey Marine Exploration conducted sea trials of the newly installed SeaBat 7150 full-ocean multibeam sonar system on the M/V Dorado Discovery over the Fierberling Guyot in the northeast Pacific Ocean. Fieberling Guyot is located approximately 990 kilometers west of San Diego, California and it rises abruptly from the deep ocean floor (~4300 meters) to a minimum depth of approximately 438 meters. The SeaBat 7150 operates at two distinct frequencies, 24 kHz (shallow to 3000 meters) and 12 kHz (full-ocean depth greater than 2000 meters). Onboard operational data are managed by a suite of state-of-the-art software. A SQL Server 2012 database provides the highly specific management and visualization tools as ArcGIS 10, Micromine 2013, and Geobank 2013 database. The 7150 is mounted on a gondola one meter lower than on previous system and greatly reduces bubble interference. The 7150 generates 880 beams

Sep 14, 2011

By Usui Akira

Mode of occurrence and compositional variations of iron-manganese deposits from seamounts around the NW Pacific submarine island-arc area are described on the basis of on-site description during the Moana Wave Cruise MW9507 and other Japanese cruises, as well as geochemical and mineralogical analyses and dating on collected samples. Hydrogenetic and hydrothermal iron-manganese crusts occur at more than 80 sites out of 150 dredge hauls within a small area of 200x 200 km in the back arc region. The hydrogenetic crusts may have grown continuously at slow rates, but 2-3 times faster than those from the Central Pacific, associated with depletion of Co, Cu, and Ni contents. The site-maximum thickness of the hydrogenetic deposits trends to increase with the increase of distance from the active volcanic chain or the age of substrate volcanic rocks. Also the observed great local variations in thickness within single sites and on small scales may be resulted from post-depositional geological activity at the seamounts such as calcareous sedimentation, collapse of volcanic body and mass wasting,. On the other hand, the rapid hydrothermal manganese mineralization has occurred in place and time during arc volcanism and rifting and is still in progress at modern active areas. The ninety ICP/ES chemical plus XRD analysis show that these deposits are of distinct composition by origin or topographic provinces, but small-scale variation of the deposits of each origin and micro-scale depth variation are not clear.

Jan 1, 2000

By Timm Schoening, Greinert. Jens, Iason –. Zois Gazis

"Ferromanganese nodules are again of interest because of their high concentrations of Ni, Co, Cu as well as REE. With regards to an operational underwater mining industry, one of the main questions and important requests is to finding a method that can predict the abundance of nodules with high accuracy within reasonable time spans, without many requirements for ground truth data; and all these on an operational scale and ideally automated. In this regard, we present results of a study based on the combination of highresolution multibeam and optical data acquired by an AUV using specific machine learning techniques to reveal a detailed distribution of the Mn-nodules in correlation to the seafloor terrain. The accuracy of the method employed and results gained were validated and approved through comprehensive statistical analysis and by comparison to box-core data.Study AreaOur study area (AUV survey block G77) is located in the Clarion-Clipperton Zone (CCZ) (Eastern Central Pacific Ocean), an area that has been receiving international research and industrial attention for many years already (e.g. McKelvey et al., 1979; Bernhard and Blissenbach, 1988, von Stackelberg and Beiersdorf, 1991, Jeong et al. 1996). Block G77 covers an area of 9.5km2 in a depth between -4478m and -4536m. The area is characterised by gentle slopes 0-5° (0-3° in most of the area and only in the outer parts of the Block slopes can exceed 5°). The seafloor is characterised by moderate to low rugosity, the only exception being a small area in the eastern part, where sub-recent smallscale volcanic activity created 15 cone-shaped morphological features of up to 55m height and 150m width that are clustered in an area of 700 x 380m (Figure 1)."

Jan 1, 2017

By Du Gon Lee

This study presents a model to predict fate of resuspended sediment in the development of deep-sea mineral resources including manganese nodules under Clarion-Clipperton area of the Pacific Ocean. The manganese nodules are expected to be developed near future and major research is undergoing in Korea recently concerning many aspects of the mineral resources development. One aspect is about environmental concern related to the deep-sea development, and a major environmental problem is the resuspended deep-sea sediment. In order to quantitatively analyze the resuspended sediment in the water column during the deep-sea development, particle size distribution (PSD) was considered an important factor in this research. The model developed here includes PSD and coagulation process, as well as sedimentation process. The model is one dimensional in the vertical profile, and was designed to describe the change of particle size distribution in the water column in the given vertical point. Based on the mathematical modeling, a numerical model was developed. Using the model, basic simulation was performed under representative environmental setting of the deep-sea environment. The simulation showed the dynamics of change of particle size distribution for 50 m depth of water column from the deep-sea bed, up to 10 days of simulation time. The simulation results indicate that coagulation seemed an important factor in the fate of resuspended deep-sea sediment. As a result, this research shows that the particle size distribution approach, as well as considering the coagulation process, is needed and may be effectively applied to environmental impact analysis of deep-sea resuspended sediment. Key Word: Deep-sea Mineral Resources, Resuspended Sediment, Environmental Impact, Particle Size Distribution, Coagulation, Modeling and Simulation

Jan 1, 2003