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By Ning Yang, Sup Hong

INTRODUCTION Metal components contained in deep-seabed mineral resources are being highlighted as “energy metals”, which are widely utilized in the entire fields of energy: harvesting and generation, storage and transportation, and saving. Those are mostly trace and rare metals, and rare earth elements as well: manganese, nickel, cobalt, copper, molybdenum, tellurium, selenium, platinum, etc. Toward low carbon society, for global sustainability, the role of metals and minerals is growing up in industries of energy and transportation [1]. In this context, the production and supply of energy metals from deep seafloor have to be approached also based on sustainable development. In deep-seabed mining activity, the sustainability is focused on potential impacts on ecosystems in benthic area and water column. The environmental impacts in deep-seabed mining are caused basically by intervention in benthic zones and transportation of materials. Those are, in particular, removal of benthic habitats, generation and dispersion of sediment plumes, surface transportation of seawater and sediment, tailing from mining vessel, sound and light noises, and chemical leakage, etc. This paper is aiming at fundamental guidance towards sustainable mining of polymetallic nodules.

Jan 1, 2018

By Steven D. Scott

A geologist can be likened to a medical pathologist trying to figure out from faint clues how something had lived and how it died, often long after the event. Present-day seafloor hydrothermalism has empowered geologists/pathologists to dissect a living system, in this case volcanogenic massive sulfides (vms) deposits of copper, zinc, lead, silver and gold. On the other hand, a considerable amount of our understanding of seafloor hydrothermal processes and its products stem from our knowledge, much of it from industry, of these same processes and products that formed ancient ores in oceans as much as 2700 million years ago and are now mined on land.

Aug 24, 2006

By S. E. Boyd

Studies of benthic recolonization following the cessation of dredging in U.K. waters and elsewhere are limited, and are largely confined to experimental circumstances. Investigations of the physical and biological status of licensed areas in the U.K. at various times following cessation of commercial dredging are very limited and so judgments as to the likely progress towards environmental restoration and the time-scales are often based on predictions rather than real data. This study was established to address this deficiency by assessing the status of seabed substrata and associated benthic fauna within and outside areas where dredging had ceased and to conduct follow up sampling to monitor progress towards full recolonization.

Jan 1, 2004

By Makoto Yuasa, Akira Usui, Shipboard Scientists of SIP Cruises, Atsushi Suzuki, Shingo Kato, Kyoko Yamaoka, Akira Nishimura, Kiyo Kisimoto, Katsuhiko Suzuki

"We report here on current topics of our project, based on the results of recent cruises and laboratory analysis, about the diversity of compositions and configurations of the hydrogenetic ferromanganese deposits in several Northwestern Pacific Seamounts. This recent research has discovered important aspects of these deposits regarding the mode of variation with water depth, topography and substrate geology, possible bacterial mediation, temporal variation with age in mineralogy, and major and minor element chemistry. All cruises and analysis have been supported by the facilities and staff of the Japan Agency of Marine-Earth Science and Technology (JAMSTEC), Japan Oil, Gas, and Metal resources Corporation (JOGMEC), Geological Survey of Japan, and Kochi Core Center (KCC) using a remotely operated vehicle (ROV), a monitored rock drilling system, dredges, and manned-submersibles in the NW Pacific seamounts,The results indicate that most of the rock outcrops on the slopes, shoulders, and much of flat tops are covered with maximum 10-cm thick crusts, but the thickness, metal content, and microstructural properties are not always uniform over the seamounts, but variable in space and time. The micro-stratigraphic description of whole-rock samples indicates a history of deposition and sedimentation, which control the diversity in bulk composition and abundance caused by the variable incorporation of iron-manganese precipitates into the deposits during variable environmental conditions. We conclude that hydrogenetic precipitation of iron-manganese oxide has taken place for more than 20 million years at a growth rate about 4-6 mm/my, in water depths below 1000m. The results indicate a fairly continuous and constant metal deposition since the middle Miocene age or older to the present. Our case study of geological sciences at a model seamount within the Japanese EEZ suggests that scientific knowledge is useful and essential in exploring mineral deposits, economic estimation, and designing systems, if supported by well-combined geological and oceanographic and biological research. The distribution map of ferromanganese deposits and geological map will be published soon in 2017 to be issued by the Geological Survey of Japan."

Jan 1, 2017

By J. Robert Woolsey

The Marine Minerals Technology Center (MMTC) was established by Congress in FY 1988 as part of the Mineral Institutes Program, administered by the U.S. Bureau of Mines under the auspices of the Department of the Interior. The primary objective of the MMTC is to encourage the development of selected mineral materials from U.S. seabeds by providing opportunities for appropriate engineering systems research, development, and technology transfer within academic, government, and industrial communities. The center will also provide the leadership and facilities required for the education and training of the nation's scientists and engineers in the field of ocean mineral development. Because of the broad spectrum of study encompassed by the field of ocean mining and mineral resources, the MMTC is organized to include separate divisions for nearshore and deep ocean research. The Continental Shelf Division is administered by The Mississippi Mineral Resources Institute (MMRI) of the School of Engineering at The university of Mississippi. Operational activities will be based at the John C. Stennis Space Center near Bay St. Louis, Mississippi and the Gulf Coast Research Laboratory, Ocean Springs,

Jan 1, 1988

By John W. Padan

What is known about manganese nodules and their potential commercial recovery is outlined in terms of economics, legal rights, environmental impacts, and mineral genesis. As a result of 20 years of accomplishments it is clear that nodules comprise a real resource, and that they can be collected in water depths up to 5000 m, for brief periods, and raised to a surface vessel at rates of production appropriate for scale model systems. Based upon information in the public domain at present there is more confidence in the nature and magnitude of the resource than in the ability to recover nodules commercially. A review of the literature suggests that the metallurgical processing of manganese nodules is technically feasible and that the associated costs are well predictable. What is less clear is the market outlook for the products. All "overlapping claim" conflicts have been resolved. Therefore, parties with a historic interest in nodule mining appear now to have the right to mine in the future, assuming they properly complete whatever exploration license obligations they may have.

Jan 1, 1989

By Lu Jun

Up to now, much data on marine minerals, as well as on marine geochemistry, have been accumulated. Modem computer databases provide optimum flexibility and power for manipulating these data. The best worldwide marine mineral database is currently the Marine Minerals Bibliography and Geochemical Data Base created by Carla Moore et al. at the National Geophysical Data Center in the United States. In fact, in the course of studying marine minerals and geochemistry we may collect not only digital-character type data but also graph and image (black-white, grey and color image) data types. For instance, correlation diagram between chemical compositions of minerals, spectroscopic graphs, (e.g. infrared spectra, Mossbauer spectra, etc.), grey or color images from both optical and electron micro- scopes (scanning or transmission electron microscopes) as well as seabed photographs. Charles L. Morgan et al. (1993) reported that 10,000 photographs and some video images of the seabed in the Clarion-Clipperton region of the northeastern tropical Pacific have been collected by the Ocean Minerals Company. If both graphic and analytical information were stored in a database, it would be very useful and convenient to marine geologists. This system would not only be able to search for all the data based on one parameter, but also for both size and composition distributions. If possible, geostatistical methods could be combined with fractal dimensional methods. Of course, this would require enormous efforts. Before multimedia technology emerged, it was very difficult to create image databases. The emergence of large-capacity compact discs, high-speed central processing units, and high-speed digital signal processing techniques makes it possible to establish multimedia database management systems (DBMS), image-text DBMS, that involves graphs, text, images, and sound. In order to store image fields in a DBMS, we have to take into account two problems: (1) image access format and (2) image compression code standard.

Jan 1, 1994

By V. Soloviev

The world?s data available on near sea-bottom gas-hydrate accumulation and deep-water fluid-discharge areas are presented in this paper. Gas-hydrate accumulation associated with fluid discharge (mud volcanoes, gas seeps, gas-saturated water seeps) is characterized by the following. First, the largest hydrate accumulations in sediments are located at shallow subbottom depths and have well-defined limits, especially in the upper subbottom part. Second, gas-hydrate formation in fluid-discharge areas is a present-day process, with the global occurrence of deep-water fluid-discharge areas numbering up to about ten thousand, and with all the seep areas being favorable for the formation of near-sea-bottom gas-hydrate accumulation. Third and principal, gas resources in the hydrates can be considered as renewable. Estimates of possible gas volume in single accumulations of hydrates and the global budget, as well as possible methods of gas utilization from such gas-hydrate accumulations are discussed in the paper.

Jan 1, 2005

By Tae-kyeong Yeu

KIOST has developed the pilot mining robot, named MineRo ?? from early-2011 to mid- 2012. The robot consists of two unit-modules having an identical mechanical structure and hydraulic system. One unit-module has two track systems, two pick-up devices, two crushers, one lifting pump and one thruster. The pick-up device is fitted on the frame of the track device. All actuators are driven hydraulically, which are manipulated by valves and the controllers. Each unit-module is equipped with one dual HPU of 250kW / 4,000V. PWM-16 (INNOVA AS) as hydraulic valve controller is adopted, which outputs PWM signals of 16 channels and can be used under pressure in oil-filled box. To measure angular velocity or displacement of hydraulic actuator, turbine-type flow-meters are adopted. The flow-meter has RF (Radio Frequency) type pulse detector, which extends the flow range by eliminating drag on the rotor. Two track motors, two crusher motors, lifting pump, one thruster can be controlled their velocities through feedback of the measured flow-rates. As well as the flow-rates, the states of the hydraulic system such as hydraulic pressures, temperatures, leakages are measured through a self-developed flow-pressure canister. In that canister, multi-channel amplifier boards are installed, through which the vast amount of data is acquired and transmitted to the main controller using serial communication.

Sep 14, 2011

By Rolf B. Pedersen, Ingunn H. Thorseth, Håkon Dahle, Ingeborg E. Øklandm, Linn M. B. Olsen

Weathering of sulfides and the generation of acid mine drainage (AMD) is a well- known environmental issue in on-land mining. The process can release potentially toxic compounds and heavy metals to the environment and is highly influenced by microbial activity. However, the weathering of sulfides in deep-sea environments is not well studied. In 2014 we therefore deployed two titanium incubators filled with freshly ground pyrite grains into an inactive part of the hydrothermal sulfide mound of Loki´s Castle vent field, aiming to study the in-situ seafloor weathering of the freshly exposed sulfides. Each incubator had five chambers placed in a depth profile, where the upper chamber was exposed to the bottom seawater. After one year of exposure, one incubator was collected and analyzed for weathering features and microbial colonization and community composition. In addition, one sediment core (25 cm deep) was collected from the sulfide mound in close vicinity to the incubators, and another core (45 cm deep) was collected from the (hemi)pelagic sediment just outside the sulfide mound. The cores were analyzed for geochemical composition of the solid material and porewater, and the microbial community composition aiming to define the redox zoning and dominating geomicrobiological processes in the natural deposits, and to unravel how these processes influence the mobility of heavy metals during sulfide weathering. Scanning electron microscopy (SEM) revealed development of Fe-oxyhydroxide weathering rims on the pyrite grains in the incubator chambers. Spalling of the rims on the most weathered grains, exposing fresh pyrite surfaces to oxidation, was commonly observed. The SEM investigation also revealed a positive correlation between weathering degree and microbial community density. Preliminary results from the microbial community analysis show a high relative abundance of putative sulfide oxidizers, suggesting that the community is governing the degradation of pyrite.

Jan 1, 2018

By Akira Usui, Sayuri Kubo, Satoshi Tokeshi, Shingo Kato, Katsuhiko Suzuki, Teruhiko Kashiwabara

"INTRODUCTIONFerromanganese (Fe-Mn) crusts are a kind of marine chemical sediment composed of Fe and Mn oxy-hydroxides as well as small amounts of clastic sediments, which are ubiquitously found on the surface of slopes of seamounts and oceanic plateaus at depths from 900 to 5500 meters below sea level (mbsl). Fe-Mn crusts contain extremely high concentrations of useful minor metals such as Co, Ni, Te, REEs, and thus are expected as submarine mineral resources. Also, Fe-Mn crusts record the change of chemical compositions of seawater during last several tens million years, which allow us to obtain clues to clarify the paleoenvironmental conditions at the time of its deposition. However, occurrence, chemical compositions, microbial community and growth patterns of ferromanganese crusts are yet fully understood. Hence, a comprehensive study on the genesis of ferromanganese crusts, such as growth rates and enrichment processes of elements, is required to better understand their resource potential as well as their applications to paleoceanographic study.Based on the resource potential of ferro-manganese crust, the project entitled “Next- Generation Technology for Ocean Resources Exploration” was launched as one of the governmental projects to develop the exploration technology based on the scientific research on the submarine resources such as hydrothermal deposits (e.g., a poster by Kawada et al.), ferro-manganese crusts. We have made several research cruise to seamounts in the north-western Pacific such as Takuyo-Daigo and Takuyo-Daisan seamounts (Fig. 1) ."

Jan 1, 2017

By William C. Hirt

Column flotation is a promising technique for processing as-mined, cobalt-rich, ferromanganese crust to separate the valuable crust component from barren substrate-rock, either aboard ship or within the water column. Column flotation testing was carried out in a seawater medium using samples obtained from the U.S. Exclusive Economic Zone (EEZ) in the mid-Pacific Ocean near Johnston Atoll. The collector reagent was a mixture of diesel fuel, fatty acid, and sulfonate previously developed at the U.S. Bureau of Mines for crust flotation using conventional flotation cells. Results are dependent upon particle size and reagent dosage, especially *as these factors affect froth volume and stability. Column flotation results are compared with previous studies in conventional cells. An overview of how column flotation might be applied in an offshore mining and processing system is given.

Jan 1, 1992

By Samantha Whisman, James R. Hein

Hydrothermal marine manganese-oxide deposits (HMMD) are cemented and variously replaced volcaniclastic and biogenic sediments that were mineralized by distal, low- temperature, hydrothermal fluids. HMMD predominantly form below the seabed as sediment-hosted statabound deposits but can also form on the seabed. These deposits form at oceanic and back-arc basin spreading centers, volcanic arcs, and mid-place hotspot volcanoes. HMMD have traditionally not been considered to have an economic potential because they were considered to be devoid of economically valuable critical elements. This contrasts with their non-hydrothermal counterparts, ferromanganese crusts and nodules, which are enriched in many critical elements. However, manganese is now one of the critical metals and HMMD have the highest manganese contents (up to 55% Mn, so- called battery-grade Mn) of all the types of deep-ocean mineral deposits. There is a growing demand for this critical metal and an upward trend exists in the price of manganese on the global market. Also, other critical elements can occur in high concentrations in some HMMD and their economic potential has not been considered, especially for lithium (up to 0.17%) and molybdenum (up to 0.24%), but also vanadium (to 820 ppm), chromium (to 346 ppm), and nickel (to 0.45%), among others. Which of these critical elements are enriched and their concentrations depend on the types of rocks leached at depth by the hydrothermal fluids, the composition of hydrothermal minerals precipitated in the higher temperature parts of the circulation system, and the types of sediments mineralized by the manganese oxides. For example, mineralization of a carbonate sediment resulted in the highest lithium contents, whereas leaching of ultramafic rocks at depth as a rule results in the highest chromium and nickel contents in the HMMD. These deposits are known to be widespread, especially in volcanic arcs, but their lateral and vertical extents and consequently size, tonnage, and grade have not been determined. Most samples of hydrothermal deposits have been collected by dredging and therefore the in situ relationships often are not known. One sample from the Mariana volcanic arc, west Pacific, was collected by ROV at 1274 m water depth from a layered outcrop 6.6 m thick that may be a sequence of pervasively mineralized volcaniclastic layers and offers the first clue as to the potential vertical extent that these deposits may attain. However, only the top ~0.4 m-thick layer was sampled, so it is not known whether the mineralization extents throughout the outcrop. Although large manganese deposits of various origins occur on the continents, they consist of manganese carbonates, silicates, or complex mixtures of manganese minerals. In contrast, marine hydrothermal HMMD exhibit relatively simple mineralogy that would make processing of this potential ore much simpler.

Jan 1, 2018

By S. Rajendran

Much advance has been made in offshore hydrocarbon exploration and exploitation in India. But the same amount of success could not be achieved in the case of other offshore minerals which are amenable for mining. However, employing present technology, there should not be any difficulty in successful exploitation with minimum environmental hazards. A demonstration is provided by considering the conditions prevailing in the Kerala offshore (southwest coast of India) scenario of monazite, ilmenite, phosphatic mud and calcareous deposits. Mud banks are unique phenomenon of the Kerala coast during monsoon season. Acting as barriers to waves, mud banks protect portions of the beaches from being eroded and trap sediments from either side facilitating growth of adjacent beach. The easy minable possibilities of the phosphatic mud during non-monsoon season with less pollution hazards and dumping back the waste material after processing for phosphate at the breaker zones to reduce the erosional effects on the coast make the exploitation economic and ecofriendly unlike the benefication of the lowgrade phosphate ores on land on a comparatively larger area and subsequent crushing, transport and resulting pollution.

Jan 1, 1993

By Cheong-Kee Park

Paleomagnetic properties of sediment cores were examined to reconstruct paleodepositional conditions in the Korea Deep Ocean Study (KODOS) manganese nodule area, located in the northeastern equatorial Pacific. The KODOS sediments studied have a stable remanent magnetization with both normal and reversed polarities, which are well correlated with the geomagnetic polarity timescale for the late Pliocene and Pleistocene. Average sedimentation rates were 1.56 and 0.88 mm/kiloyear for the Pleistocene and late Pliocene, respectively. Clay mineralogy and scanning electron microscope analyses of the sediments indicate that terrestrial material was transported to the deep-sea floor during these times. The variations of sedimentation rates with age may be explained by the onset of the northern hemisphere glaciation and subsequent climatic deterioration during the Pliocene and Pleistocene. For the Pleistocene, an increasing sedimentation rate implies that input of terrestrial materials was high, and also a high input of biogenic materials was detected as a result of increased primary production in the surface water. The down-core variations in paleomagnetic and rock-magnetic properties of the KODOS sediments were affected by dissolution processes in an oxic depositional regime. As shown by magnetic intensity and hysteresis parameters, the high natural remanent magnetization (NRM) stability in the upper, yellowish brown layers indicates that the magnetic carrier was in pseudo-single domain states. In the lower, dark brown sediments, only coarse magnetic grains survived dissolution and the NRM was carried by more abundant, multi-domain grains of low magnetic stability. The down-core variation of magnetic properties suggests that the KODOS sediments were subjected to dissolution processes resulting in a loss of the more stable components of the magnetic fraction with increasing core depth.

Jan 1, 2004

By Jonguk Kim

The North Fiji Basin (NFB) is a mature intraoceanic back arc basin with an age of ~12 Ma. Recent volcanism and spreading activity are focused along the Central Spreading Ridge (CSR), A ridge segment more than 800 km long, composed of four main segments, the N160°, N15°, north-south (N-S), and southernmost segments from north to south. The dominant volcanic rock in the entire central spreading ridge is normal mid-ocean ridge basalt (N-MORB), very similar to those emplaced along mid-oceanic ridges. Conversely, influence of an oceanic island basalt (OIB) source increases northward from 18°20'S. Several basalts which show a significant subduction-related component are also observed in the southern part of the NFB. Hydrothermal activity along the spreading centers of the North Fiji Basin was investigated by several previous works, especially by the STARMER project in 1989 and 1991. Both extinct and active hydrothermal vents are found on the N15° and N-S segments. In contrast, only traces of hydrothermal activity have been found on the N160° segment. Although high temperature activity and related massive sulfide deposit on the N15° segment was further investigated by several follow-up studies, no systematic survey for other hydrothermal sites was conducted after their discovery. In 2012 and 2013, KIOST performed two hydrothermal expeditions aboard the R/V Onnuri in the three targeted areas of hydrothermal activity along the CSR of North Fiji Basin. All targeted areas include sites for hydrothermal activity reported in previous works. Occurrence and distribution of hydrothermal plume were investigated by combined

Sep 14, 2011

By Cheng Xiangzhou

The China's Pioneer area includes two parts. The topography in the western part is very different from that in the eastern one. The distribution of the manganese nodules in these two regions differs correspondingly China Ocean Mineral Resources Research and Development Association (COMRA) will take appropriate measures so that the next development will be adapted to the features of its potential minable area.

Jan 1, 1996

By B. J. Bluck

Diamond mega-placers, in order to rank amongst the primary diamond deposits, are defined as => 70 m carats at =>95% gem quality. There is only one mega-placer known and that is found along the coast of southwestern Africa fringing the Kaapvaal craton. Placers are classified as residual when they are left on the craton, transient when being eroded into the exit drainage and terminal. Terminal placers, in being the final depositories of diamonds off the craton, have the greatest probability of being a mega-placer and such is the case in the placer deposits near the Orange River mouth, southwestern Africa. There are four main groups of conditions leading to the development of a mega-placer: the craton, the drainage, the nature of the environment at the terminus and the timing. The craton, in its role as the producer of diamonds is significant in respect to its size, diamond-fertility, the degree to which diamonds from successive kimberlite intrusions have been retained there and their availability to the final drainage yielding the mega-placer. Cratons in being buoyant have a tendency to leak diamonds into surrounding basins but in being incompressible often have orogens converge onto them resulting in lost sediment being returned as foreland basin fills. In order to concentrate a bulk of diamonds the drainage basin has to be large with a high proportion of it on the craton. The drainage yielding the mega-placer should ideally not have been preceded by older drainage and other systems that may have robbed the craton of earlier diamonds. The exits of diamonds from the craton need to be few in order to focus on their supply and the drainage network needs to be efficient in order to remove the maximum volume of diamonds off the craton. This efficiency and the focused termination is best achieved by the rejuvenation of a pre-existing drainage network. The drainage should be young enough to yield host sediments friable enough to allow brittle diamonds to be recovered from them.

Jan 1, 2004

By Tap Pryor

A very small nation with large seabed resources requires a strategy. The simplest approach is to duplicate every step taken by the United Nations (UN), in its own leasing programme. In addition, the smaller nations must sell itself and its competitive offering. It is one thing just to await applicants and/ or tenders, another to work to make the leasing seem like a very good idea. This cap be achieved through publications, correspondence, meetings (such as the Underwater Mining Institute, but especially through pro-active planning, seeking the ideal technologies in both harvesting and processing. The ideal would be some combination that could begin quickly and on a small scale. It must be within the UN environmental guidelines. To meet the "quick and small criteria," simple harvesting and physical processing methods must be given the highest priority. Once these are satisfied, then marketing studies can be completed. There is, of course, a market for every element but only careful engineering and cost analysis will determine accessibility. What is required is a stepwise approach, gaining greater and greater credibility at each step. In fact, much planning can be done for very low cost. In the Cook Islands, the first crucial step was the East-West Center publication which pulled together all facts in one volume and which found the local resource to be richer in significant ways than Clarion-Clipperton. Most seem to believe that it could be many years before full production is possible, but this has been conventional wisdom for so long that it has taken on the suspicious aura of myth. Is it real? Have all possible recent technologies such as robotics and physical processing been taken into account? Either way, it is essential that a comprehensive approach be taken so that all factors from resource to market are considered as inter-related until a single business plan emerges. When that is in hand and when its profitability and risk levels are found to be credible, adequate investment funds are available.

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