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By H. Shimoda, K. Tamaki, K. Iizasa, M. Watanabe, K. Okamura

Modern Kuroko-type deposits occur in submarine calderas of island-arc fronts and back-arc rifts in Japan. They occur primarily on or adjacent to caldera boundary faults. Hydrothermal sulfides in the Myojinsho submarine caldera are one of Kuroko-type deposits, but their occurrence is different from other deposits found within the area 200 km2 around the Quaternary volcanic front of Izu-Ogasawara arc.

Aug 24, 2006

By Kokichi Iizasa

Modern Kuroko-type deposits have been much reported in submarine calderas and cauldrons in the EEZ of Japan since 1988. Some of them have been found based on heavy mineral analysis of sediments in which sulfide particles may be derived from hydrothermal sources in the ambient areas. From the end of August to early September 2007, in the middle Izu-Ogasawara arc south of Tokyo, ROV expeditions were carried out in submarine calderas in order to examine mineralogical features between intact heavy particles spouting out from sulfide chimneys and heavy minerals such as sulfides in sediments around sulfide mounds in Kuroko-type deposits, and to find more newly formed hydrothermal sulfide fields in those areas. Some preliminary results from the ROV expeditions are reported here.

Oct 15, 2007

By Stanley R. Riggs

Phosphate deposits on the southeastern U.S. coastal plain have long been the major force in world phosphate markets. World markets continue to grow, but the role of U.S. resources is rapidly declining. This situation results from a complex interaction of economic, political, and environmental factors. Causes for this ongoing erosion of the U. S. market include 1) escalating costs, 2) changes in land-use patterns, 3) environmental pressures oh conventional mining techniques; 4) exhaustion of shallow, high-grade resources in Florida, and 5) increased, low-cost production in other countries throughout the world. In fact, some agencies and commodity personnel predict that the U.S. will become a net phosphate importer early in the next century. If this projection is correct, the U.S. industry must look towards major changes in the near future in order to continue to compete in the world market. One possible change includes development and application of unconventional mining techniques to cheaply recover vast 'new' potential resources in areas with lower land-use pressures. These 'new' resources include 1) deep phosphorites within major sediment basins of the southeastern coastal plain and 2) subsurface phosphorites on the continental shelf and within the U.S. EEZ. These latter resources include extensive deposits in Onslow Bay, N.C.; broad regions offshore of Savannah, Ga. and Cape Canaveral, Fla.; and the central portion of the west Florida shelf. Little research and exploration has been

Jan 1, 1988

By Amy Gartman

The interactions between hydrothermal fluids and seawater result in minerals that range in size from nano- to macro-scale and constrain mineral emplacement, whether in hydrothermal chimneys or metalliferous sediments. Although broad similarities exist, and sulfides are the most important component of seafloor massive sulfide deposits, the specific mineralogy, size and therefore reactivity of particles emitted varies between hydrothermal sites in the global ocean, and even at different sites within the same vent field. The oxidation of sulfide minerals results in one of the major impacts of terrestrial mining of volcanogenic massive sulfides as it creates acid mine drainage. At marine hydrothermal vents, the chimneys themselves, as well as the ‘black smoke’ begin to oxidize as soon as they are in contact with ocean water; the breaking of sulfide minerals during marine mining will expose further surface area to seawater and oxidation. Although the cold temperatures and circum- neutral pH result in oxidation proceeding less rapidly than in many terrestrial systems, there is limited data on the kinetics of sulfide oxidation in seawater. Here, the oxidation of sulfide minerals in seawater and the implications for marine mining will be discussed, with an emphasis on nano-ZnS and sphalerite, including reaction kinetics, processes, and oxidation products.

Jan 1, 2018

By R. P. Das

Processing of polymetallic nodules poses several challenges to metallurgists. These include the presence of at least 80 elements in nodule, presence of Ni, Cu, Co in no specific mineral form, presence of almost 30 % seawater in freshly collected nodule, and collection of slime along with the nodule. For almost 40 years, several research groups from all over the world are engaged in developing an appropriate process to extract metals from poly-metallic nodule. These processes have been tested in scales varying from few grams to several hundred kilograms (Das, 2001; Jandova, 2001). All these tests helped in defining various parameters for processing, and simultaneously brought out some of the inherent problems of processing nodules. Based on the information and the experience of all these studies, in recent years, most research groups, involved in developing metallurgical processes for nodule, are focusing their efforts in two or three alternative directions. While attempts are made to overcome some of the major challenges in processing, several new ones crop up. The difficulties are further compounded because no mining system is operating to generate some of the data required for process development. The aim of this presentation is to highlight the research efforts, and to identify areas requiring special attention of a process developer.

Jan 1, 2003

By Alan Foley

The Portable Remote Operated Drill was developed in Sydney, Australia in the 1990’s. The device is a platform for many in-situ seabed sampling and coring tasks. The range of tools developed for use in PROD’s magazine now includes gas detectors, vane testers, penetrometers and corers. This paper presents aspects of the soils testing undertaken in deepwater since 2005, focusing on testing of methane hydrates and reefal accumulations. The varied selection of tools carried in PROD’s magazines allow the unit to perform several functions from the seafloor in one deployment.

Sep 24, 2006

By Tony van der Steen

Subsea mining system are designed for the following, principally different, tasks: Dreding - The destruction and removal of seabed sediments overlaying the bedrock. Cleaning - The competence of the system to systematically remove the deposits from an undulating hard bedrock with irregular pulleys, channels and fissures. Factors that influence the choice of dredging equipment for a specific project are project requirements such as environmental conditions, location and water depth. However, the most important selection criteria are soil conditions. As a consequence, possible dredging systems, must be evaluated for the following, principally different, characteristics: Dredging proficiency - The destruction of the strata by the equipment. System stability - The capability of the soil to support the subsea equipment The above parameters are determined by the strength characteristics and the bearing capacitv_ of the soil. The author describes the processes involved in excavating the subsea deposits and (transporting the gathered soil as a water-soil mixture to the surface using different excavation and transport methods.

Jan 1, 1998

By Robert G. Paul

President Reagan's Exclusive Economic Zone (EEZ) Proclamation of March 10, 1983, extended United States ocean jurisdiction 200 nautical miles offshore our coastal states and territories. The accompanying policy statement noted that this action was a result of recently discovered deposits of polymetallic sulfides and cobalt-rich manganese crusts, which could be a major source of minerals important to the U.S. economy and security. Within these 3 billion acres of exclusive economic jurisdiction, the United States has sovereign rights to explore, develop, conserve, and manage the mineral and other natural resources of the seabed. The President has directed the Department of the Interior (DOI) to encourage exploration and production of minerals from this area. The DOI, through the Minerals Managment Service (MMS), is responding to this presidential directive by developing a leasing program for nonenergy minerals in the EEZ. The authority to develop this leasing program is the Outer Continental Shelf Lands Act of 1953, as amended in 1978, which authorizes the Secretary of the Interior to grant leases for oil, gas, sulfur, and other mineral resources on the Outer Continental Shelf (OCS). The Solicitor of D01 has determined that the definition of the OCS for legal purposes extends at least 200 nautical miles offshore of our coastal states to the EEZ boundary. Section 8 (k) of the Act allows the Secretary to lease minerals, other than oil, gas, and sulfur, on the basis of competitive bonus bidding and under such terms and conditions as he may prescribe at the time of offering the area for lease.

Jan 1, 1985

By Ki-Hyune Kim

The Korea Ocean Research and Development Institute conducted its first exploration for deepsea mineral resources in 1983, and began a systematic deepsea prospecting in 1989 among Micronesian islands and in central and eastern parts of Carion-Clipperton fracture zones of eastern Pacific. With the arrival of R/V Onnuri in 1992, KORDI commenced a full-scale national program for nodule exploration. The total area surveyed by KORDI covers more than 1,500,000 km2. At the end of 1993, based on the collected data, Korea designated 300,000 km2 in the Clarion-Clipperton fracture zone as prospective mining area for manganese nodules, and accordingly, the government of Korea submitted the application in January of 1994 to the United Nations for registration as a pioneer investor and for the allocation of a pioneer area. This application was approved by the General Committee of the Preparatory Commission in August 1994. As a result, Korea became the 7m pioneer investor under the United Nations Convention on the Law of the Sea. KORDI is now carrying out detailed exploration survey and environmental studies in the registered area to fulfill required obligations to UN, and Korea will continue exploring the last frontier on earth. It is KORDI's unshaken calling to be successful in exploiting deepsea resources to provide our nation resources it lacks. It is not only a challenge to explore deepsea, but it is also our national mission to explore and succeed in our endeavor for future generation.

Jan 1, 2011

By C. Wildman

Prospectivity modeling of seafloor massive sulphide (SMS) deposits has been completed over the Kermadec Arc-Colville Ridge area using the GIS based weights of evidence and fuzzy logic modeling techniques. SMS deposits are the current equivalent of ancient onshore volcanogenic massive sulphide (VMS) ore deposits. These high-grade deposits are formed on the seafloor and commonly consist of a black smoker and metal rich sediment mound complex resulting from the discharge of hydrothermal fluids (up to 400°C) from fractures on the seafloor. Metal sulphides are continuously precipitated in response to mixing of high-temperature hydrothermal fluids with ambient seawater. Accumulation of metal sulphides has led to SMS deposits being potentially major sources of copper, zinc, lead and other metals such as gold, silver, which to date remain untapped. Modeling of SMS deposits was undertaken to illustrate the power of GIS modeling for seafloor resource evaluation and how it can be used to quickly identify and rank in terms of the most likely prospective areas of the seafloor where new SMS deposits might exist. The mineral deposit modeling was constrained by the mineral systems concept which defines those parts of a mineralisation system that are critical to the ore-forming process. The deposits are typically formed in extensional tectonic settings, including both submerged tectonic margins and sea-floor spreading. Volcanic vent systems and underlying dykes, stocks and sills are the sources of heat that are responsible for converting sea water drawn down through fractures in the oceanic crust into an ore-forming hydrothermal fluid. This fluid is then capable of leaching metals and elements from surrounding footwall rocks, which are then transported upwards via the convection of hydrothermal fluids. The ore materials are then precipitated within the black smoker field as massive sulphides due to the mixing of high-temperature (250-400°C), metal-rich hydrothermal fluids with cold (about 2°C) oxygen bearing seawater.

Jan 1, 2011

By Andrea Koschinsky

Ferromanganese crusts have traditionally been considered a potential ore for Co, whereas ferromanganese nodules have typically been considered a potential ore for Ni and Cu. However, both nodules and crusts sequester high concentrations of many metals (Table 1) from sediment pore waters and seawater, many of which are essential for high-tech applications. The resource potential of these rare and valuable metals is poorly known and they are the subject of considerable current research. The need for adequate and dependable supplies of these metals is essential for the development of new technologies. The rare-earth elements have recently received much attention in the scientific and popular press because of their use in so many high-tech applications and because more than 95% of the production comes from China (e.g., Service 2010); consequently, there is concern about the possibility of a significant decrease or even curtailment in exports from China. The lack of a primary source and the inadequate supply of Te have prohibited the development of a Cd-Te photovoltaic solar-cell industry (Hein et al. 2010). Inadequate supplies of many of the elements listed in Table 1 are limiting the development of key high-tech industries, forcing the use of alternative metals that [ ] may result in less efficiency or less favorable properties for a product. The rare-earth elements, Te, and other elements listed in Table 1 occur in high abundances in marine hydrogenetic and diagenetic ferromanganese deposits. Here, we look at the mechanisms by which these rare and valuable metals are incorporated into different genetic types of marine ferromanganese deposits.

Jan 1, 2010

By Sang Joon Pak

Deep-sea mineral resources explored by Korea are categorized into mainly three types; manganese nodules, manganese crusts and seafloor massive sulfides. Manganese nodules have high Pt enrichment factors (EF=400, ore/crust ratios). Rare earth oxides (REO) contents from manganese nodules show from 0.037 to 0.302 REO% with mean value of 0.12%. Te and Pt are highly enriched in manganese crusts, displaying EFs of 10800 and 150, respectively. REO contents of manganese crusts are slightly richer than manganese nodules (0.013~0.387 REO%, average = 0.18 REO%). Seafloor massive sulfides deposits are featured by outstanding values of Se (EF=1300) well as In (EF=110). Au (0.8~26.3 g/t) and Ag (0.9~348.0 g/t) are another enrichment metals in SMS, although they belong to precious metals. Rare earth elements of SMS are meaningless as resources but REE are increasing in sediments overlying SMS. Heavy rare earth elements (HREE) from both manganese nodules and manganese crusts are typically higher than ones from land-based REE deposits. HREO grade and their portions of manganese nodules as well as manganese crusts are greatly similar to ion-absorbed type REE deposits in China, implying REE of subsea mineral resources are absorbed in nodules and crusts. Rare metals including REE could be exploited as by-production of commodities such like Ni, Co, Cu and so on. Rare metal resources from manganese nodules and manganese crusts are featured by low-grade and large scale deposits. Therefore rare metals in subsea mineral resources will add its economic values.

Jan 1, 2011

By Doug Lockhart

The Marine Minerals Technology Center has taken advantage of recent price and performance .improvements in PC hardware and software to upgrade its seismic acquisition system. In the past, single channel, high resolution, seismic data was displayed on an analog plotter and stored on tape. Associated navigation data was logged by hand or on a chart plotter. The navigation and seismic data were synchronized with time so that they could be cross referenced. The Center's new system uses PC's for the acquisition of both seismic and navigation data. Off the shelf software products were purchased for each task. Elics Delphl performs the seismic acquisition and processing, and GeoResearch, Inc. Geolink provides the navigation interface. A navigation string is sent from the navigation PC to the seismic PC via an RS232 line. This string consists of a time and location fix, as well as speed and heading data. The navigation string is then imbedded in the header of the seismic record. The Geolink software is capable of monitoring other devices in addition to the GPS used for positioning. Device inputs are attributed to the location data to provide easy construction of a navigation GIs. Currently the Center is logging fathometer data along with the navigation. As a result, a map of bathymetry along the tracklines can be available shortly after completion of the cruise.

Jan 1, 1992

By Wilfred Lus

Meaningful and real time environmental monitoring of marine tailings placement is a clear sign of deeper commitment to the people of PNG in regard to impacts of mining on coastal environment and marine life. Today daily mine wastes and tailings are increasingly being delivered to the seabed offshore of project sites in Misima and Lihir islands. Ramu and Simberi mining projects also plan to dispose tailings out at deep sea. As tailings leave the tailings pipe and come out into the seabed, concentrations of the cations and other potential harmful particles in the tailings stream need to be quantifiably monitored each day during the life of the refinery. For continuous monitoring of the tailing?s true chemical characteristics submarine cables connected with ocean floor observation systems consisting of deep-sea underwater video, and cation sensors and electrodes will be laid. Power transport to the tailings site and data transfer from the tailings site will be via opto-electric cables. Various data center instruments will record and manage the collected data. Observation data will be transferred in real time to stake holder?s data centers via a dedicated line from on-land stations, and then distributed to company offices and government establishments. Japan Marine Science and Technology Center, Telikom PNG, and Australian Institute of Marine Sciences will be the key advisers in this project. The main role of the observatories is to monitor and collect background seabed geochemical data prior to start of tailings disposal, during tailings disposal period, and after the life of the refinery.

Jan 1, 2001

By Richard H. T. Garnett

Diamonds were discovered on the coast of Namibia in 1907 but it was not until 1962 that the first gems were produced from offshore by a barge employing an airlift. Geophysical surveys and a sampling program were initiated and an understanding of the diamond distribution was gained. Several vessels, some with multiple airlifts, were used until the early 1970's. Some spectacular production results were achieved, but generally the systems failed to retrieve the gravels efficiently from beneath the overburden and off the bedrock. Various companies continued working with mixed outcomes until the mid-1980's, when new regulations were enacted by the authorities. The local Southern sea conditions dictate the present mining methods which are now applied over several hundred kilometers of the west coast. In shallow waters divers operate from small vessels, suctioning the diamondiferous gravels to surface with gravel pumps. In water depths of up to 50 m airlifts of various designs continue to be utilized with recovery plants installed on the vessels. Beyond 100 m depths a remote controlled, tracked, vehicle is used, together with a large drill mounted on swell compensator. Each system is deployed from a separate ocean-going vessel. Production of diamonds from the offshore is rising rapidly, with expectations of further increases. The coastline is likely to be the scene of new developments in marine mining techniques.

Jan 1, 1992

By Andrew E. Grosz

The Atlantic Continental Shelf (ACS) of the United States includes about 391,000 km2 extending from the shoreline to the 200-m isobath. It varies in width from a fraction of a kilometer (offshore of southern Florida) to about 150 km (offshore of Cape Cod, MA). The contained volume, of sand and gravel is estimated to be on the order of 3-7 x 1.011 m3. Concentrations of potentially commercially important heavy minerals (HM) exist locally, particularly in high-energy depositional environments (for example in channels, tidal deltas, ridge and swale areas, and submerged former shoreline complexes). Recently completed and ongoing studies of HM assemblages in vibracore samples from the south shore of Long Island Sound, NY, offshore of Ocean City, NJ, offshore of Cape May, NJ, offshore of the mouth of Chesapeake Bay, VA, offshore of Myrtle Beach, SC (grab samples), and the ACS offshore of Florida provide the information base for this presentation (Table 1). The surficial sediments of the ACS contain local concentrations of HM that compare favorably to those in currently mined onshore deposits as shown

Jan 1, 1988

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 The DY125-33(Leg 2) Science Parties, Chuanshun Li, Xuefa Shi, Bing Li

"The slow-spreading Mid-Atlantic Ridge (MAR), with a length of ~1.26*104km (Bird, 2003), is the longest mid-ocean ridge on this plant. Separated by the large, left-stepping Equatorial fracture zones, it then be divided into two approximately equal-length parts: Northern Mid-Atlantic Ridge (NMAR, ~6292km) with an average spreading rate of 24mm/yr, and Southern Mid-Atlantic Ridge (SMAR, ~6332km) of 33mm/yr (calculated from PB2002 model, Bird, 2003). Previous works (e.g. Fouquet 1997, Hannington et al., 2011) suggest that slow-spreading ridge could support hydrothermal activities and further favorable for the development of extensive seafloor massive sulfide deposits (SMS). Unlike the NMAR for which large part has been explored for SMS (Hannington et al., 2011; Beaulieu et al., 2015), the SMAR is amongst the least hydrothermal explored spreading ridges until now (Haase et al., 2005, Beaulieu et al., 2015), though both of them show significant similarities in terms of spreading rate, ridge morphology, segmentation, etc. (Macdonald et al., 2001, Sandwell et al., 2014, Tucholke et al., 2008).Before this work, several hydrothermal cruises had been to SMAR since British and German programs starting in 2002, some hydrothermal fields, along with systematic geophysical data, were newly investigated, and types of geologic setting that can host hydrothermal activity were firstly identified (e.g. German et al., 2008; Haase et al.,2005; Haase et al.,2009; Devey et al.,2010; Schmidt et al.,2011).."

Jan 1, 2017

By Virginie Tilot de Grissac

This project funded by Government of Flanders (Belgium) and coordinated by the Intergovernmental Oceanographic Commission proposes to draw recommendations for conservation of the biodiversity and for minimizing the impact of future nodule mining from the description of the referential state of suprabenthic megafaunal assemblages within a nodule ecosystem in the Clarion-Clipperton Fracture Zone (CCFZ). The description of this specific ecosystem is based on the analysis of about 200 000 photographs and some 55 hours of film collected by French and American exploratory cruises. The video and hotographic sampling has been achieved by means of different towed and remote control devices designed for Ifremer and NOAA including the manned submersible “the Nautile.”

Aug 24, 2006

By Virginie Tilot

Recommendations have been drafted following an international multidisciplinary panel discussion organized at UNESCO/IOC by the Académie des Sciences d?Outre-Mer on 15 December 2010 conveyed, according to its mandate, to the French government and to an international pool of scientists and stakeholders. These take into consideration the relevant Provisions of the United Nations Convention on the Law of the Sea of 10 December 1982, the Rio ?Earth Summit? Convention of Biological Diversity of 5 June 1992 as well as the activities and recommendations implemented for the world?s oceans and seas, in particular by the International Seabed Authority (ISA) and the recent reports and scientific works (including those implemented by the ISA Kaplan, Ifremer, COI-Unesco). The recommendations integrate, for one of the ecosystems, the conclusions of the project of the conclusions of an IOC-UNESCO / Government of Flanders project (2004-2010) implemented by Dr. V. Tilot from 2004 to 2010, during which were published three volumes describing the referential state of the polymetallic nodule ecosystem and proposing options for the management and conservation of the nodule ecosystem in the Clarion Clipperton Fracture Zone, NE Pacific Ocean: http://unesdoc.unesco.org/images/0014/001495/149556f.pdf, http://unesdoc.unesco.org/images/0014/001495/149556e.pdf; http://unesdoc.unesco.org/images/0014/001495/149556e.pdf#223

Jan 1, 2011