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By D. Cronan

Both the S.W. Pacific and Caribbean island arcs are host to submarine hydrothermal mineral deposits, the former more so than the latter. In the S.W. Pacific, the whole gamut of such deposits occurs on the sea floor, sulphides, silicates, Fe and Mn oxides, whereas during the limited studies to date in the Caribbean only hydrothermal Mn oxides have been found to occur on the sea floor there in any abundance. Comparisons between the respective Mn oxides are thus the most fruitful at the present limited stage of our knowledge of Caribbean submarine hydrothermalism. Southwest Pacific hydrothermal ferromanganese oxides and their possible relationships to underlying sulphide mineralisation or bedrock anomalies (the geochemical window concept) has been a fruitful field of research in recent years. Certain element enrichments in crusts may be indicative of underlying mineralisation (Rogers et al. 2001). However, more recent studies on buried hydrothermal crusts in the S.W. Pacific (Cronan et al. 2002) have shown there to have been postdepositional diagenetic uptake of elements in them, and thus these elements cannot be used with any confidence in geochemical exploration for buried sulphide deposits unless sediment involvement can be eliminated.

Jan 1, 2002

By Gerald R. Dickens

Massive sulfide ores and Fe-Mn oxyhydroxide precipitates represent two extremes of a spatial continuum of hydrothermal deposition along oceanic ridges. Elemental variations across this continuum are of interest to economic geologists as a prospective geochemical exploration tool. Theoretical considerations suggest that certain physical and chemical parameters can be used to model compositional variations within the far-field (i.e., Fe-Mn oxyhydroxide) component as a function of distance from ridge axis; however, testing and verification of such models generally has been precluded because the few available distal hydrothermal sediment sequences have been sampled at low resolution and/or are highly diluted with biogenic components (e.g., siliceous and calcareous tests). Recent ocean drilling (ODP Leg 145; Sites 885/886) in the North Pacific successfully recovered an extensive record of "biogenic-free" distal hydrothermal precipitates from an area approximately 60 km south of the Chinook Trough at longitude 168.1 °W. Geophysical and geomorphological evidence suggests the Chinook Trough is the southern lithospheric scar marking initiation of late Cretaceous north-south rifting, implying that recovered hydrothermal materials record distal hydrothermal precipitation from the now-subducted Kula-Pacific spreading ridge. The Chinook Trough hydrothermal sequence is a continuous 15 my record of "biogenic-free" hydrothermal Fe-Mn oxyhydroxide precipitation mixed with eolian clays. It was deposited during the late Cretaceous, early Paleocene (80-65 Ma) as the perpendicular distance from ridge axis increased from 75 to 600 km. A high-resolution geochemical analysis of this hydrothermal sequence reveals distinct trends for the up-core (equivalent to increasing distance from ridge) distribution patterns of Fe, Sc, As, and rare earth elements (REE). Iron concentrations exhibit an S-shape distribution pattern with respect to increasing

Jan 1, 1994

By Carlos Almeida, Bruno Matias, Stef Kapuskiak, Eduardo Silva, José Miguel Almeida, Alfredo Martins

Underwater intervention operations have been supported by robotic systems such as remotely operated vehicles (ROV) for a long time. In particular challenging scenarios such as the deep sea, the use of ROV systems for environment awareness is in fact the main tool of choice. With the technical advances in autonomous robotics, there is an increased effort in substitute ROVs whenever possible for autonomous underwater vehicles (AUV). These systems don't have tether and thus provide large advantages from the operations and logistic point of view. However the limited options for underwater communications render them impracticable for many tasks were real time environment awareness and direct human control is needed. Emerging applications in underwater mining, both at sea [1] and in inland flooded mines [2] pose additional requirements in terms of operation support needs and environment restrictions. Two main tasks are to be addressed by assisting robots in these underwater mining operations: providing adequate environment awareness for human operators and obtain precise realtime 3D environment modelling (particularly relevant for the mining planning). The use of ROVs with umbilical cable, has in this case large limitations due to the nature of the mining cutting (performed by dedicated systems) that limit manoeuvrability and pose high risk of cutting the cable or damaging the vehicle. In this paper we present EVA (Exploration VAMOS AUV) an innovative hybrid ROV/AUV system developed for operations support in inland underwater mining operations. This robot is always operated without tether, and the can be used in a wireless ROV tele-operation mode using very short range high bandwidth underwater communication systems and in autonomous AUV mode.

Jan 1, 2018

By Tetsuo Yamazaki

Natural methane hydrate has been scientifically studied as a global carbon reservoir. However, in Japan, it?s potential as an energy resource has been industrially highlighted, because there are few domestic oil and natural gas resources in Japan, but many potential deposition areas for methane hydrate in the sea around Japan. Less CO2 discharge from methane compared with coal, oil and conventional natural gas for the same calorie value is considered an advantage for its use as an energy resource. Because methane hydrate is distributed at shallow depth in sediments on the ocean floor, accidental leakage of methane may occur while we utilize methane hydrate. Methane itself has a considerable impact on the greenhouse effect, if it reaches the atmosphere. Therefore, it is necessary to estimate its behavior in the environment after leakage if we want to use methane hydrate as energy resource. The mass balance after leakage of methane on the seafloor and in the water column can be studied through the analyses of natural cold seepages and hydrothermal activity.

Jan 1, 2004

By Charles L. Morgan

In a commercial effort to characterize deep seabed manganese deposits in the Clarion-Clipperton region of the northeastern tropical Pacific, Ocean Mineral s Company carried out 16 expeditions to the region between -1978 and 1981. During these cruises OMCO collected substantial data. Activities included acoustic profiling, video and photographic imaging of the seabed, and sampling of the deposits with dredges, box cores and free-fall grab samplers. In 1990 the samples, photographs, technical reports and computer data bases which resulted from this work were archived at the Marine Minerals Technology Center at the University of Hawaii. This preliminary examination of the collection focuses on the biological observations made from almost 10,000 photographs of the seabed and the manganese nodule size distributions and compositional data from the free-fall grab recoveries. Regional trends are evident in all three data types. The biological examinations of the seabed photographs show significant geographical trends, with greater abundances of organisms being noted in the northeastern extreme of the region, decreasing toward the southwest (11.4 to 2.7 observations per 100 m2; 460 to 190 g per 100 m2). The nodule size distributions suggest that the ratio of the nodule burial rates to growth rates systematically decreases over the same range (0.65 to 0.36 nodules buried per 1 cm of growth). Preliminary geostatistical analysis of the ore grade data show that, in addition to high local variability, some deposit

Jan 1, 1991

By Pia-Maria Haselberger, Marc Schiemann, Christian Frühling, Nicolas Richter, Hendrik Wehner, Andreas Kaschube

"The paper provides the principle considerations for a novel vehicle class within the scope of the project Large Modifiable Underwater Mothership (MUM). The main idea for these ships is to create a highly modular building block system for the global layout. This building block system allows for a mission-dependent module assembly. For the purpose of deep sea mining for example, the range of tasks reaches from multipurpose transportation and exploration missions to supporting tasks in up to 5000 m depth, e.g. energy supply. Topics covered in this paper are related to potential missions for these vehicles, the modular layout and the structural layout of a separate block module. The paper closes with a conceptual design example for this class.Index Terms—MUM, UUV, underwater mother ship, autonomous underwater vehicle, modular, deep sea, conceptual designI. INTRODUCTIONAs one of the leading economic nations, Germany is in need of energy and raw materials. In the 21st century, marine resources are a prominent and promising alternative to land based resources. However, there are challenges that need to be considered. Rough and often poorly plannable weather conditions prevail distant to the marginal seas. Ice coverage makes offshore services inefficient and costly in Polar Regions. The average ocean depth of 3500m and the associated environment conditions cause difficulties in fulfilling tasks in the deep sea. The project Large Modifiable Underwater Mothership (MUM) [1] will enable more efficient solutions in order to accomplish undersea duties and services in harsh conditions.This joint project comprises workshares from Atlas Elektronik, EvoLogics, thyssenkrupp Marine Systems, the University of Rostock and the Technische Universität Berlin. The principle idea of the project is the conception of a novel vehicle class. With highly modular autonomous underwater vehicles, this class will be capable of undertaking a variety of different tasks. Classically engineered vehicle structures will be split into single basis modules which can be flexibly assembled with specialized mission modules to form potent systems for individual assignments. The group of basis modules consists of units for navigation, vehicle control, propulsion and energy generation via fuel cell technology. The potential reusability of system relevant modules leads to a significant cost reduction and to shortened development periods compared with conventional vehicle concepts. The integration of newly designed additional mission modules is possible with little effort and a separate commercialization of single modules is feasible."

Jan 1, 2017

By William D. Siapno

Approximately a century lapsed between the time nodules were discovered and the beginning of commercial exploration in the early 1960's. A period of rapid development of exploration and mining technology ensued over most of the next two decades. In recent years advancement has been sharply curtailed. This paper discusses the constraints inhibiting nodule mining and some developments that could aid in overcoming certain difficulties. Specifically, the greatest single constraint is economic. With few exceptions mineral markets are badly depressed. Present projections for development of nodules are for the late 1990's or beyond. However, the U.S. awarded exploration licenses in mid-1984 and more recently boundaries of license areas have been released. These conditions promote cooperation among organizations engaged in deep ocean mining. Survey data, and where appropriate some data products, have been exchanged between various consortia. The present hiatus in at-sea activities provides an excellent opportunity to investigate the best means to proceed. This period of quiescence offers a rare moment to distill the meaningful values of an era of hectic activity to permit more efficient development in the future.

Jan 1, 1985

By Gregory J. Kurras

In 1995 the Marine Minerals Technology Center (MMTC) of the University of Hawaii conducted a sidescan sonar survey and sampling expedition of the submarine geology and hydrothermal systems surrounding the active volcano White Island. The island is located in the Bay of Plenty, within the geothermally active Taupo Volcanic Zone off-shore of the North Island of New Zealand, and is the site of numerous shallow-water hydrothermal systems. The survey system, an EdgeTech DF1000 sonar, was a dual frequency 100 kHz & 500 kHz sonar capable of imaging the seafloor at better than 1 m resolution and possibly detecting gas bubbles within the water column. Sidescan imagery clearly shows sand channels, debris slumps, submarine landslides, and volcanic ridges all around the island to roughly 800 meters offshore. However, analyses of the both raw and processed acoustic data indicate that the sonar was not able to image any of the shallow-water hydrothermal gas seeps known to exist around the island. Vents were located using a commercial fish finder and knowledge from local tour guides and divers. Eleven gas samples from three different sites were collected by divers for analysis of chemical and isotopic composition. Rock samples were collected from thirteen underwater outcrops for correlation with existing data on subarial island flows sampled by previous investigators. Thin sections and XRF analysis were done for each rock to determine mineral assemblages along with major and trace elements, which were used to tie submarine samples to specific subarial stratigraphic layers.

Jan 1, 2011

By Dilip Sarangdhar

"SeaTech Solutions International (S) Pte Ltd, Singapore are the designers of world’s first seabed mining ship. The ship is now under construction and expected to be delivered next year. The Deep Sea Mining industry is eagerly awaiting commencement of her seabed mining operations and the success of this story will go a far way in accelerating investment in Deep Sea Mining and hopefully we should see many such projects take off and many such ships launched in the near future.Based on own experiences SeaTech discusses in this paper, various important issues that need to be considered for design of such Deep Sea Mining ships, the challenges faced and possible solutions to address them.From a ship designers’ perspective, there are not many direct previous references available, the seabed mining methods and associated equipment are also a new technology & products are still developing, there is no standard method and equipment for processing of mineral ore onboard, and above all there is the huge challenge of loading, storage and discharge of ore cargo efficiently in the confines spaces. Associated with the uncertainties of such issues is the uncertainty of weight, space, power, services and maintenance requirements, which can vary through the design and construction period and put the initial ship design at huge risk. Sufficient design margins need to be provided and a constant & strict control is absolutely necessary to ensure that the budget on each technical aspect is not exceeded. The local strength of the vessel particularly needs to be robust to take ultra-large loads due to huge equipment and their lifting /handling equipment/winches and tall mining process modules."

Jan 1, 2017

By Peter E. Halbach, Andreas Jahn

"Co-rich ferromanganese crust deposits exist on slopes, summits and platforms of seamounts and guyots throughout the global oceans, where deep-sea currents have kept the seafloor structures more or less free of sediment for millions of years. They form by direct precipitation from cold seawater under more or less oxic conditions and consist of thin layers (2 up to 25 cm thick) covering hard substrate rocks in water depths of 800 to 5000m (Halbach and Marbler, 2009; Hein et al., 2000). Besides Mn these crusts contain interesting concentrations of minor elements (Co, Ni, Ti and Cu) and trace elements (Mo, W, Te, Ga, Pt and REEs), thus they represent significant metal deposits and promise potentially valuable additions to the world’s metal resources.The prospects for mining of this marine type of metal deposits largely depend on the grades and the scale of the potential ore resources. However, only a few percent of existing seamounts and guyots have been mapped and sampled in detail, most of them in the Pacific Ocean. Therefore, a model to estimate the geological resources based on the global seamount catalogue of Wessel (2001; revised: Wessel et al., 2009) and the empirical parameters which control the metal composition and distribution was developed."

Jan 1, 2017

Recent focus by terrestrial mineral explorers (and investors) on cobalt has increasingly highlighted the future critical need for this metal, with new-age batteries being the primary utilisation. We present an overview of the world’s current terrestrial cobalt resources and put this in perspective of currently known seabed resources, particularly polymetallic nodule and crust deposits. We focus on comparison of the key exploration, development and exploitation risks for such deposits, and provide a framework for financial evaluation and appraisal.

Jan 1, 2018

By Wiebe Boomsma

This is a framework study financed by the Maritime Innovation Programme of The Netherlands and several institutions actively involved in the research of the environmental impact of deep sea mining; IHC Mining, MTI Holland, Delft University of Technology, NIOZ, IMARES, Boskalis Westminster, AllSeas and TNO. For this framework study the following mining activities have been identified to be relevant to assess the ecological impact of a deep sea mining operation: a) excavation, b) tailings return, c) vertical transport, d) vessel operations, e) ore transport and f) general operations. For this paper, only one mining activity has been selected as an example for the assessment of ecological effects. This is one of the main activities introduced by the new technology envisaged for developing deep sea mining: tailings return.

Sep 14, 2011

By Peter Halbach

Hydrothermal activity is well known from many locations on most mid-ocean ridges, however no hydrothermally mineralized area had yet been found at the ultraslow spreading southwest Indian Ridge up to October 98 when the Japanese RV Yokosuka with the submersible Shinkai 6500 investigated this area. A massive sulfide field was discovered near 27º51S / 63º56 E in the 11th segment west of the Rodriguez Triple Junction. The Free University of Berlin had joined this cruise and taken over the responsibility for the study of the respective sulfide mineralizations. Hydrothermal minerals were sampled during two dives at water depth of about 2940 m close to the summit of an axial volcanic ridge called Mount Jourdanne. There massive sulfides occur on the seafloor as small smooth mounds with an average area of about 5 m2. Their surfaces are weathered and have a reddish to brownish colour. In addition to these mound-like structures, small tube-like chimneys were observed. These chimneys rise approximately 30 to 40 cm above the floor and are less than 10 cm in diameter. No indications of hydrothermal fauna could be detected. All the hydrothermal features are spatially related to faults and smaller fissures controlled by an E-W trending graben system crossing the summit region of the submarine volcano. Such tectonized areas are generally considered to be ideal for hydrothermal activity because they may have both a magmatic heat source in the deeper underground and pathways for fluid circulation, respectively.

Jan 1, 2001

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 Peter E. Halbach, Andreas Jahn

Co-rich hydrogenetic ferromanganese crusts are typical marine interface products of growth processes taking place on sediment-free substrate rocks on the seafloor. They grow very slowly and preferentially in water depths below the oxygen-minimum zone (OMZ) and have so far been found even in water depths of up to more than 5000 m, i.e. also below the calcite compensation depth (CCD); these deep ferromanganese crusts are particularly rich in Fe. It is assumed that the O2-minimum zone is the most important source layer of dissolved manganese, the decomposition of fecal pellets here also contributes to this Mn-budget. The process of hydrogenetic precipitation is basically an inorganic colloidal-chemical as well as a surface-chemical mechanism. Microbial mediations can be assumed, in particular since steps of redox-reactions are involved. The two main components of the hydrogenetic substance are hydrated d-MnO2 (vernadite) and x-ray amorphous Fe-oxyhydroxide, both of which are intimately intergrown with each other forming the extremely fine-grained hydrous oxidic material. In seawater, elements occur as dissolved hydrated ions or as inorganic as well as organic complexes which, in general, have either a positive or a negative surface charge depending on the pH of the respective marine environment. These complexes form hydrated colloids that interact with each other or with other dissolved hydrous metal ions. The main agent to oxidize the dissolved Mn2+ ions is oxygen, transported upwards from deeper water by turbulent eddy diffusion and turbulent rise processes at seamount slopes.

Jan 1, 2017

By Lisa Koch, Eleanor Martin

"Each underwater mining project is different. However, most have one thing in common: To be successful. We will draw on our experience advising hundreds of international clients each year on mining, offshore oil & gas and shipping matters to highlight some legal, commercial and practical issues to consider when structuring underwater mining projects. We will look at new ways of allocating risks and rewards in order to obtain much needed investment for underwater mining projects to commence both the exploration and exploitation phase.HighlightsRisk profileWe will look at a typical underwater mining project from the viewpoint of an investor and highlight some of the perceived risks, and potential mitigants.Contractual structureWe will analyse how the mining industry and oil & gas service industry have responded to low commodity prices to examine innovate contractual arrangements with suppliers and stakeholders, and how they can be tailored to the underwater mining industry. FinancingWe will explore some potential financing structures which could be relevant to the underwater mining industry."

Jan 1, 2017

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 Andrea Koschinsky

Numerous hydrothermal vents occur along the Earth?s oceanic spreading axes documenting the reaction of seawater with hot magmatic rocks. The circulation of seawater through the oceanic crust, the interaction with hot rocks in the crust, and the subsequent discharge of hot metal- and gas-rich fluids into the ocean have significant implications for the cycling of material and energy on Earth. Until recently, hydrothermal activity was unknown from the Mid-Atlantic Ridge (MAR) south of the Equator where the MAR is offset by about 1000 km at the St. Paul?s and Romanche fracture zones. During a British cruise in February/March 2005, the first active hydrothermal vent field was discovered on the southern MAR at 5°S. During our follow-up cruise M64/1 in April 2005, the first samples from this vent field were recovered with the ROV QUEST (Univ. Bremen) and analyzed onboard. The high-temperature vent field is situated in a water depth of 2990 m along a line of collapse pits within a large basaltic sheet flow. A diffuse, low-temperature field occurs in a jumbled sheet flow few hundred meters to the east with warm water streaming out of cavities between lava blocks. Here we show for the first time that boiling fluids of ~400°C are emanating from sulfide-bearing vents at a depth of about 3000 m at a slow-spreading Mid-Atlantic Ridge segment. Although this segment is composed of thick basaltic crust, these fluids are dominated by hydrogen relative to methane. Whereas the active chimneys consist of pyrrhotite, chalcopyrite, and isocubanite, the mineral association hematite-magnetite-pyrite occurs in the inactive chimneys suggesting that the fluids became more reducing in present times. The high hydrogen contents and the high temperature of the fluids as well as the change to more reducing conditions are most likely related to a young volcanic eruption event some 300 m east of the hydrothermal field. The presence of hematite and magnetite may indicate that the upflow zone or even the reaction zone at 5°S used to be more oxidized then at other MOR sites, where the hydrothermal fluids are commonly buffered by the pyrite-pyrrhotite-magnetite (PPM) buffer. Consequently, high iron contents and high hydrogen/methane ratios occur in high temperature fluids from basaltic host rocks rather than being restricted to ultramafic host rocks. Faunal communities at the South Atlantic vents largely resemble those from the North Atlantic vents implying that the large Equatorial fracture zones do not inhibit or obstruct faunal exchange along the Mid-Atlantic Ridge.

Jan 1, 2005

By Joshua Brien

DEEP SEABED MINING IN NATIONAL JURISDICTION: KEY CHALLENGES The talk focuses on the key challenges that arise from deep-seabed mineral exploration and development within areas of national jurisdiction, including legal and institutional challenge and options to address these challenges. Joshua Brien has acted for a range of Governments throughout the world, including smallisland States and the developing world. This has included engagement in matters before the International Court of Justice, the Tribunal for the Law of the Sea in contentious and advisory proceedings, including provisional measures applications and prompt release cases.

Jan 1, 2018

By V. Alexandrov

This paper presents the results of theoretical investigations of the energy requirements of the hydraulic lifting of mined materials from the seabed to the sea surface in the deep-sea mining of solid minerals such as manganese nodules in the Clarion-Clipperton region of the Pacific, situated on the sea floor in water depths of 4,500 m or more. The principal element of the developed underwater transport system is the Underwater Chamber, which is connected by flexible pipeline to a mining machine that gathers nodules from the seabed, mixes them with seawater, and feeds them into a flexible pipeline. In this paper, we discuss the question of the optimum water depth for placement of the Chamber, the interior of which is designed to maintain a 1-atmosphere pressure. We present a method for calculating this depth as it relates to the mechanical characteristics of solid particles, the shapes and size distributions of the particles, particle and slurry density, and other properties. These investigations were carried out in hydro-transport laboratory of the Saint-Petersburg Mining Institute and the hydraulic laboratory of Faculty Environmental Engineering in Wroclaw Agricultural University. KEY WORDS: deposit, nodule, flexible pipeline, pressure drop, concentration, hydromixture

Jan 1, 2005