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By Lorena Blanco, Guillermo Gómez-Ramos, Iker Blasco, Egidio Marino, Luis Somoza, Ricardo León, Teresa Medialdea, Javier González

"This study presents the first catalogue of marine mineral deposits and energy resources along the continental margin of Spain. Aggregates, oil and gas and metalliferous mineral areas have been defined and mapped. The catalogue, implemented in a geographic information system (GIS), is conceived as a first national database within the European network, which is being built as part of the EMODnet-Geology project. It comprises 8 types of mineral and energy resources for the Spanish margins: aggregates, hydrocarbons, evaporites, placer deposits, phosphorites, polymetallic sulfides, polymetallic nodules and cobalt-rich ferromanganese crusts (Figures 1 and 2). The catalogue stores a total of 409 marine mineral deposits and compiles information such as name, deposit type, main morphology, main minerals, setting or area extent for each mineral deposit. By number of deposits compiled, the aggregates are the most abundant (286) followed by hydrocarbons (62), cobalt-rich ferromanganese crusts (32), evaporites (9), placer deposits (8), phosphorites (5), polymetallic nodules (4) and polymetallic sulphide deposits (3). Considering the total extension, hydrocarbons (32,386 km2) and cobalt-rich ferromanganese crusts (24,951 km2) represent the biggest areas.The Geological Survey of Spain (IGME) is developing a new tool in the catalogue, according the International Seabed Authority (ISA) Database parameters, for individual samples on each ferromanganese deposit. The database includes an extensive collection of records that comprise five information groups: general cruise and sample data, physical properties, mineralogy, geochemistry and acronyms used. New attributes have been incorporated, in example: geophysical, sedimentological and petrological data in the deposit area, sample weight, porosity, morphology, textural and structural features, geochemistry of major, minor and trace elements (included REEs and PGEs) and supplementary cruise and laboratory reports. This new database complements the EMODnet-Geology project minerals catalogue, offering a deeper level of information for the areas with major potential for mineral or energy resources as they are the Canary Island Seamount Province, the West Margin of Galicia and the Gulf of Cadiz."

Jan 1, 2017

By Henk van Muijen, Jan Willem de Wit

1.1 Profile IHC Holland Merwede IHC Holland Merwede is world market leader in the construction of specialist dredging equipment and large-size custom-built offshore vessels. The clients of IHC Holland Merwede include major dredging companies, oil and gas exploration groups, offshore contractors and government authorities. IHC Holland Merwede is focused on the continuous development and innovation of technology to ensure maximum performance and efficiency of its designs and constructions supplied to the dredging and offshore industries. IHC Holland Merwede has a staff of approximately 2,000 at its locations in Hardinxveld- Giessendam, Kinderdijk, Krimpen aan den IJssel, Sliedrecht, Delfgauw, Goes, Hendrik Ido Ambacht and Heusden. Besides worldwide representations, IHC Holland Merwede has branches in China, Houston (USA), India, the Middle East and Singapore. 1.2 Mission IHC Holland Merwede’s mission is to optimize value by anticipating and satisfying its client’s requirements, with efficient advanced technology solutions. The group’s aim is to be consistently at the forefront of technology development, in the business sectors in which it operates.

By Jeremy Spearman, Alan Cooper, Mark Lee, Jon Taylor, Michael Turnbull, Neil Crossouard, Bramley Murton

"SUMMARYSeamounts are underwater mountains caused by volcanic activity. They are of great oceanographic interest because of their local and basin-scale influence over ocean systems, their often unique ecosystems, and because they are associated with the formation of ferromanganese (Fe-Mn) crusts. These crusts are of particular interest to scientists because they are rich in some of the rare elements increasingly required for development of renewable technologies. When the possibility of mining such seamounts is considered, an inter-disciplinary study of seamount hydrodynamics, crust formation and ecosystem sensitivity is required. MarineE-tech is one such multi-disciplined project that has been commissioned to address these different aspects in order to improve understanding of the viability and desirability of mining Fe-Mn crusts. This paper describes a key part of this study, namely the development of a model, informed by hydrographic observations, of the currents around one such seamount and the in situ validation of a sediment disturbance plume model as a pre-cursor to assessment of the potential effects of mining activity.INTRODUCTIONFerromanganese crusts are thought to form by precipitation of iron and manganese oxides from oxygen depleted mid-water known as the oxygen minimum zone (OMZ). Oxidation rich waters, typically at depths of about 800-2200 m (Hein et al, 2000). This range of depths coincides with the flanks and summits of many seamounts. The ferromanganese crusts found on seamounts have been found to have high concentrations of rare elements, like Tellurium, that are considered critical to low-carbon energy production. Seamounts are complex environments: in terms of the local hydrodynamics that tend to trap water over the seamount due to the Taylor Cap effect (e.g. Chapman and Haidvogel, 1992) and which can enhance the productivity of seamount waters through upwelling (Lavelle and Mohn, 2010), in terms of the microbiological activity that leads to the precipitation of the Fe-Mn crusts, and also in terms of the often unique ecosystems that are the product of the “island” nature of seamounts and the upwelling of nutrients. The understanding of this complexity is a necessary journey towards the realization of viable, yet environmentally responsible, mining schemes. The formation of crusts will be influenced by the local (and larger-scale) hydrodynamics. The exploration of promising crust sites could be made much more efficient by understanding where the most prospective deposits are likely to occur. Knowing how to remove these crusts without impacting significantly on the local environment will be a pre-requisite for such mining to be acceptable to the public and funders alike."

Jan 1, 2017

By T. Schoening

The exploration of the seafloor regarding the abundances of poly-metallic nodules has received growing attention recently. Image-based exploration using cameraequipped deep-sea observation systems has been introduced successfully to increase spatial resolution in the exploration process but the evaluation and interpretation of the huge amount of image data creates a serious bottleneck. In this paper we present a new software solution to the problem of automatic detection and segmentation of poly-metallic nodules in underwater images, which is not only accurate but so fast that real time image analysis is definitely in reach. Thus, an application on an AUV (Autonomous Underwater Vehicle) seems possible in the near future.

Sep 14, 2011

By Alexander Malahoff

Six active Kermadec arc submarine volcanoes located between 34°S and 36°30’S were mapped and sampled by an interdisciplinary inter-institutional research team between April and July 2005 using submersibles Pisces V and Pisces IV aboard the mother ship the R/V Ka’imikai-o-Kanaloa. The purpose of the expedition was to study the relationship between hydrothermal activity, formation of hydrothermal mineral deposits, and the biodiversity of life associated with the hydrothermal vents. Of the volcanoes examined, all showed evidence of hydrothermal activity, including metal-rich plumes and helium anomalies. Only two of the volcanoes, namely Brothers and Clark, showed chimneys and surficial polymetallic sulfide deposition. Hydrothermal venting at a water depth of approximately 1,650 meters near the base of the northwest caldera wall of Brothers volcano has produced a field of chimneys, some of them seven metres high and discharging black smoker venting. Temperatures up to 300°C were measured from the active vents. Clark volcano has a double cone summit at a water depth of 875 meters. The shallowest cone has a near-summit hydrothermal vent field with five-meter tall venting chimneys with smaller structures around the periphery.

Aug 24, 2006

By Tim J. Boyd

Gregg Marine, Inc. (headquartered in Signal Hill, California) has recently introduced an innovative seafloor drill system for offshore geotechnical site investigation and seafloor mineral exploration. The system is capable of working in water depths of up to 3,000 meters and is rated to drill to a depth of approximately 150 meters below mudline. The remote operated system integrates established drilling technology with proven Schilling telemetry and controls. The flexible nature of the patented wireline drilling technology enables the use of standard sampling systems (up to PQ-size core and 3? thin-walled tubes) as well as downhole testing systems (including CPT testing, vane shear testing, downhole sensors and borehole geophysical tools). The modular nature of the seabed drill system and the accompanying launch and recovery system (LARS) enables the use of local vessels of opportunity for projects resulting in reduced project costs and improved mobilization responsiveness times. Keywords: seafloor, seabed, geotechnical, drill, drilling, core, coring, sampling, CPT, cone penetration testing, borehole, logging, survey, exploration, ROV, remote sensing

Jan 1, 2011

By Michael Johnston

Nautilus Minerals is exploring for high-grade gold, silver, copper, and zinc-rich submarine massive sulphide deposits (SMS) within the territorial waters of the sovereign state of Papua New Guinea. Work to date has shown that these systems contain spectacularly high metal grades. To date a total of 88 surface sulphide grab samples have been collected from Nautilus’ Solwara 1 Prospect within EL 1196 in the Manus Basin, returning average grades of 15.5 g/t gold, 191g/t silver, 10.8% copper, and 4.7% Zn. Drilling in January/February 2006 confirmed the presence of this high grade system, with sulphide intersections up to 19m below the sea floor, with a best intersection of 11.6m at 9.1 g/t Au and 13.1% Cu.

By LeRon E. Bielak

Public Law 103-426 was signed into law in October 1994. Its provisions amended sections 8(k) and 20(a) of the Outer Continental Shelf Lands Act (OCSLA). The 8(k) amendment provides the Secretary of the U.S. Department of the Interior 001) with new discretionary authority to negotiate agreements for using Outer Continental Shelf (OCS) sand, gravel, and shell resources for certain projects of public benefit (e.g, beach, shoreline and coastal wetlands restoration that are under- taken by a Federal, State or local government agency). The new law also covers construction projects that are funded wholly or in part or authorized by the Federal Government. Under the law, the Secretary may assess a fee for use of the resource by taking into consideration the value of the resource and the public interest served. The law also requires that any Federal agency proposing to make use of OCS sand, gravel, or shell resources enter into a Memorandum of Agreement (MOA) with the DOI. An MOA would promote efficient coordination and resolution of inter- agency scheduling and issues. The law requires that Congress be notified before use is made of these OCS resources. The amendment to section 20(a) of the OCSLA clarifies that obligations concerning environmental studies extend to non- competitive lease situations and includes minerals other than oil and gas. The Minerals Management Service (MMS) is the DO1 agency responsible for interpreting and implementing the provisions of Public Law 103-426. The negotiated agreement approach is distinctly different from the competitive bidding requirements that have applied to all OCS minerals since the inception of the OCSLA. The MMS has opted to implement the new law in a nontraditional manner. Rather than issuinga body of new regulations to cover the negotiated agreement situation, or attempting to amend three sets of existing regulations, MMS is pursuing a less formal approach of providing guidelines. More weight is placed on the negotiation process itself and the legal agreement that consummates the process as the means for establishing ground rules, terms, and conditions under which qualifying projects may be conducted. This process must recognize and adhere to requirements of other laws, including the National Environmental Policy Act.

Jan 1, 1995

By S. C. W. de Jong, E. de Hoog, J. M. van Wijk, S. J. Dasselaar

Introduction Technology development for sustainable, safe, reliable and efficient mining of polymetallic nodules in the deep seas requires careful design, thorough understanding and integrated testing of all equipment, physical processes and (sub) systems involved (Dasselaar et al [1]). Proceeding from Vertical Transport System (VTS) experiments at IHC laboratory scale by Van Wijk [2], with typical system dimensions of several meters, to prototype or pilot scale testing with typical dimensions of several kilometers, is a giant leap. Naturally, intermediate steps are required in order to mitigate the possible risks in the full-scale system’s (physical) processes. Within the EU program Blue Mining (2014-2018), possibilities emerged for performing experiments at intermediate scale: the so-called medium-scale vertical slurry experiments. Near Freiberg, Germany, the village Halsbrücke possesses a 140 meter deep empty vertical mine shaft, perfectly suited for housing the test setup. For this purpose, a 318 meter long 145 mm pipeline circuit was constructed, including both a 130 meter high vertical riser and fall pipe section. A purpose-built sediment injection and separation system was deployed, including a 55 kW centrifugal pump. The riser section has been equipped with sensors capturing pressure, temperature, flow velocity, volumetric concentration and flow visualization. The planning, modification and construction of the test facility site itself is described by Müller et al [3]. The present paper describes the objectives, experimental program, equipment, and the preliminary results. Publications on in-depth results are foreseen in the (near) future.

Jan 1, 2018

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 Jonguk Kim

Hydrothermal exploration aboard the R/V Onnuri was performed along the northern Central Indian Ridge (CIR) between 8°S and 12°S in January 2010. The main objectives of this first Korean research cruise on mid ocean ridge system was 1) to understand the nature of spreading segments of the northern CIR area, where no systematic survey have been operated before, by mapping and sampling of volcanic rocks and 2) to discover new hydrothermal venting along the spreading center of northern CIR. During the first leg (IR09 Leg1) bathymetric data, in ~50 km width, were collected by multibeam echo sounding system (EM120), which reveals the exact location and structure of axial rift valley of northern CIR between ~ 8°S and 17°S. Then, rock sampling and CTD casts and tows were performed in northern half of the multibeam survey area in the second leg (IR09 Leg2). The results of bathymetric survey clearly display ocean core complex between 10°S and 11°S. The ocean core complex is featured by topographic-high area with corrugated surface. Lineament of corrugations of the ocean core complex are clearly perpendicular to abyssal hill direction which are triggered by symmetric-normal faults. Symmetrical and asymmetrical segments are characterized by parallel abyssal hills and ocean core complex and/or subparallel abyssal hills, respectively. Geochemical analyses of basaltic glasses from spreading axis show geographic trend of increasing of incompatible elements north to south along the spreading axis, which might be influenced by Reunion hotspot plume. However, local but clear enrichment of incompatible elements is observed in volcanic lava from segment 2, which suggests possible local mantle heterogeneity of uncertain source. Lots of serpentinite and gabbroic rocks with coarse-grained feldspar was recovered in the ocean core complex. Ultramafic and/or mafic rocks indicate the gentle-domed block was traveled from upper mantle. Along the spreading axis of the northern CIR, significant hydrothermal plume signatures were detected by CTD castings and tows. Plume signatures were observed at all 5 surveyed segments, suggesting vigorous hydrothermal activities along the northern CIR. However, the optical signals (light transparency and backscattering) of the nearly every cast along the axial valley of the CIR showed increased background level, which might be due to higher level of suspended particles within the axial valley not only by widespread hydrothermal plumes but also by other processes like resuspension. Onboard dissolved methane analysis indicates that the greater part of the plume signals are originated from hydrothermal venting, not by resuspension. However, more detailed examination, including analyzing additional hydrothermal tracers, need to distinguish actual hydrothermal plume signature.

Jan 1, 2010

By Cornel E. J. de Ronde, Alexander Malahoff

Six active Kermadec arc submarine volcanoes, located between 34°S and 36°30'S were mapped and sampled between April and July 2005, using submersibles Pisces V and Pisces IV aboard the mothership R/V Ka'imikai-o-Kanaloa. The purpose was to study the relationship between hydrothermal activity, formation of hydrothermal mineral deposits, structure of the volcanoes, and the biodiversity of life associated with the hydrothermal vents. Of the volcanoes examined, all showed evidence of hydrothermal activity, including metal-rich plumes and helium anomalies. Only two of the volcanoes, namely Brothers and Clark, showed chimneys and surficial polymetallic sulfide deposition. Hydrothermal venting at a water depth of approximately 1,650 meters near the base of the northwest caldera wall of Brothers volcano has produced a field of chimneys, up to seven meters high and discharging black smoker venting. Temperatures up to 300°C were measured from the active vents. Clark volcano has a double cone summit at a water depth of 875 meters. The shallowest cone has a near-summit hydrothermal vent field with five-meter tall venting chimneys with smaller structures around the periphery. Water temperatures of 200°C were recorded for these chimneys.

By Fernando J. A. S. Barriga

Exploration for active seafloor hydrothermal vent fields has been highly successful, and more than 300 such fields have been discovered to date. Some will most probably be mined, given their high metal grades (Cu, Zn, Au and others). However, the current practice detects active systems, and activity rates, not the size of the deposits. This strategy may leave undetected some of the best targets, for several reasons as follows: 1. Large hydrothermal plumes are a measure of dispersion of ore components, not of efficiency in the generation of orebodies; 2. Deposits formed a few hundred years (or more) before present will generally have ceased their activity and will not be detected by plume studies; 3. Deposits formed under a cover rock (up to a few meters of sediments, volcaniclastics, or the like) may exhibit only minor seafloor hydrothermal activity, possibly diffuse flow. Cover rocks will often host hanging wall rock alteration, expressed in geochemical and mineralogical haloes. It has been demonstrated in many instances, especially for deposits formed in the geological past, now exposed on land, that ore genesis under a cover rock is one of the most suitable processes for generating large massive sulfide deposits. One of the great challenges for submarine resource knowledge will be to develop adequate exploration strategies for sizeable orebodies, not necessarily hydrothermal vent fields, sometimes hidden under a cover rock.

Jan 1, 2011

By Fernando J. A. S. Barriga

"Recent concerns over the availability of many mineral raw materials, and newly available technological developments, produced renewed interest in deep-sea mining. However, environmental concerns, with variable degrees of justification, are raising opposition to the concept. The forecast for the behavior of consumption versus availability of many raw materials, nearly all critical metals, arguably show that consumption will grow much faster than resource discovery onshore. Finding new sources of raw materials seems inescapable. The deep seafloor stands out as the only likely candidate.Sea Floor Mining and the EcosystemMarine mining has already started, decades ago, for diamonds, currently up to depths near 400m. Although the industry recognizes there is a footprint, it considers the footprint quite minor, because the area mined is small: in Namibia, where offshore diamond mining is now 70% of the country’s total, only 3% of the concession of 3,700 sq miles (9600km2) have been mined. As plans to mine deep-sea massive sulphide deposits and polymetallic nodules progress, the environmental concerns grow. Some of these concerns are as follows:?The deep-sea ecosystems are composed of long-lived species, with low rates of reproduction. The environment may not recover from mining on a human time scale;"

Jan 1, 2017

By John Parianos, Simon Richards

SUMMARY The Clarion Clipperton Zone (CCZ) hosts the most valuable deposit of polymetallic nodules yet discovered. Understanding the geology of this deposit is key to its effective exploration and mining. Nautilus Minerals (via its subsidiary Tonga Offshore Mining Limited; TOML) has been progressing its understanding of the relationship between seafloor morphology/structure and nodule abundance/morphology, both locally (within its contract areas), and globally (across the CCZ and the span of its contract areas of almost 70% of the CCZ). We present the first results of a project with the aim of developing a method to quickly and accurately map seafloor morphology/structure (Tectonic Subcomponent scale) without the necessity for high resolution seafloor multibeam data. Furthermore, the results presented here will allow a first attempt in understanding the relationship between seafloor geomorphologically-defined zones and plate-scale tectonics of the CCZ and adjacent plate segments. INTRODUCTION A relationship between the type of geochemical active layer and nodule abundance/morphology has long been understood (ISA, 2010). Consideration of the range of differing nodule types found within, but especially between, the TOML contract areas allowed Parianos and Pomee (2017) to refine this relationship further via interpreted thickness and dynamism of the geochemically active layer. The scale of the deposit, both in terms of space and time is staggering (a 10-20 cm thick deposit, spanning almost 4500 km, varying within a circa 10 Ma period), but a segment wide geological map may one day prove to reflect controls on nodule formation and distribution.

Jan 1, 2018

By Cornel E. J. de Ronde

Brothers volcano (34°51.7?S, 179°03.6?E) is a large caldera volcano that forms part of the active Kermadec arc south of 32° S, NE of New Zealand. It is an elongate edifice striking NW-SE that is ~11-13 km long by 7-8 km across. The caldera has a basal diameter of 3-3.5 km and is surrounded by 350-450 m high walls with the floor 1,850 m deep. A volcanic cone of dacite composition rises 350 m from the caldera floor and partially coalesces with the southern caldera wall. Much of the caldera construction and the location of the hydrothermal vent sites are controlled by intersecting basement structures. Three hydrothermal sites have been recognized at Brothers; NW caldera, SE caldera and cone. Multiple hydrothermal plumes were mapped from the bottom of the caldera upwards to a depth of 900 m and originate from two of the sites; one on the NW caldera wall the other atop the cone. Analyses of these plumes show that the two vent sites are chemically distinct. The cone site itself hosts three distinct vent fields (summit, upper flank, NE flank) that in 1999 had plumes (mainly from the summit) containing relatively high concentrations of gas with a shift of -0.27 pH units (proxy for CO2) and H2S concentrations up to 4,250 nM, particulate Cu (PCu) of 3.4 nM, total dissolvable Fe (TDFe) of 4,720 nM, TDMn up to 260 nM and Fe/Mn values between 4.4 and 18.2. However, in 2002 plumes from the summit vent field had noticeably lower concentrations of PCu (0.3 nM), TDFe (175 nM), and Fe/Mn values of 0.8, although similar TDMn (220 nM) and shift in pH (-0.22) suggesting a state of flux for this site. By contrast, plumes originating from the NW caldera site have much less gas with a pH shift of -0.09 units and no detectable H2S, TDFe up to 955 nM, TDMn up to 150 nM, and Fe/Mn values of 6.4, and have not changed their composition over the same three year interval indicating a more chronic hydrothermal system. Plume d3He results show helium is decoupled from more near-surface vent fluid sources although a shift in R/Ra values from 6.1 ± 0.5 in 1999 for the combined vent sites to 7.2 ± 0.1 in 2002 indicates a less radiogenic input of helium over three years, suggestive of a greater magmatic input to the system.

Jan 1, 2004

By Raymond A. Binns

Exploration for undersea polymetallic sulfide mineral resources with high economic potential would be more effective given an ability to predict sites with particularly high gold contents (averaging say > 10 ppm Au). Herzig et al (1993) addressed this issue shortly after recognition that deposits in the back-arc Lau Basin (average 3.8 ppm Au) were enriched in gold relative to mid-ocean ridge sites (average 1.2 ppm Au). Small but significant numbers of hydrothermal sites with massive sulfide deposits averaging >10 ppm Au have since been discovered. The principal genetic factors underlying gold enrichment include depositional processes at and below the seabed, and the source of gold. It is timely to consider whether resolution of their relative importance can be translated into practical criteria for exploration strategies focused on especially gold-rich deposits. Comparing the ?grade? of seafloor deposits using analyses cited in research papers is fraught with difficulty, but there is no alternative at present to assuming that such averages provide an initial tenor guide. On this basis, four known polymetallic hydrothermal sites from convergent plate margins fit the exceptional-gold category with >10 ppm ?average? Au, while one from a divergent margin comes close: Sunrise (Myojin Knolls; 20 ppm ?average? Au) and Suiyo Seamount (28 ppm Au) in the Izu-Bonin Arc are frontal arc volcanoes dominated by rhyolite and dacite respectively, contrasting with more common mafic neighbor edifices (Iizasa et al., 1999). In both cases gold-rich massive sulfides occur in summit calderas with significant development of pumiceous volcaniclastic rocks, at depths around 1300 and 1370 m respectively. In the Eastern Manus Basin, PACMANUS (~1700 m; 14 ppm Au) and Suzette (~1550 m; 22 ppm Au) occur along the crests of volcanic ridges dominated by dacite/rhyodacite and andesite/mafic dacite respectively (Binns, 2004). Caldera structures are lacking. Although the Eastern Manus Basin is tectonically a rifted back-arc, its submarine volcanic edifices (picritic basalt to rhyodacite) have distinctly arc-style geochemical and isotopic affinities, differing from more typical back-arc basin basalts at the spreading axis further west (central Manus Basin). Probably as a consequence of transpression and a marked rupture in the New Britain subduction zone, submarine arc volcanism has here extended into the rifted back-arc region.

Jan 1, 2005

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 Karsten Hagenah, Tor Jensen, Jens Laugesen, Øyvind Fjukmoen, Lucy Brooks

This paper discusses operational environmental threshold levels for exploitation of mineral resources in the deep sea. Such criteria are needed to be able to monitor and control deep sea mining with respect to the stringent environmental requirements that are needed. It is recommended to use existing environmental threshold levels for comparable underwater activities. Fields of application are mainly but not exclusively seabed mining operation activities under the governance of the International Seabed Authority (ISA). The threshold levels and limits mentioned in this paper are proposed recommendations based on other activities than seabed mining but are a proven and accepted approach in other maritime industry activities. An example of such other activities with proven and accepted environmental threshold levels are Oil & Gas exploitation activities in the sea. Background The first exploitation of mineral resources in international waters is coming closer. Presently regulations for exploitation for mineral resources in the Area are being developed by the International Seabed Authority (ISA). The ISA regulations will contain the framework related to environmental monitoring of exploitation. However, the regulations will not contain operational environmental threshold levels for the Contractor.

Jan 1, 2018

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