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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 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

By Darryl Thorburn

The Cook Islands are 15 islands located in the Southwest Pacific (between 8-23°S latitude and 156-167°W longitude). The total land area is about 200 km2. However, because its islands are widely scattered, the EEZ of the Cooks encompass an area about 2 million km2. The Cook Islands government exercises sovereignty and jurisdiction over its EEZ according to international law and convention as a member state under UNCLOS1. Accordingly, the Cook Islands government exercises full control over resources in its EEZ, including minerals on the seabed. Decision making on allocating licences for exploration and ultimate mineral recovery is by the Cook Islands government and will be set out in relevant statutes. Seabed minerals investigations within the EEZ of the Cook Islands and adjacent waters were first carried out by, USSR, US, and New Zealand research vessels in the late 1960 early 1970?s and indicated the presence of high concentrations of manganese nodules. This early work was followed by a number of Government funded surveys in and adjacent to the Cook Islands EEZ These surveys have identified a world class resource of manganese nodules within the Cook Islands EEZ (CI EEZ), containing significant

Sep 14, 2011

By V. K. Banakar, R. P. Rajani, A. R. Chodankar

The Afanasiy-Nikitin Seamounts (ANS) in Eastern Equatorial Indian Ocean (Figure 1) are shown to be the exposed part of the presently buried 85°E Ridge system under the Bengal Fan sediment and were emplacement around 75-80 m.y. ago (Krishna, 2003). The first recovery of ferromanganese crusts from the ANS was made during 1994, and the samples (Figure 2) provided important clues on the evolution of this seamount (Banakar et al., 1997).

By U. Schwarz-Schampera, P. Stoffers

The main characteristics of the 2545 km Tonga-Kermadec subduction system are the subduction of the Pacific Plate and its sedimentary cover in the Tonga-Kermadec trench and the extension and rifting of the lithosphere behind the active island arc in the Lau basin - Havre Trough back-arc systems. The subduction of the Louisville Seamount chain at 25.6°S affects the tectonic and volcanic system and separates the island arc into the Tonga arc and the Kermadec arc, respectively. To the west, a Miocene island arc is represented by the Lau-Colville ridge. The crustal extension between the Lau-Colville and the Tonga-Kermadec ridge started at about 6 Ma, and induced their separation and the onset of the southward rifting since about 5 Ma. Characteristics of the Tonga-Kermadec arc system include (i) the fourthfold decrease of the subduction rate from 24 cm/a in northern Tonga to 6 cm/a in the southern Kermadec trench, mainly north of 23.5°S; (ii) the development from fast spreading in the Lau basin (16 cm/a) to slow rifting (2 cm/a) in the southern Havre Trough with the transition from spreading to rifting at 23.5°S; (iii) variations in the composition and the volume of the subducting sediments and rocks (detritus from the Samoan hotspot at the northern Tonga arc; the aseismic Louisville ridge at the southern Tonga arc; increasing terrigenous sediments from New Zealand at the southern Kermadec arc); (iv) a number of active volcanic centers younger than 1 Ma and characterized by significant shallow submarine hydrothermal systems.

Aug 24, 2006

By Janine Lahr, Peter E. Halbach

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

Sep 24, 2006

By Marco Figoni

The increased interest on deep water minerals resources is a challenge for both mining and oil industry. The exploration and production of oceans minerals require a synergy between of different technologies. While mining industry is leading the dredging and processing part of the system, oil industry is contributing through development of ore lifting technology based on existing subsea knowledge. The paper presents an overview, based on published projects around the world, of different approaches to marine mining. Several exploration techniques and offshore production systems were already designed and assessed, all of them with apparently positive results. Exploration phase is well advanced and in continuous expansion allowing the discovery of increasing resources around the world of different nature but production can be considered to be in an early stage. Different from onshore mining, subsea operations require a closer cooperation with international and local authorities to preserve as much as possible the environment. There are still many uncertainties at respect and all the exploration process must be carefully evaluated to allow subsea mining to develop in a sustainable manner. Technically, mining at seabed was already demonstrated and the process is based on three main components, namely seafloor mining tools, riser and lifting system and production vessel support. This layout is based on the concept that ore must be disaggregated at seafloor first, transported to surface in form of slurry that must be dewatered before loading to be transported to processing plants onshore. The challenges are rising because the environment and safety must be taken into consideration as a priority when evaluating the efficiency of the system. The most critical challenges regarding the production operations, especially in deep water are the deep-sea excavation process, the transport of large slurry volumes, the slurry abrasivity, the power supply management and the subsea

Sep 14, 2011

By H. L. Gibson, U. Schwarz-Schampera, Mark Hannington

Ancient ore deposits provide important clues for the understanding of the origin and distribution of modern submarine hydrothermal systems. An analysis of the formation conditions, tectonic settings, and preservation of ancient seafloor mineral deposits from the recent geological past to the late Archean sheds light on the time-space relationships and diversity of mineral deposit types likely to be found in the modern oceans. Microplate tectonics that characterized ancient ore-hosting greenstone belts were strikingly similar to those active in volcanic arc environments of the western Pacific today. In such complex settings, oblique collisions, opposing subduction zones, and rapid changes in stress regimes (e.g., from compressional to tensional and back to compressional) were common, causing juxtaposition of diverse styles of mineralization. The world-class base metal deposits of the late Archean Abitibi greenstone belt of Canada, for example, were formed within a relatively short time span of ~20 m.y., in response to successive arc rifting, back-arc basin development, and exhumation of accretionary complexes along major arc-parallel crustal-scale faults. Similar processes and environments are important settings for metallogenesis in modern submarine volcanic arcs. Active marginal basins of similar size and representing similar stages of evolution are well represented in the western Pacific today and contain a similar suite of mineral deposit types. Examples from the eastern Manus Basin and adjoining New Ireland Basin (PNG) and in the Lau-Tonga-Kermadec arc-backarc system illustrate these similarities. Certain gold-rich volcanogenic massive sulfide deposits at the southern margin of the Abitibi greenstone belt (e.g., Bousquet and LaRonde deposits in the eastern Blake River Gp.) may be important ancient analogs of newly discovered gold-rich black smoker deposits found along the active fronts of today's submarine volcanic arcs.

Sep 24, 2006

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 D. J. Scarratt

Fisheries make a significant regional contribution to the economy of Canada. In the Atlantic Region, over 70 thousand workers depend on the primary or secondary fishing industry. Fisheries are vulnerable to pre-emption of space by other marine industries and to contamination by chemical discharges. Markets may be affected even by the threat that products may be tainted. Fish may be killed by drags and dredges, and their physiology and behaviour affected by suspended sediments are stirred up by mechanical devices. Virtually no evidence exists of adverse impacts £ran ocean mining on fisheries, but projections from other marine activities such as fishing itself, dredging and other marine discharges give reason for caution. Department of Fisheries and Oceans policy calls for review of ocean mining proposals to ensure adequate protection of fish stocks, fishing activities and fish habitat, and compensation for losses attributable to any industrial project. Adverse impacts can be minimized by careful attention to details of location, technology and timing, and to close co-operation and information exchange between industry and the regulatory agencies.

Jan 1, 1985

By Lauro Calliari

Detailed geological studies using side scan sonar, bottom sampling and piston cores along the Rio Grande do Sul inner continental shelf and coastline indicate the occurrence of elongate deposits of calcareous shells fragments containing high calcium carbonate content. On the inner shelf these deposits lie at a depth between 15 and 50 meters and have been interpreted as ancient shorelines. They occupy an area of 965 km2 with a economic potential of 1 billion tons. Chemical analyses indicate a mean composition of 34.8% of calcium; 0.16 ppm of fluoride. According to the regional economy such composition make it highly recommended for a variety of uses including poultry feed and cement.

Jan 1, 1995

By Tetsuo Yamazaki

The importance of cobalt-rich manganese crusts on the Pacific seamounts for possible future rare metal sources has currently been recognized. The thin layer-type deposit characteristics affect not only the excavation efficiency but also the economy of mining venture. Considering the thin layer-type distribution and the utilization of some rare metals in cobalt-rich manganese crusts, a preliminary economic feasibility of the mining venture is evaluated. Under some preliminary technical assumptions, the possibility of cobalt-rich manganese crusts for future rare metal sources for Japan is examined. The important role of utilization of rare metals in the crusts is highlighted.

Jan 1, 2010

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 R. K. H. Falconer, Wood R. A., C. D. Castle

"A deposit of phosphate nodules is on the Chatham Rise approximately 450 kilometres to the east of Christchurch in the South Island of New Zealand. The deposit contains sufficient rock phosphate to supply New Zealand’s phosphate fertilizer needs for at least 20 years. It was first investigated commercially 50 years ago by Global Marine, followed by JBL Minerals in the early 1970’s. NZ and German government research and industry groups then took it up again, with major field programs in 1978 and in the early 1980s.Due to difficult global and local economic conditions the project ground to a halt in 2004.The project was resurrected in 2007 when Chatham Rock Phosphate applied for a prospecting licence. This was granted in 2010 and a successful subsequent mining permit approval followed in 2013. The initial application for the separately required environmental permit was declined in February 2015.A lot has changed then and the significance of this will be the subject of the presentation. Chatham Rock Phosphate is confident that an environmental permit will be successfully granted next time."

Jan 1, 2017

By W. H. Pelton

Polymetallic sulphide (PMS) deposits have recently been discovered associated with hydrothermal vents on the sea floor off Vancouver Island, B.C. Visual estimates indicate reserves in excess of 1 million tons. Reliable reserve estimates have not yet been made, however, due to the extreme difficulty of drilling cores in 2 km of water. Few geophysical techniques can aid in the exploration of these deposits. There is little or no difference in radioactivity, magnetic susceptibility or electrical resistivity between the deposits and the surrounding sea floor sediments. This precludes radiometric, magnetic, electromagnetic and resistivity methods. There is a density contrast, but the logistics of gravity surveys at such depths are formidable. The physical property which shows the most contrast with the sea floor sediments, and which is perhaps one of the easiest to measure (with modern equipment) is polarizability. The induced polarization (IP) method is one of the major electrical geophysical techniques for exploring for PMS deposits on land.

Jan 1, 1985

By Derek V. Ellis

Sediment Quality Guidelines can provide target values that should not be exceeded when seabed deposits are disturbed for mining, waste discharge or other purposes. Three sets of Guidelines have appeared in 1994 and 1995: US NOAA (updated from 1991), Environment Canada (EnvCan) and Equilibrium Partitioning (EqP) developed in the UK from US Water Quality Criteria. The US NOAA and EnvCan Guidelines have been developed by comparing many experimental and site data sets, and have concluded that levels below which effects rarely occur, or above which probably will occur, are useful guidelines. US NOAA uses the terms ERL and ERM for these two levels, and EnvCan TEL and PEL. The EqP concept is that a value can be calculated below which trace metals present cannot raise the concentration in the interstitial water. There are some problems in comparing units, but the comparison shows in general that the EnvCan levels are less than, and down to half of, the US NOAA levels. EqP levels vary but are generally fairly close to US NOAA ERL levels, with one major exception. The EqP level for mercury is far lower than either US NOAAor EnvCan levels, at 0.008 mg kg-1 compared to 0.15 (ERL) and 0.13 (TEL) mg kg-1 respectively. Comments will be solicited on how such differing Guidelines should be used site-specifically for environmental management at mining operations, (1) in the regions for where they were developed, and (2) elsewhere.

Jan 1, 1995

By Patrick J. C. Ryall

Remotely control led drills capable of being lowered to the sea-floor from ordinary research vessels have been developed over the past two decades. These drills are currently being used in geological survey programmes on the continental shelves (Canada, Japan, Norway, United Kingdom) and for studies of mid-ocean ridges. Generally the drills fall into two categories: 1) those which are powered from the surface and controlled by an operator, and 2) those which are battery powered and follow an automatic programme. Some drills have a television camera mounted on them sending a picture to the surface as an aid to site selection and geological interpretation. Typically the drills are capable of drilling a core 2.5 - 5 cm diameter up to 10 m long. While most of these drills are designed for <1000 m depth, some can drill in water depths of as much as 3500 m.

Jan 1, 1985

By W. D. Siapno

Marine mineral resources have been reviewed in great detail on numerous occasions over the past few years. A summary of these efforts would indicate there is little new on the horizon as far as economic programs are concerned. Deep ocean minerals, though not forgotten, hold little promise for development in the immediate future, i. e., manganese nodules, cobalt crusts, polymetallic sulfides, etc. Nearer to shore, within the EEZ, and particularly within waters under state control greater industrial interest is expressed. Interest in sand and gravel not only persists but is growing, dependent largely upon the construction industry. Precious metals demonstrate the greatest growth potential.

Jan 1, 1988

By Malcolm Clark, Robin K. H. Falconer

There are a number of likely impacts from mining operations, but a key issue is uncertainty about the environmental effects of sediment plumes created by disturbance to the seafloor and discharge of processed waters. The New Zealand National Institute of Water and Atmospheric Research (NIWA) is undertaking a research project to improve understanding of such impacts (relevant to both mining and trawl fisheries), by examining the extent and persistence of sediment plumes, the immediate impact and subsequent recovery of seafloor exposed to these plumes, and the effect on functioning of ecologically significant species. The project will use a combination of field survey experimentation with in situ observations and controlled laboratory-based experiments. The field work begins in May 2018 when an area of up to 1km2 at depths of 400-500 m on the Chatham Rise, 450 km east the New Zealand South Island will be subjected to disturbance by an upgraded former NOAA Benthic Disturber. The suspended sediment load created by the disturbance will be tracked and monitored, with the effects on seafloor animals examined by pre-and post-disturbance sampling. A wide range of seafloor sampling, benthic landers, towed cameras, oceanographic moorings and water column monitoring will be carried out over a three week period. Monitoring surveys will be repeated in 2019 and 2020 to determine the longer-term resilience and recovery of disturbed communities. The laboratory-based side of the programme, also starting in 2018, involves holding live deep-sea corals and sponges in tanks at NIWA, and exposing them to various levels and duration of particle loads in the water in order to reveal lethal thresholds as well as sub- lethal effects of settled and suspended sediment.

Jan 1, 2018

By Yoshio Masuda

Cobalt-rich crust in rich Co, Ni, Mm and Pt will be a potential resources for island country such as Republic. Marshall Islands. This study was conducted for Marshall Islands by the President Kabua?s request. It covers crust resources, CLB mining, processing, and economic estimation, and study concluded feasible veiw.

Jan 1, 1991