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By N. R. Ayupova

Several metallogenic zones including Sakmara, Magnitogorsk, and East-Ural zones were revealed in the Ural fold belt (Fig. 1). These zones are considered to be the paleogeodinamic sectors corresponding to marginal sea, island arc system, and uplift respectively. Ferruginous-manganiferous sediments in the Southern Urals are hosted by the basalt-rich volcano-sedimentary series of the Magnitogorsk paleoisland arc system with West- and East Magnitogorsk island arcs and Sibai inter-arc basin. The manganiferous mineralization occurs in association with the Middle Devonian stratabound hematite-quartz rocks and bedded red jaspers localized on the foot or handing walls of massive sulfide deposits. Fe-Mn nodules are widespread in jasper horizons on the flanks of manganese deposits. We have studied Fe-Mn nodules from the Faizulino and Yanzigitovo Mn-deposits formed in the Sibai inter-arc basin and compared them with well known Fe-Mn nodules from modern oceans.

Jan 1, 2010

In 1983, the GEMINO research project (Geothermal Metallogenesis Indian Ocean) was initiated in order to locate and evaluate sites of recent or fossil hydrothermal activity in the largely unexplored Indian Ocean. During GEMINO cruises 1 and 2 with R/V SONNE in 1983 and 1986, the Central Indian Ridge between 21°S and 24°S was the subject of detailed exploration, including SeaBeam and magnetic mapping, hydrocasts, sediment coring, TV-grab sampling, and camera/video tows. Although hydrothermal sulfide mineralization was not located, a hydrothermal component in the sediment composition, hydrothermally altered basalts, and maximum concentrations of 27.5 nmol/kg Mn and 45.6 nl/l CH4 were discovered (Plüger and Herzig 1986; Herzig and Plüger 1988a). Leg 1 of the GEMINO-3 cruise in 1987/88 identified a neovolcanic ridge in the rift valley of a 30 km segment at 22°55'S as a site of weak hydrothermal activity and photographed smectite-like precipitates on basalt talus and a chimney structure on top of a ridge-parallel fault scarp. Water temperature data and the distribution of Mn and CH4 were interpreted as indicative of diffuse, low-temperature hydrothermal activity (Herzig and Plüger 1988b).

Jan 1, 1989

By Evgeny G. Gurvich

While direct study of high temperature hydrothermal activity and the associated mineral formation as well as study of their scales are possible in the modern ocean, researchers are deprived of such opportunity for past geologic time. Even in cases where hydrothermal deposits that formed in the geological past are preserved they have been covered by sediments or overlain by lava and have become inaccessible after a time for obser-vation and sampling. Rarely are these buried hydrothermal deposits found during deep-sea drilling or coring operations, and their direct study on an ocean scale is impossible at present. Even within hydrothermal fields, without special preliminary detailed surveys, the probability of intersecting hydrothermal edifices that are covered by sediments becomes a rare event.

Aug 24, 2006

By A. Ivanova

The continental shelves occupy a vast area of Russia and contain complexes of commercial placer minerals. Of prime importance are Cenozoic placers of valuable minerals including gold, cassiterite, diamonds, chromite, platinoids, and minerals of titanium, zirconium and rare earth elements, biogenic amber and fossil ivory (1). Commercial placer minerals are associated with shelf placer formation zones (SPFZ). These zones are located at junctions of marginal orogens and shelf troughs in morphostructures where upwarping, subsidence, and sign-variable neotectonic movements are not significant. The SPFZs are characterized by ancient buried leveling planes with mantles of waste, series of wave-cut aggradation terraces on land and beneath the sea, and drowned and buried stream valleys. The occurrence of mineral placers in the SPFZs was caused by endogenic mineralization and exogenic placer hosted formation. Concentrations of commercial biogenic minerals are associated with areas of burial of biogenic material (release of resins by plants and theriofauna thanatocoenoses) and with their transition zones. Since the Oligocene, alternations in marine transgression-regression have dominated the shelf areas. This has resulted in the formation of polygenic placers. Climatic conditions are of great importance: warm and humid climate in the Paleogene-Neogene changed to colder climates in the late Pliocene (polar type sedimentation; formation of permafrost strata and sea glaciation). These events are responsible for the regularity in placer formation during the Cenozoic in which the early Cenozoic (Eocene-Oligocene-Miocene) and late Cenozoic (late Pliocene-early Pleistocene and late Pleistocene-Holocene) epochs are prominent.

Jan 1, 2004

By Takashi Ito

Numerous studies have examined the distribution of deep-sea manganese deposits throughout geologic history. Here I summarize the recent results, focusing on the frequency of occurrence, burial age and mechanism, and the paleoceanographic implications.

By V. M. Hamza

Analysis of ground and airborne radiometric measurements in the Saquarema region (Rio de Janeiro) provides new insights into the breakdown and transport of mineral aggregates containing monazites, under sub-tropical weathering conditions. The breakdown process, accompanied by loss of low-density clay fractions in weathered materials is considered responsible for the observed patterns in relative enrichment of thorium and uranium along the migration paths of radionuclides. The characteristic features of these patterns provide clues as to the time and distance scales associated with processes of weathering and erosion. It is also possible to determine approximate locations of concentrations of accessory minerals. In this context, we advance the hypothesis that large under-water monazite deposits may be present along the offshore sand banks, in the coastal region of the state of Rio de Janeiro.

Sep 14, 2011

By B. S. Ingole, S. Jai Sankar, A. B. Valsangkar, R. Sharma, B. Nagender Nath, N. H. Khadge, P. A. Loka Bharathi

After the simulated ‘mining’ experiment (INDEX) in the Central Indian Ocean (in 1997); the restoration of benthic environment was monitored for 4 years (2001-2005) at 5 locations in and around the test site and at 3 reference stations (20-80 km) from the test site. A comparison of long-term monitoring data with the pre-mining and post mining observations has shown that: • The concentration of silt fraction which was the highest (50-60%) at most locations during ‘pre-mining’ and ‘post-mining’ phases, had reduced (40-50%) during monitoring phases. • There was a corresponding increase in clay concentration (50-60%) during the monitoring phase, implying change in the size of sediment particles settling on the seabed, a trend that was also observed at the reference locations. • The initial increase in water content and decrease in shear strength after the experiment, which appeared to be returning to normal in monitoring-1 (2001), was reversed during subsequent monitoring phases (2002-2005), indicating changes in benthic environmental conditions. • Sediment organic matter and pore-water chemical data have not only indicated partial restoration of geochemical properties after the experiment, but also cyclic changes during the monitoring period.

Oct 15, 2007

By Eleanor Martin

An examination of the draft Exploitation Regulations from an investor’s perspective. We will look at the commercial requirements of the investment community (debt and equity) in order to provide funding to a deepsea mining project, and contrast this with the position put forward in the draft Exploitation Regulations. We will then recommend suggested amendments to the Exploitation Regulations to assist future investment on this growing industry.

Jan 1, 2018

By Maria Thornhill, Rolf Arne Kleiv

INTRODUCTION The last decade has given rise to an increasing number of deep-sea mining concepts (DSMCs) outlining technical solutions for the production chain from seafloor mining to mineral or metal extraction. The vast technological and logistical challenges coupled with immature but rapidly evolving technology has spawned a great variety in proposed concepts, and the exact implications of the phrase ‘best available technology’ is very much an open question. DSMCs differ significantly with respect to choice of technology, technological readiness level, degree of resource utilization, logistics, OPEX and CAPEX requirements, overall profitability, legal and political implications, not to mention environmental impact. Hence, a system for classifying concepts could provide a useful identification and structuring tool when performing economic, judicial or environmental assessments of DSMCs, as well as offering a general terminology to describe concepts sharing fundamental traits. This abstract proposes a DSMC classification system based on how a concept makes use of mineral separation at the different stages in the ore’s journey from the deposit to the ocean surface and ultimately to onshore facilities. Mineral separation, as a process step, is the key factor in determining both the state and mass flow of materials along the production chain and has, as such, a decisive effect on economy and environmental impact of any deep-sea mining project. A DSMC that is based on bringing the entire volume of broken ore to onshore facilities for processing will look very different from a concept based on pre-concentration (i.e. mineral separation) at the seafloor. Whereas the latter offers savings in the form of reduced energy cost for vertical transport, it also represents a substantial additional technological challenge. Furthermore, whether or not a concept relies on mineral processing at the seafloor or on a floating facility at the ocean surface above the deposit also determines the point at which mineral separation waste (i.e. tailings) must be managed. Different concepts offer different opportunities for tailings deposition, and are at the same time bound by different requirements.

Jan 1, 2018

By Tobias Hens, Andrew Frierdich, Barbara Etschmann, Joël Brugger, Barrie Bolton

"Ferromanganese (Fe-Mn) nodules and crusts are prime targets for future deep-sea mining ventures due to their unusual enrichment of critical metals, such as Ni, Co, Cu, Ti, Te, Zr, Hf, Nb, Y, and REE. These metals are used in an ever increasing variety of high- and green-tech applications such as alloys, batteries for hybrid cars, fiber-optic cables, or liquid-crystal displays.1 Recovery and processing of these deposits will most likely be cost-intensive and require new solutions.2 Thus, innovative approaches towards the development of sustainable metallurgical processes represent one component that can positively affect the marine mining value chain. Dynamic mineral recrystallization of Fe- Mn oxide phases is a geochemical process that may have notable potential for future hydrometallurgical applications.Our research focuses on Mn oxides – potent trace metal scavengers with high sorptive capacity3 – and biogeochemical mechanisms that control Fe-Mn nodule and crust formation, alteration, and trace element enrichment. Biogeochemical redox cycling of Mn is characterized by microbial oxidation of aqueous Mn(II) to Mn(III,IV) oxides and (a)biotic reduction of these oxides to Mn(II)aq. During this cycling dissolved Mn(II) is in direct contact with solid-phase Mn(III,IV) oxides and can back-react via abiotic pathways (e.g., 4 and references therein). This results in continuous dynamic recrystallization of the Mn mineral substrate through coupled dissolution (trace metal release) – reprecipitation (trace metal incorporation) processes.4 We recently demonstrated in new experiments, that Ni is cycled during manganite recrystallization. It has been shown that, although Ni readily undergoes mineral-fluid repartitioning in the absence of Mn(II)aq, dissolved Mn(II) significantly catalyzes Ni exchange between solid phase and solution. Over a period of 50 days about 30 percent of the Ni atoms in Ni-substituted manganite (natural abundance composition) were exchanged with a 62Ni(II)aq isotope tracer at pH 7.5. Based on these outcomes we employed similar techniques to investigate the impact of dynamic recrystallization on Mn oxide phases in deep-sea ferromanganese nodules and crusts from three circum-Australian locations (South Tasman Rise, Lord Howe Rise, Coral Sea) and the Central Pacific Basin."

Jan 1, 2017

By Sally Philpot, Siân E. Boyd, Hubert L. Rees, Emma Bee, Carla Houghton, Ceri James, Silvana N. R. Birchenough, S. Limpenny David, A. Coggan1 Roger, Koen Vanstaen

Every year approximately 22 million tonnes of marine sand and gravel are dredged form British waters. The eastern English Channel (EEC) contains substantial reserves, a proportion of which have been identified by the aggregates industry for potential future exploitation. The main aim of this study is to produce broadscale marine habitat maps of the EEC area. The UK aggregates industry has formed a consortium of representatives (the eastern English Channel Association), and have sponsored an initial baseline survey and follow-up sampling programmes as part of a Regional Environmental Assessment (REA) covering a patchwork of aggregate prospecting areas. To complement this effort, a large-scale geophysical survey was conducted in 2005 to place the REA in a wider spatial context and, thereby, to help assess the environmental significance of any future impacts arising from commercial aggregate extraction over the broader region of the EEC.

Sep 24, 2006

By Rahul Sharma

Although, mining of minerals such as polymetallic nodules and sulphides from the deep sea floor has been delayed due to the combination of factors such as current availability of Cu, Ni, Co, Mn (and other metals) on land and their fluctuating prices; these deposits are still considered as the alternative source for metals in the 21st century. Exclusive rights for exploration in the ?Area? (beyond the national jurisdictions of any country) given to eight countries and consortia by the International Seabed Authority and the estimated resource of 300 million tonnes in a typical area of 75,000 km2 is expected to yield about $17.5 billion (at December 2008 metal prices) in 20 years life span of a single nodule mine-site. In order to recover 3 million tonnes of nodules, an area of 300 sq km only will be mined annually (i.e. <1 km2/day) for an optimum abundance of 10 kg/m2. However, during mining, large quantity (22 tonnes/day) of sediments associated with nodules would be resuspended that could lead to certain environmental impacts on the benthic ecosystem. Several small-scale benthic impact experiments in the Pacific and Indian Oceans, have given some insight into the possible environmental impacts and the restoration processes, but the possibility of extrapolating these findings to a commercial mining scale remains an issue to be considered. An estimated capital expenditure of $1.05 billion and operating expenditure of $4.2 billion for a single deep-sea mining venture will have to be weighed against the availability of mineral ores on land as well as the metal prices in the world market. None-the-less, development of technologies for mining and metallurgical processing, as well as formulation of regulations and guidelines for potential ?contractors? to mine these minerals have been progressing consistently. These coupled with recent efforts by certain ?entrepreneurs? to initiate mining of seafloor massive sulphides in the EEZ of certain countries, indicate the continuing interest and support the perception that such deposits could well be the future sources of metals. This paper analyzes the current status and discusses the economic, environmental, and technical issues that need to be addressed for sustainable development of deep-sea minerals.

Jan 1, 2010

By Tetsuo Yamazaki

Natural methane hydrate has been scientifically studied as a carbon reservoir globally. However, in Japan, the potential for energy resource has been industrially highlighted. There is less domestic oil and natural gas resources in Japan, but many potential deposition areas for methane hydrate in ocean around Japan are the reasons. Less CO2 discharge from methane compared with coal, oil and conventional natural gas when the same calorie value we get is considered as the advantage for energy resource. However, because methane hydrate distributes in shallower sediment layer in ocean floor, accidental leakage of methane may occur while we utilize methane hydrate. Methane itself has 21-times impact on the greenhouse effect, if it reaches the atmosphere. Therefore, it is necessary to estimate the behavior in the environment after the leakage, if we want to use methane hydrate as energy resource. The mass balance after leakage of methane on seafloor and in water column is numerically studied through the analyses of methane emissions from natural cold seepages and hydrothermal activities in this research. The outline structure of mass balance ecosystem model shown in Fig. 1 is introduced. A numerical early diagenetic model CANDI (Carbon And Nutrient Diagenesis) developed by Boudreau (1996) for simulating the biogeochemical processes such as organic matter, oxidant, nutrient, bi-product, and pH diagenesis in aquatic surface sediments and C. CANDI improved by Luff and Wallmann (2003) for describing the formation process of calcium carbonates in CANDI are used as bases of the ecosystem modeling in surface sediment layer around seafloor methane emission. Two functions such as methane bubble dissolution and bacterial methane oxidation in water column are added to an existing physical plume dispersion model by Doi et al. (1999).

Jan 1, 2005

By Maria Baker, Kristina Gjerde, Lisa Levin, Verena Tunnicliffe, Lenaick Menot, Rachel Boschen

Deep-sea mining is rapidly approaching the test-mining phase to prepare for commercial mining in multiple oceans, both in areas within and beyond national jurisdiction. The first test-mining operations are likely to focus on seafloor massive sulfides found at active and inactive hydrothermal vents within national jurisdictions – possibly in the coming months. Beyond national jurisdictions, the International Seabed Authority (ISA) is developing the regulations to oversee exploitation of polymetallic nodules, massive sulfides and cobalt crusts. The Deep Ocean Stewardship Initiative (DOSI) minerals working group has, over the last 3 years, made formal submissions on the regulatory framework, on the draft exploitation regulations, on the article 154 review of ISA and on the initial environmental regulations. In advance of both test and commercial mining, we urgently need to identify and develop comprehensive, ecosystem-based management practices for deep-ocean environments subject to mineral extraction. Transparent criteria for deep-sea institutional and corporate social responsibility also need to be established. Proactive development of management practices, frameworks and policy prior to the onset of mining will facilitate some degree of protection and preservation of the marine environment, whilst enabling the use of seabed mineral resources. The DOSI minerals working group constitutes a broad spectrum of scientific, industry, legal and policy expertise. We provide expert opinion, both in collated and individual response forms, on deep-sea mining related concerns to ISA and national bodies. Our publications and workshops on key concepts raise awareness and provide scientific updates on ecosystems targeted for mining. See http://www.dosiproject. org minerals working group and join us to further this work.

Jan 1, 2017

By Dallas L. Peck

The U.S. Geological Survey (USGS) recently completed phase 1 of a mapping effort that makes the United States the first nation to systematically acquire image maps of its underwater lands. In 1984, the USGS, as part of its mission to map and characterize the resources of the Federal lands, began a mapping effort in the newly proclaimed Exclusive Economic Zone (EEZ). The goal was to provide sonar image maps of this frontier area within 10 years. The mapping program is on schedule, with two-thirds of the EEZ sea floor, approximately 2 million square nautical miles, happed in 7 years. The deep water EEZ (depth greater than 200 m) around the 50 states is now complete except for the North Slope of Alaska, where ice precludes our surveying with a surface ship. Phase 2 of the EEZ mapping effort will begin in 1994, focusing on the American Flag islands of the western Pacific. Approximately 1 million square nautical miles of sea floor remain to be mapped around the islands.

Jan 1, 1992

By S. Rajendran

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

Jan 1, 1993

By 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 Roy Nilsen, Aravinda Perera

With the exponential growth of demand for minerals and need for diversification of supply channels, deep-sea mining is rapidly becoming inevitable. Productivity of underwater mining technology is salient to justify the deep-sea explorations. Methods for enhanced productivity of mobile mining equipment in a system level are investigated in this paper. Lessons learnt from the land-based mining has been the basis of this investigation. In general, mining productivity can be enhanced in two ways; firstly, by maximizing the amount of recovered material per unit time and secondly, by minimizing the cost of operation per unit material. Equipment that enable faster excavation, loading and transport in the seabed contributes significantly in increasing the amount of slurry per unit time. Improved mean time between failures (MTBF) of mining equipment will reduce the operational down time, thereby, contribute to maximize the amount of mined material per unit time. Several factors influence the operational cost minimization per ton of slurry. Higher efficient motor drive systems including the motor and PWM-fed inverter not only will save power but also will emit lesser heat thus the heat management can be less complex. This leads to more compact drive systems that allows higher power density, thus increased payload weight per empty vehicle weight. An energy storage method in the form of an utracapacitor in the electric drive system will also save the energy supply from the upstream.

Jan 1, 2018

Although Mn, Fe, Cu, Ni, and Co have been the main interests since the ferromanganese nodules had been found, the other major components such as Si and Ca might be very important controlling factors in the processing due to the locally variable content. It is because of the fact that SiO2 and CaO are added to decrease the smelting temperature in the reduction-smelting method for manganese nodule processing. We have compiled the 707 chemical data for KODOS (Korea Deep Ocean Survey) ferromanganese nodules, which have been acquired from 1994 to 2001 and have been also standardized from 2001 to 2003 to avoid the discrepancy between the data sets. All 707 chemical data were used for the hierarchical cluster analysis to get the elemental correlations and also classified by the morphological types. The averages from each station were classified by the facies groups (Fig. 1) and the localities. Then all data are plotted on the SiO2-CaO-MnO phase diagram at 1773°K to compare with the best compositional area in the nodule smelting. Variations and distributions of SiO2 and CaO as well as those of Mn, Fe, Cu, Ni and Co in KODOS ferromanganese nodules were also reviewed. The mineral phases assigned by the cluster analysis are CFA (Carbonate Fluorapatite), Fe-oxide, Al-silicate, and Mn-oxide. MnO contents are generally higher than SiO2 contents in most of the morphological types except for the Is- and It-type. The Dt- and Tt-type show wider range and the E-types show high anomaly in their CaO contents. The stations which belong to facies group A and B show generally higher MnO contents than SiO2 contents, however, the stations of facies group C and D show wide range in their MnO and SiO2 contents.

Jan 1, 2004

By S. Rajendran

Gas Hydrates (Methane Hydrates) are solid, ice ? like substances composed of water and natural gas. They occur naturally in areas of the world where methane and water can combine at appropriate conditions of temperature and pressure and are found in the ocean bottom sediments and in some permafrost areas. Besides temperature and pressure, factors like bathymetry, sediment thickness, sedimentation rates, and total organic carbon content (TOC) also control gas hydrate formation in the sea. The stability of gas hydrates depends on the critical high pressure ? low temperature combination (0-17 bars, 0-25ºC), which in turn dependent on the mix of gases from which the mineral is formed. As the critical parameters can be altered by deposition, erosion or slumping of sediments, formation or melting of ice cover, rise and fall of sea level and sudden temperature changes induced by tectonic activities, current flows or volcanisms, the gas hydrates tend to be very unstable. It is becoming increasingly evident that naturally occurring gas hydrates are significant component of the shallow geosphere and are of societal concern in at least three major ways: as an energy resource, a geologic hazard and a major contributor for climatic changes.

Jan 1, 2010