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By Mark D. Hannington

Seafloor polymetallic sulfides have been found in diverse volcanic and tectonic settings on the ocean floor at water depths ranging from 3700 meters to <1500 meters. More than 100 occurrences of hydrothermal mineralization have been documented (including Fe-oxide deposits, Mn-crusts, metalliferous sediments, and massive sulfides), but high-temperature hydrothermal activity and large accumulations of polymetallic sulfides are known at fewer than 20 different sites. Chemical analyses of samples from these deposits indicate that they contain important concentrations of Cu, Zn, Ag, and Au, comparable to those of massive sulfide deposits on land. However, the lack of sufficient data concerning the distribution, size, and bulk composition of seafloor deposits precludes a meaningful assessment of their resource potential.

Jan 1, 1994

By T. E. Sedysheva

The study of Co-rich manganese crusts has reached the level which allows to start prospecting works in the observable future, and furthermore, probably, exploitation of ore deposits. In this connection, among other goals, the necessity to analyze a distribution of ore bed parameters in details is quite urgent. Foremost, these are crust thicknesses in connection with landforms and elements of submarine mountains relief. This report is based on representative sampling made in course of research cruises run by SSC Yuzhmorgeologiya over guyots of the Magellan Seamounts. Crustal covers could overlie seafloor surfaces which are confined to a various landforms and elements of relief under the condition, that they are free of sediments. These are planed parts of a summit surfaces, edges, spurs, rectilinear parts of slopes, intermountain saddles and volcanic edifices. It is known, that crustal thicknesses are different at a various forms of relief [1]. We processed statistically the data around crustal thicknesses, which were sampled by dredging and submersible drilling (Tables 1, 2).

Jan 1, 2010

By Kris van Nijen

IHC Merwede, a Dutch supplier of ships and equipment for dredging and mining activities, and DEME, a Belgian dredging and environmental services group, will enter into a joint venture for deep-sea mining activities. Under their cooperative agreement, IHC Merwede will be responsible for the development and construction of technical solutions, while DEME will be responsible for operations. Together the companies will offer a unique pioneering total solution. The joint venture will be known as OceanflORE.

Jan 1, 2011

By Julian Malnic

The emerging marine minerals exploration and mining industry is currently focused mainly on the technical elements for its success such as developing exploration and mining technologies. However, in one sense, the technical challenges are quite soluble whereas those arising in the fields of the environment and public opinion could present this new generation of miners with problems that are far more difficult to overcome. One need only look at the issues currently faced by mining projects on land to see how powerful the new forces of so-called ?civil society? are in stopping mineral developments in many countries. From the geographic viewpoint, there are many countries but there is just one ocean, so the impacts experienced by any one operation are likely to have pervasive repercussions throughout the industry. A well-oiled NGO development protest lobby will see leverage in resisting this new industry and will seize on the single-ocean angle. The Australian Minerals Industry has established a voluntary Code for Environmental Management that provides an active and valuable model for satisfying the ?court of public opinion? and in delivering economic results to industry that are in current jargon, sustainable. An explanation of the Code for Environmental Management, and the reasons behind 44 companies representing more than 300 operations and 85% of Australia?s sizeable mineral production being signatory to it will be given. Participants see it as a means to future shareholder wealth.

Jan 1, 2000

By Irina A. Pulyaeva

Hydrogenetic Fe-Mn crusts are ubiquitous in the ocean basins and play an important role in marine mineral-deposit research because of their widespread occurrence and high concentrations of valuable and rare metals. Directed research, which started in the last quarter of the 20th century, has provided significant results, with substantial amounts of data produced on Fe-Mn crusts structure, composition, and distribution in the global ocean. Detailed study of several seamounts has given confidence about the scale of Fe-Mn crust development and their characteristics. Now, commercial interests gain more and more attention. However, at the same time some theoretical questions related to Fe-Mn crust history including controls on metal sources and concentrations have not yet been answered. Here, we present the overview of age, composition, distribution, and geological setting of hydrogenetic Fe-Mn crusts from Pacific and Atlantic seamounts and discuss the geological evolution and conditions that led to the formation of potentially economic concentrations of metals. The age, composition, and distribution of Fe-Mn crusts in the Atlantic and Pacific oceans were determined by using a Fe-Mn deposits database compiled from our original data, published papers, published databases, and other international sources. Comparative analysis of Fe-Mn deposits from the Atlantic and Pacific oceans shows that there are similarities in basic characteristics of crust formation in both oceans. Simultaneously, there are significant differences in the scale of Fe-Mn crust distribution and composition that can be explained by differences in geological settings and characteristics of the deposition environment.

Jan 1, 2011

By Gary J. Massoth

Are hydrothermal emissions from subduction-related volcanic arcs important to the total hydrothermal burden of the oceans? While historical observations of hydrothermal venting of fluids at mid-ocean ridgecrests, intra-plate hotspots, and backarc spreading centers are numerous, we remain poorly informed regarding the contributions from hydrothermal systems associated with oceanic submarine arcs. Here we report the chemical results from the first systematic assessment for hydrothermal activity at an intra-oceanic arc front. We discovered that 7 of the 13 submarine volcanoes that define a 260-km-long segment of the southern Kermadec arc north of New Zealand are hydrothermally active. Most significant here is that the chemical compositions of the various hydrothermal systems, inferred from back-extrapolation of observations of hydrothermal plumes, are diverse, and in many instances enriched in the concentrations of gases (e.g., CO2 and H2S) and metals (e.g., Fe and Mn) compared to effluents commonly discharged from mid-ocean ridges. If our results are generally representative of submarine arcs, whose global extent may equal one-third that of ridgecrests, the answer to our leading question could be a resounding yes in terms of both volume and chemical composition.

Jan 1, 2001

By Richard H. T. Garnett

The Chilean part of the archipelago of Tierra del Fuego, situated south of latitude 62o S, is within that country?s Región de Magallanes y Antártica, and separated from the remainder of Chile by the Magellan Strait. In recent geological history several phases of Quaternary age glaciers originating in the Andean and Dawinian Cordilleras eroded assumed primary gold deposits and entrained their related alluvial deposits. Piedmont glaciation extended to the east and south over m0st of the land and beyond the present-day coastline into extensive areas exposed during the resulting lowered relative sea level. During interglacials particulate gold incorporated unevenly in the widespread drift, till and moraines was fluvially released and concentrated into streams and flood gravels. Coastal erosion enriched various beaches with gold. From 1868 onwards Tierra del Fuego hosted a major gold rush whereby early, labour intensive, beach mining eventually developed into inland dredging. But continued mining activity was interrupted and then terminated by several external factors. Most miners, always seeking ?greener pastures?, joined the rush to the new discoveries in the Klondike (1896) and Nome, Alaska (1899). In 1904 the international boundary, established in 1881, became the subject of a major dispute not settled until 1984, The Panama canal?s opening in 1914 turned Tierra del Fuego, previously on the Pacific-Atlantic shipping route, into a remote backwater. World War II brought opposing foreign naval forces to the actual islands where most gold had been taken from the beaches. It also crippled the dredging industry which lost its coal supply and never recovered. Nevertheless, some small scale mining continues to this day.

Sep 14, 2011

By Justin C. I. Baulch

In October 2004 Placer Dome entered into an exploration farm-in agreement with Nautilus Minerals, to explore for Submarine Massive Sulphide (SMS) deposits on Nautilus? PNG exploration tenements. Placer/Nautilus currently holds approximately 15,000 km2 of tenements in PNG waters, either granted or under application, covering all reported seafloor hydrothermal vent occurrences.

Jan 1, 2005

By Gale L. Hubred

Kennecott?s Ledgemont Laboratory developed the Cuprion Process to recover metal values from manganese nodules in the early 1970s. A reducing leach of monovalent cuprous ion attacks the manganese oxide matrix, converting the manganese dioxide to manganese carbonate and releasing the copper, nickel, cobalt, and zinc as ammine complexes. Cuprous ion is generated by contacting leach liquor with carbon monoxide. Copper, and nickel, are recovered by solvent extraction and electrowinning. Cobalt is precipitated as cobalt sulfide and recovered as cobalt powder. Manganese, molybdenum, and zinc can be recovered optionally but have not been included in this process. Kennecott authors have described aspects of the process, but the Cuprion process has not been revealed except in patents. Tables are included for capital and operating costs and revenue. Even though economic recovery of nodules is not anticipated in the foreseeable future, some of the process steps may have application in other places. The Ledgemont Laboratory was a unique operation we think worth documenting. The report is based upon work done up until the mid 1970s. The report represents the work of the entire Kennecott nodule team. It is this author?s intention to save this result and credit the work of that nodule team. The paper is dedicated to the memory of Dr. Herbert Barner, a key member of the team who died in 2003.

Jan 1, 2005

By Mark Vardy, Kasia-Leigh Chidlow, Tim Minshull, Jeorg Bialas, Sven Peterson, Bramley Murton, Alba Gil

Since the discovery of the first black smoker on the East Pacific Rise in 1977 (Francheteau, et al., 1979), the hydrothermal vents, now called seafloor massive sulphides (SMS) deposits, have generated great interest in the geological community, especially regarding their formation and composition. SMS deposits are areas of hard substratum, with high base metal and sulphides content, that form through hydrothermal circulation and are commonly found at hydrothermal vent sites. The high base metal (Fe, Cu, Zn, Pb), sulphur-rich mineral content has interested mining companies, due to their potentially high economic value. Currently, the known SMS deposits do not have the same dimensions as the massive sulphides (MS) found on land (covering just 10s to 100s m2) and pose significant mining challenges (being located in water depths between 800 m and 6000 m), meaning that they do not appear to be economically exploitable at present. However, these deep-sea mineral resources could be important targets in the near future, particularly with our ever-increasing demand for base metals. A key aim of the European Union-funded Blue Mining project is to develop techniques to robustly quantify SMS deposits dimensions (both surface expression and subsurface extent) and therefore assessing the suitability of SMS deposits for future economically viable and environmentally clean deep-sea mining operations.

Jan 1, 2017

By Derek V. Ellis

This article is a summary, with documentation and references, of recent global developments in identifying environmental issues affecting the marine mining industry. It is recognised that marine mining for various products occurs at various depths from shallow water (e.g. aggregate and diamond mining) potentially to great depths (e.g. metalliferous muds, and manganese crusts and nodules). Nevertheless there are environmental issues in common, even though the options for resolutions will vary greatly. The point of this review is to identify the issues, so that where site-specific resolutions are considered, it is possible to draw on experience with the issues elsewhere. Related mining issues, e.g. tailings effluent quality, orebody geochemistry, are mentioned where relevant but are not detailed in this article, although obviously they are a part of there solutions to the environmental issues. The environmental issues and their resolutions are important - on the basis of the ethic of not creating more impact than is inevitable, and the long-term financial and social costs at a mine-site of not getting the resolutions right.

Jan 1, 2000

By Philomene Verlaan

This study examines the possible relationships between compositional variability in non-hydrothermal manganese nodules and large-scale environmental parameters. In the central SW Pacific (145-180° W and 20-O° S) the level of primary productivity, the rates and proportions of carbonate, silica and organic matter supply to the sediments, and the position of the seafloor relative to the Calcium Carbonate Compensation Depth (CCD) appear to directly influence nodule composition. Four zones of nodule composition are apparent. These zones correlate fairly well with the level of primary productivity in surface waters, as estimated by satellite-based measurement of chlorophyll content. The observed correlations between surface productivity and nodule composition are consistent with the contention that the dominant source of several transition metals in these deposits (i.e , Mn, Ni, Cu. and Zn) is provided by removal of fine-grained particulate matter from the water column by biological means. Subsequent decay of organic matter in sediments augments the content of these metals in the nodules through oxic and sub-oxic diagenesis. The opposite behavior of Fe and Co content may in part result from mineralogical and dilution effects.

Jan 1, 2000

By Nobuyuki Okamoto

The 21-year long-term Japan-SOPAC Cooperative Deep-sea Mineral Resources Study Programme was completed in March 2006. The Programme, which commenced in 1985, has seen numerous marine research surveys being conducted within the Exclusive Economic Zones (EEZs) of 12 SOPAC member countries (Figure 1). The various research and government institutions that have been closely involved in this longstanding Programme include: the Japan International Cooperation Agency (JICA); Japan Oil, Gas and Metals National Corporation (JOGMEC) (formerly, the Metal Mining Agency of Japan, MMAJ) and relevant ministries of the participating Pacific Island governments.

Sep 24, 2006

By Sang-Mook Lee

The Manus back-arc basin behind the New Britain Trench is one of the major sites of active seafloor hydrothermal vent-fields which are considered to be modern-day analogue of felsic volcanic-hosted polymetallic massive sulfide deposits abundant in ancient geological record. Many of these deposits represent multi-million dollar resources, and yet very little are known about the fundamental processes leading to their formation. In November 2000 January 2001, the PACMANUS hydrothermal system in this region will be targeted by the Ocean Drilling Program Leg 193 to investigate the internal anatomy. A number of observations that suggest that the tectonic, magmatic and hydrothermal processes in the eastern Manus basin spreading center are unusual in that they can not be explained by a simple back-arc opening due to subduction of the New Britain Trench. Geochemistry of submarine volcanoes in the eastern Manus basin, for instance, shows affinity to arc rather than back-arc type volcanoes. Yet these submarine volcanoes lie too faraway from the Benioff-Wadati zone. One hypothesis is that the magmatic and subsequent hydrothermal activity of this region is a direct result of the irregularities in the deep crust and upper mantle structure and that the tectonic process is controlled by the sharp inflection of the New Britain Trench. According to this hypothesis, the two major southeast-trending strike-slip faults in the eastern Manus Basin, Djaul and Weitin Faults, should extend farther down and join to the New Britain Trench. They would form a transform arm of the triple junction with the New Britain Trench southeast of New Britain Island and southwest of Bougainville Island forming the other two arms. A trench-trench-transform triple junction can not be stable over time, and therefore a slight change in the plate velocity may lead to a dramatic change in the configuration of the plate boundaries. If so, the instability of the triple junction may cause large tectonic deformations, such as mantle uplift under the Manus basin due to mantle rupturing by transform faults, and therefore may explain the arc-style volcanism and unusual compositions of hydrothermal deposits in the eastern Manus basin.

Jan 1, 2000

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 Gérald Riverin

Over the past century, exploration methods for volcanogenic massive sulphide deposits have evolved in response to a decreasing number of discoveries made by traditional surface prospecting and by ground and airborne geophysics. Statistical trends support the concept that fewer and fewer outcropping and sub-cropping VMS discoveries will be made in the future. In turn, this creates new opportunities to develop more sophisticated exploration models and techniques to explore at greater depth and to make blind discoveries. Current exploration models include various combinations of geological, geochemical and geophysical criteria which have been based on the results of land-based VMS research. The role of seafloor research in the development of these models has so far been only of a subordinate nature, perhaps due to a lack of direct involvment of the exploration industry in the seafloor research, and vice-versa for the seafloor researchers in VMS exploration. Another contributing factor is that exploration relies on exploration criteria that result from detailed geological, geochemical and geophysical studies of both footwall and hanging wall rocks, studies that are not possible in modern sea floor environments. Nevertheless, seafoor research has contributed to our understanding of the growth of sulphide mounds, the mechanism of sulphide deposition and of the chemistry of fluids involved in VMS systems. In particular, the role of structure and of tectonic setting has been clarified through observation of active seafloor hydrothermal systems. In turn, observations made in land-based VMS research has helped seafloor researchers to focus on key issues which, will eventually contribute to improved exploration models.

Jan 1, 1998

By Robert G. Ditchburn

The NW caldera hydrothermal vent field at Brothers volcano, of the Kermadec-Tonga arc, has associated massive sulfide mineralization. This includes an abundance of black smoker chimneys that contain significant concentrations of copper, lead, zinc and gold (de Ronde et al., 2005; de Ronde et al, 2010, under review). [ ] The oldest volcanic massive sulphide (VMS) samples recovered so far from Brothers have been dated using radiometric methods at GNS Science and found to be c. 1000 years old. By contrast, a volcanic cone that has formed in the southern part of the caldera has no associated VMS. Only elemental sulphur and Fe-oxide crusts are present here, samples of which have been analysed for their trace elements. From d34S values of sulfates and native sulfur, and the volume of gas (dominated by CO2 and H2S) discharging at the cone site, elements being deposited here are considered more directly magmatic in origin (de Ronde et al., 2005; 2010 under review). It has been discovered that deep-seated changes in volcanic activity at Brothers affect the NW caldera and cone site simultaneously, though the mineralogy at each site is so very different. Thus, the cone site is being studied to determine if elements being deposited there can be used as predictors of potential future VMS mineralisation as similar sites have been found at other volcanoes along the Kermadec arc and elsewhere. The frequency of these deep-seated magmatic events is considered important in the formation of Cu-Au-rich mineralization along arcs. The analysis of Fe within resulting hydrothermal plumes (surveyed by surface vessels), and trace elements in rock and mineral samples, are used to help determine the influence of magmatic contributions to the hydrothermal system. To verify that plumes are a reliable proxy for hydrothermal events depositing iron on the seafloor, Fe-oxide crusts from Brothers volcano cone have been dated to see if their emplacement coincides with highly Fe-enriched plumes in the water column. The radiometric dating techniques developed for barite-rich VMS, i.e. using 228Ra and 226Ra, were unsuitable for the Fe-oxide crusts because 210Pb was the only isotope detected by gamma spectrometry. Therefore, new techniques using 210Pb, 10Be and arsenic have been established.

Jan 1, 2010

By C. R. Pearce, B. Murton, S. Howarth, P. Lusty

"With the expansion of “green” energy technologies, the demand for the critical raw materials required to sustain this growth is increasing. Many E-tech elements, including tellurium (Te) and rare earth elements (REEs), suffer from high supply shortage risk and the need for more diversified metal supply routes is driving research into alternative resources. Hydrogenetic ferromanganese crusts, seafloor deposits of Fe- and Mnoxyhydroxides that form from the direct precipitation from seawater, present a potentially important future source of E-tech elements. With growing interest in the potential wealth of these deposits and the issuing of permits for deep-sea mining and exploration, more work is underway to understand the nature of ferromanganese crust deposits, their elemental concentrations and distributions, and the potential impacts of mining activities.This research focusses on the formation of ferromanganese crust deposits and processes that control the extreme enrichment of elements such as Te, Co and REEs. The crusts were systematically sampled and mapped between ~ 1000 – 4000 m depths using ROV ISIS, from a range of environments, substrates and morphologies from Tropic Seamount (NE Atlantic) in order to determine the seamount-scale factors that control major and trace elemental concentration variations. These factors include depth, surface roughness and micro-bathymetry, location relative to long-term mean current direction and energy, influence of tidal energy dispersion across the seamount, sediment supply, substrate lithology, biological productivity and phosphatisation. The study analyses trace-element characteristics of 100 ferromanganese crust samples alongside standard reference materials NOD-A-1 and NOD-P-1 (US Geological Survey manganese nodules). At this initial stage, we report results from whole rock acid digestion and ICP-MS analyses."

Jan 1, 2017

By Alexander Malahoff

The study of why and how life survives in the Extreme environment is a major frontier of science today. Extremophiles are organisms that require extreme environment including high temperature, pH, pressure and salt concentration, or low temperature, pH, nutrient concentration, or water availability. Their common habitats are geothermal vents, pools, lakes and craters of active volcanic regions, such as those of New Zealand, Japan, Kamchatka, Yellowstone USA or the hydrothermal vents of the ocean ridges and submarine volcanoes. These settings are accessible by foot, boat, helicopter, or submersibles. This presentation examines the geology, chemistry of geothermal sites of New Zealand, including the active volcano, White Island, Yellowstone, the submarine volcano Loihi in Hawaii, and sections of the mid-ocean ridges. Designing process and construction of Extremophilic sampling and bioreactor systems used in the study of Extremophiles will be discussed. The driving force behind the research of extremophiles is not only the fundamental science, but also biotechnological potential associated with these microorganisms and their cellular products. The University of Hawaii?s Marine Bioproducts and Engineering Center (MarBEC) is laying the foundations for such new industries.

Jan 1, 2001

By Sven Petersen, Berit Lehrmann, Bramley J. Murton, Paul A. J. Lusty

"INTRODUCTIONToday’s metal mining focusses on land based ore deposits which only consider one third of the Earth’s surface. Through an increasing global demand of strategic metals used in the electronic and green industry (Zepf et al. 2014), ‘uneconomic’ sites of lower grade in more technical challenging grounds such as greater depth and/or more remote areas are developed by the mining industry often resulting in higher environmental impact. However, considering the steady growth of the Earth population a shortage of certain metals may occur (Krausmann et al. 2009). In 2010, the United Nations allowed commercial exploration for seafloor massive sulphides (SMS) in international waters with currently six contractor licenses being granted.Although the number of discovered vent sites has steadily increased since the first discovery of hydrothermal venting at the Galapagos Rift in 1977 (Corliss et al. 1979) with more than 600 sites being known today, their economic potential is poorly constrained. So far Nautilus Minerals Inc., a Canadian mining company, is the only company having conducted a NI 43-101 resource estimate for the Solwara site, located in the territorial waters of Papua New Guinea. Other studies using bulk geochemical data from 95 sites published in literature do exist (Hannington et al. 2011, Monecke et al. 2016) suggesting a global resource potential for today’s known SMS deposits of 600 million tons with a median grade of 3 wt.-% copper, 9 wt.-% zinc, 2 g/t gold and 100 g/t silver. However, the geochemical data being used originated mainly from easily recoverable, mainly non insitu surface grab-samples and are under current mineral resource classification schemes such as JORC code or NI 43-101 not even accepted for resource estimations. Furthermore surface samples such as high-temperature sulphide chimney and talus material are not representative for the entire deposits with information regards thickness and continuity of individual sulphide layers obtained through drilling being scarce. In addition, it remains unknown what geological processes occur once hydrothermal activity ceases and whether metal tenor becomes enriched, depleted or disappears."

Jan 1, 2017