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By Steven D. Scott

Stephen D. Scott Steven Scott is a Professor of Geology, Director of the Marine Geology Research Laboratory and, until May 1997, was Chairman for 9 years of Geological and Mining Engineering, all at the University of Toronto. Steve also holds a cross appointment at the University of Western Brittany's European University Institute of the Sea in Brest, France. He was educated at the University of Western Ontario (B.Sc. and M.Sc.) and at Penn State (Ph.D.). Steve is a geologist/oceanographer specializing in base and precious metal massive sulfide deposits which he and his students have studied on five continents and on the bottom of three oceans. He was the first ore deposits geologist and first Canadian to witness "black smokers" on the ocean floor. Since 1982, he has participated on 21 oceanographic surface and submersible expeditions, many of them as Chief Scientist. His research team is currently carrying out projects in the W and NE Pacific Ocean. Steve has published more than 150 research papers and lectured in more than a dozen counties. Popularized accounts of his work have appeared in various media.. He has been honored by several awards and distinguished lectureships. Steve is President of the Canadian Scientific Submersible Facility, which operates the Canadian ROPOS robotic submersible, and is President of the International Marine Minerals Society.

Jan 1, 1998

By Jon Machin

?ORE? is defined as ?mineral/s that can be mined at a profit?. So, what is ORE at 2,000 m water depth? Is it 5% Copper or 1.8% Nickel/Cobalt? One of the key factors that determine what is ORE, profitable or not, is the cost of mining and extraction. Therefore a determination of ORE requires a commercial and technical appreciation of both sea bed mining equipment and mining options. Perry Slingsby Systems (PSS) have built more remotely operated submarine work vehicles, including 900HP trenching machines, than any other company. With Nautilus Minerals, PSS have been studying a range of deep ocean mining solutions. This paper discusses the commercial and technical issues of various extraction techniques applicable to deep ocean mining from 1,500 m to 5,000 m water depth. Issues such as the rate of extraction, (i.e. tons per hour) is a key economic component and is often constrained by the design and horsepower of the miner. Likewise the design itself of the mining machine and cutting heads can determine the size of material produced which impacts on methods of lifting the ore to surface. Issues such as overburden, sea floor conditions, style of mineralization and physical properties of the ore, obviously affect the selection of appropriate mining machine configuration.

Jan 1, 2004

By Steven D. Scott

A geologist can be likened to a medical pathologist trying to figure out from faint clues how something had lived and how it died, often long after the event. Present-day seafloor hydrothermalism has empowered geologists/pathologists to dissect a living system, in this case volcanogenic massive sulfides (vms) deposits of copper, zinc, lead, silver and gold. On the other hand, a considerable amount of our understanding of seafloor hydrothermal processes and its products stem from our knowledge, much of it from industry, of these same processes and products that formed ancient ores in oceans as much as 2700 million years ago and are now mined on land.

Aug 24, 2006

By Andrew Bellamy

A thorough appreciation of the origin, formation, preservation and geometry of marine sand and gravel deposits is central in demonstrating that their extraction by dredging does not affect coastal processes or marine life. Geological evaluation underpins wave, tidal and sediment transport modeling and assists in predicting the nature and extent of seabed change during and after dredging. Marine sand and gravel deposits in the English Channel, southern North Sea and parts of the Irish Sea are of predominantly periglacial fluvial origin and record long histories of valley and floodplain cut and fill associated with Quaternary climatic and sea level oscillations. In the Bristol Channel, the influence of marine transgression and tidal dominance in sorting proglacial outwash deposits is evident in the distribution of sandbanks, scoured channels and gravel lags of this region. These deposits are relict and are unrelated to coastal sediment dynamics. Their extraction leaves seabed depressions which monitoring shows remain unfilled. The resultant offshore bathymetric changes and sediment removal in over 10 m water depth are not transmitted to the coastal zone as beach drawdown, wave height increases or sediment starvation. Applications for new aggregate dredging permissions in UK waters must be accompanied by an EIA and need to make a convincing case that the dredging will not affect rare or declining species and communities of marine life. Seabed recovery rates post dredging are now investigated and understood with reference to geological setting and the uniqueness of the sediment/biological character (biotope). Investigation of the continental shelf by the Industry and others reveals the large extent of gravel-dominated biotopes relative to commercially viable deposits.

Jan 1, 2004

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

"Advancing our knowledge about trace metal distribution and abundance provides insight into formation, alteration, and trace element enrichment processes of ferromanganese nodules and crusts. A fundamental understanding of these mechanisms, in turn, has implications for the selective recovery of critical metals and the development of sustainable hydrometallurgical techniques. Synchrotron-based X-ray Fluorescence (SXRF) is a powerful, state-of-the-art analytical tool that can examine geochemical features of Fe-Mn nodules and crusts, such as abundance and distribution of trace elements, in an integrated and efficient manner. By correlating trace element composition and Mn oxidation states in these highly complex samples, it can be determined whether these parameters are related to the Mn oxide mineralogy (vacancy content of crystal lattice) and chemistry.In this study, eleven Fe-Mn nodule and crust samples from three circum-Australian locations – the South Tasman Rise, Lord Howe Rise, and Coral Sea – were analyzed at the Australian Synchrotron, Victoria, Australia. Micrometer-scale spatial resolution of geochemical features, such as concentric growth structures and element distribution, was achieved with high sensitivity (Fig. 1). For instance, Ni could be detected at 10's of ppm to 1 wt% levels. Information on other redox-sensitive trace elements, which are present at 10-1000 ppm levels (e.g., Cu, Co, Ti), were gained by means of fully quantitative elemental composition maps."

Jan 1, 2017

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 Yannick C. Beaudoin

Southern Explorer Ridge (SER) is an anomalously shallow, intermediate-rate spreading ridge located 200 kilometers off the west coast of Vancouver Island, Canada. It ranges in depth between 2600 m (deepest basins) and 1760 m (bathymetric minimum). At least 60 sulfide deposits are known to be associated with hydrothermal vent fields along the ridge. For the first time geological data, including deposit locations, collected from 15 marine expeditions to SER since 1983 have been assembled in a GIS format. GIS processing techniques were employed to plot the distribution of base metal concentrations for recovered sulfide samples. The highest base metal concentrations are found in the vicinity of the Magic Mountain site (main active vent field), and also proximal to a side scan sonar anomaly referred to as AGOR 171. Individual samples near these locations have yielded values as high as 29.3 wt\% Cu, 34.3 wt\% zinc, 0.97 wt\% Pb, 2.0 ppm gold, and 664 ppm silver. Sample paucity is the key limiting factor that prevents adequate assessment of the areas economic potential.

Jan 1, 2001

By Terence Day

The traditional approach to mineral resource development is to identify the resource and then to undertake an environmental impact assessment of the effects of developing the resource. However, the traditional approach tends to ignore or underestimate cumulative, indirect and synergistic effects (Therivel et al., 1992). Moreover, traditional environmental impact assessment puts the project proponent in a position where the environmental impact assessment is used to defend on environmental grounds, a decision which has already been taken on technical and economic grounds. An alternative approach is to undertake an area-wide or strategic environmental assessment, (United States Department of Housing and Urban Development, 1981; Kelly et al., 1987). Strategic environmental assessment consists of the compilation and analysis of environmental data and information on an area. The data and information includes physical and chemical oceanographic data, biological surveys, social and economic parameters such as recreation and resource use, and ecosystem stressors such as dumping areas and sewage outfalls. Strategic environmental assessment is being increasingly used in the U.S. to provide scientific information to evaluate national or regional objectives for development and conservation of coastal and oceanic resources (National Oceanic and Atmospheric Administration, 1991). The strategic environmental assessment process lends itself very well to an evaluation of offshore sand and gravel re- sources in Atlantic Canada, because although the potential resource is widespread, the environmental constraints on development are potentially serious, but highly variable. The approach has the merits of identifying areas which are least susceptible to environmental damage, and of concentrating the exploration efforts on that part of the resource which is most viable from the perspective of integrated resource management and marine conservation.

Jan 1, 1995

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 James E. Dailey

Marine mining is driven by profitability, and profitability is driven in turn by people and equipment that can work productively and safely at sea. Design challenges faced by the marine mining community have much in common with those faced by the offshore construction community. Technical solutions continue to move freely between both communities. A brief pictorial history summarizes the evolution of offshore construction technology as it grew in the Gulf of Mexico and expanded worldwide. Attention is focused on those areas of platform and pipeline construcion where there is potential technology application to underwater mining. An especially difficult challenge faced by both communities is work in the surf zone. Some innovative concepts for surf zone construction operations are presented and possible applications to marine mining are suggested.

Jan 1, 1989

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 B. Prause

Ferromanganese crust samples collected from Central Pacific sea-mount areas became of special interest after surprisingly high nobel metal contents have been analyzed. Hydrogenetic crust growth is controlled by the conditions of the oceanic water column. Thicker encrustations show two crust generations of different age ranges. The mean values of the chemical composition state that the older generation is richer in P, Ca, Ni, Cu, Zn, and Pt and depleted in Fe, Ti, Co, Al, and Si. The differences apparently indicate a distinct change of the geochemical environment. The Pt concentrations vary up to 1800 ppb and do not clearly correlate to one of the other metals. This might indicate a bond of multiple nature. Several mechanisms have been proposed to explain the Pt concentrations in ferromanganese samples. Our models consider seawater and cosmic spherules as responsible Pt sources. In seawater the main species of dissolved Pt probably exist as the doubly negatively charged tetrachloro-complex. A precipitation of Pt in seawater may take place if the chloro-complex is decomposed by reduction of pt2+ to pt0. On the other hand, the Mn02 precipitation is caused by an oxidation of Mn2+ which is supplied from the oxygen-minimum zone. The large activation energy needed for the oxidation of divalent ~n" in solution has been recognised, and the resulting slowness in the formation of Mn(V1)-oxihydrate sug

Jan 1, 1989

The seafloor occurrences of KODOS ferromanganese nodules can be classified into four facies based on the morphological types of nodules recovered and seafloor photographs. Facies A, B, and C are relatively unimodal whereas Facies D is bimodal in the size distribution of nodules. Both Facies A and B are highly covered by sediments, but Facies B is higher than facies A in nodule density. Facies C has a high density of small nodules and many traces of bioactivity. Facies D is irregular in nodule density, but occurs close to basement near scarps (Fig. 1). The transparent layer (TL) on subbottom profile records (von Stackelberg et al., 1987) is composed of three sedimentary units, which in cores are distinguished by color. The uppermost Unit I is postulated to be deposited during the past 0.21 Ma and the middle Unit II between 0.42 Ma and 0.21 Ma (MOMAF, 1997). There exists a hiatus between Unit II and Unit III. Unit III was deposited from 3.5 Ma to 1.5 Ma as determined by 10Be/9Be and/or 87Sr/86Sr dating (MOMAF, 2004). Internal textures observed on cut sections of nodules suggest four stages of nodule formation (Choi et al., 2000). The nuclei are either unbroken old nodules probably of hydrogenetic growth (1h and 2h) in Facies A and C, or nodule fragments probably of early diagenetic growth (2d) in Facies D, whereas there are both types in Facies B. The layers surrounding the hydrogenetic nodule nuclei are of hydrogenetic growth (3h and/or 4h) in Facies C, and are of early diagenetic growth (3d and/or 4d) in Facies A, B, and D. The layers surrounding the early diagenetic nodule fragments are mostly of early diagenetic growth (3d and 4d) in Facies A, B, and D. But hydrogenetic encrustations are also found as surface layers on the top in Facies B (Fig. 2).

Jan 1, 2005

By Graham Singleton

Around 235 million tonnes of marine aggregates have been dredged in the last decade from the UK continental shelf alone. The current distribution of marine aggregate production licence areas in North West Europe reflects the relationship between a variety of factors such as the natural distribution of deposits of sand and gravel, the demand for aggregates, the technical capabilities of the dredging fleet and environmental considerations. Whilst the sand and gravel deposits targeted by the marine aggregate industry are generally relict and therefore geographically fixed, the remaining factors have evolved over time and will continue to do so in future. Applications for new licences must not only reflect the current situation, but anticipate future trends. The main markets for marine aggregates are the construction industry, centred around the larger centres of population and coastal protection projects along the coastline of Europe. The aggregate industry as a whole does not create demand but simply meets it. Many factors influence the overall demand for aggregates and guidance exists for those in authority and industry who need to plan for the supply of aggregates. Adequate supplies should be maintained at the best balance of social, environmental and economic cost, whilst ensuring that extraction and development are consistent with the principles of sustainable development.

Jan 1, 2004

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 Georgy Cherkashov, Vladislav Kuznetsov

The presentation describes new data concerning the age of the Mid-Atlantic Ridge (MAR) hydrothermal fields. The collection of massive sulfides recovered from six hydrothermal fields has been dated using the 230Th/U method. The range of the data obtained is rather wide: from 2.2 up to 65.1 thousand years BP. Three stages of hydrothermal activity were detected for this 65 Kyr period of geological evolution: modern (0 -5), 20-25 and 58–65 thousand BP (Figure 1). This conclusion was confirmed by dating the associated metalliferous sediment layers which also indicate the hydrothermal events led to the formation of sulfide mineralization. There is a correlation between the age and size of massive sulfide deposits: older deposits are larger (Table 1). This and other applications of obtained data will be discussed in presentation.

Aug 24, 2006

By Michael W. Milner

Cold Ocean Placers: Polar storms, interstadial littorals and crustal adjustments. Polar storms with consistent strong winds in the Southern, Antarctic Ocean are responsible for placer deposits on both the east and west coasts of Australia, on the west coast of New Zealand, as well as on the coasts of South America and Africa. Arctic winds, confined by both land and ice, generate similar placers in Labrador and Greenland as well as on the coasts of Scotland, Norway, Hudson's Bay, Nome, Goodnews Bay, Kamchatka and the north coast of Siberia. Tasman and Labrador seas have several parallels to Newfoundland, including north-south polar waterways, young spreading ocean floors, and youthful coastal escarpments with glaciated coasts. Black sand beds in beach deposits on the modern and Pleistocene transgression strandlines, skewed to the distal ends of beaches, and set into either bedrock or sediment fill, are the locus of the light-heavy mineral placers with titanium, zirconium and rare earth elements; chromium; iron; and tin. Gold and platinum group elements are the ultra heavy minerals at one end of the spectrum and tend occur in proximal placers generated, either directly from bedrock sources, or as minor by-products in distal light-heavy mineral placers. Diamonds are unusual in that the value is only in the larger stones, despite the formation of beach sand and aeolian placers in the littoral zone, and the sites of concentration are in very high energy bedrock traps, on terraces that are mined to depths of 100 metres below sealevel.

Jan 1, 1995

By J. C. Wiltshire

Both ferromanganese crusts and nodules present potential processors with enormous volumes of tailings of dubious environmental character: most processing scenarios fail to utilize the uneconomic manganese itself, leaving a total waste volume on the order of 96% of the incoming ore. Each current disposal proposal seems flawed: (1) backhauling to the initial mine site is costly and might run afoul of EPA or UN marine dumping*regulations, (2) subsea disposal near a coastal processing site means almost inevitable community opposition, (3) agricultural soil amendment for improving barren lava or coral rubble appears to require prohibitive amounts of supplementary phosphate, and (4) the slag resulting from an energy intensive pyrometallurgical processing may have potential as road ballast, but few processors will opt for smelting in all but those locales where energy is very cheap. This unfortunately rules out a smelting operation in almost any Pacific Island environment. We envision at least one other scenario which could result in both the removal of tailings from a processing plant and an increase in the supply of useful building materials at little or no cost to either the processing or construction industries--transforming a tenacious waste into a novel resource. Ongoing experiments have demonstrated considerable potential for turning acid leach tailings into dark composite facing stone, fancy black tile, novelty ceramics or concrete aggregate. The tailings are commonly very fine grained and may also serve as an additive in drilling mud. Applications as an additive to asphalt also need to be explored. The metal scavenging nature of ferromanganese minerals should be considered as a radioactive waste disposal matrix. There is no doubt that the greatest challenge will be

Jan 1, 1991

A C-CORE study on behalf of the government of Newfoundland identified the inner continental shelf off northeast Newfoundland as having a relatively higher potential for hosting placer gold than other parts of the inner shelf. Under the auspices of the Canada-Newfoundland Cooperation Agreement on Mineral Development, the Geological Survey of Canada conducted a three-year project to map the distribution of surficial sediments and the abundance of placer minerals (particularly gold) from White Bay to Cape Freels. Much of the study area is a fjord coast, with steep rocky slopes and scattered gravel beaches. The extreme east, from Hamilton Sound to Cape Freels, has a wide, shallow inner shelf, sandy beaches, and extensive coastal dunes. Relative sea level was high in the late glacial period. It has fallen continuously in the west, but in the east it dropped to -19 m, before rising to within several metres of the present level by 3 ka. In terms of surficial sediments and processes, five zones are identified: (1) Deep offshore deep basins that contain thick postglacial mud overlying glacialmarine gravelly sandy mud. This zone is below a depth of 370 m in White Bay, 300 m in the Notre Dame Basin. 2) Basin transition zone in which the sea bed has been eroded by currents, so that glacialmarine sediments are exposed in places. Winnowing has formed an uppermost layer of muddy gravel. There is a slight potential for enhanced levels of fine particulate gold, but the gold would not be exploitable. (3) Iceberg impacted zone Above 200 m the keels of icebergs impact the sea bed, causing furrowing and pitting. Furrows predominate in deeper areas, and pits are concentrated at the inner boundary of this zone. Iceberg turbates have developed in shallow waters (60-100 m). Combined with winnowing, iceberg turbation could enhance the potential for concentration of fine particulate gold, but not into economic quantities. 4) Wave dominated zone Above approximately 60 m the sea-bed sediments are highly mobile due to waves, currents, and iceberg impact. Sand is either rippled or organised into sand waves. Gravel is either poorly sorted, and organised into

Jan 1, 1995

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