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By Kokichi Iizasa

Kuroko-type deposits exist in Japanese EEZ. Some of them are present in the Izu-Ogasawara oceanic island arc south of Tokyo. Major two Kuroko-type deposits occur in the area. One is the Sunrise hydrothermal field occurring on the caldera floor of Myojin knoll, which is likely to be the developed stage in sulfide mineralization. Another is present in the crater of Suiyo seamount that is the early stage of sulfide mineralization. The two deposits are here presented on the growth history based on samples recovered by Benthic Multicoring System (BMS).

Jan 1, 2002

By David Heydon

The big money is backing both manganese nodules and manganese crusts as the most likely deep ocean mining development by 2010, but seafloor massive sulphides of copper/gold/zinc offer an alternative bet for a start-up by 2010. A study of the ?form guide? or comparison of these resources provides direction on which resources are economic candidates for commercial deep ocean mining development by 2010. This paper covers the commercial and technical issues of exploration, resource definition, drilling/sampling, sea bed mining options, mine plans, environmental issues, legal tenure and capital and operating costs (i.e., profitability) of these two mineral types. Nautilus Minerals has just completed a pre-feasibility engineering study of mining sea floor massive copper/gold/zinc sulphides at 2,000 m depth. The Nautilus study reviewed a range of mining and lifting options, settling on tracked continuous drum cutter miners to produce 2 million tons per annum of high grade ore. Capital costs are shown to be at least 30% lower than a land based copper mine of the same production capacity. Likewise 75% of world?s copper would be produced at a higher operating cost that the proposed seafloor mine. This paper then draws on the Nautilus study for comparison with earlier feasibility studies by others on manganese nodule mining to predict the likely directions in deep ocean mining to 2010.

Jan 1, 2004

By Dwight D. Trueblood

The Benthic Impact Experiment (BIE) is designed to address the effects of sediment redeposition prior to the commencement of commercial mining. The experiment is being conducted in collaboration with Russian scientists from the Yuzhmorgeologiya Association aboard the R/V YUZHMORGEOLOGIYA. Sediment resuspension and subsequent redeposition during manganese-nodule mining is predicted to be one of the primary impacts on benthic communities living on the abyssal seafloor. The redeposition thicknesses that will cause significant faunal mortality in the deep sea are unknown. Sediment redeposition could adversely affect abyssal benthic communities through entombment, or through starvation caused by food dilution and obstructed feeding. This spring NOAA conducted the main portion of the BIE experiment, blanketing the experimental area with varying thicknesses of sediment using the Deep Sea Sediment Resuspension System (DSSRS). The DSSRS was conceived by NOAA scientists, designed and built by Williamson and Associates, and is the critical piece of equipment used to generate the controlled sediment redeposition environment on the 4800-m deep abyssal plane. The DSSRS consists of an 1800-kg sled, 4.8 m long, 2.4 m wide, and 2.2 m high. The sled was towed and powered using an 8,000-m, 26-mm single conductor cable having a 3,000 VAC capacity. As the sled was towed across the bottom, mud was ingested through two rear-facing, 45-cm wide intakes using two 7.6-horsepower pumps, and discharged 10 to 20 m above the bottom through two 20-cm diameter riser hoses. Each pump was instrumented with optical backscatter sensors providing real-time information about the discharge concentration.

Jan 1, 1992

By Ivar Eskerud Smith, Ole Jørgen Nydal, Niranjan Reddy Challabotla, Svein Sævik

INTRODUCTION Airlift pumping, utilize compressed air that is injected at the bottom of a vertical pipe submerged in the water, reduces the mixture density inside the pipe and lifts the liquid or mixture of liquid and solids. This type of pumping technology, which is simple and without moving parts submerged in water, which provides several advantages compared to the mechanical pumping. Airlift is used in various difficult pumping applications such as transport of fluids corrosive to metals, explosives, nuclear and toxic materials in chemical industries, diamond mining and coal transport. Application of airlift to deep sea mining conditions was investigated by extensive laboratory experiments [1], theoretical analysis [2], and limited proof of concept field studies [3] starting in 1970’s with the discovery of huge amounts of manganese nodules discovered on the seabed at a depth of ranging from 4000 to 6000 m . Even after extensive investigations over the last five decades, there exists no commercial application of airlift technology for lifting of minerals. The major problems with the application airlift for deep ocean mining was (a) lack of control over the expansion of the injected gas, which increases the velocity in upper part of the riser pipe (b) lower efficiency compared to mechanical pumping [3]. Different flow regimes are encountered in airlift pumping: bubble, slug, churn and annular flow. Annular flow regime is the least efficient in lifting of particles and churn flow has better efficiency [3].

Jan 1, 2018

By Hunsoo Choi, Sang-Mo Koh

Manganese nodule, the aggregate of fine grained manganese oxide minerals, is very brittle and fragile. In exploitation of manganese nodule, manganese nodules are easily broken into small pieces or powder during collecting and lifting from the sea floor. The broken manganese nodule under few millimeters and bottom sediment pumped up with manganese nodule affect to the lifting process. In this study, we tried to understand the physical properties of the powdered manganese nodule and bottom sediment, and to know the effect which may be rised to the actual mining of manganese nodules.

By Siân E. Boyd

Studies of benthic recolonization in the aftermath of marine aggregate dredging in the U.K. and elsewhere are limited and are largely confined to experimental circumstances. Investigations of the physical and biological status of licensed extraction sites in the U.K. at various times following cessation of commercial dredging are very limited, and so judgments as to the likely progress towards environmental restoration and the time-scales involved continue to be based on predictions rather than real data. This field-based research programme was commissioned to enhance the understanding of processes leading to physical and biological recovery of the seabed following dredging, thereby aiding the identification of practices to minimize environmental harm at licensed sites, and to promote rehabilitation on cessation. The outcome of survey work will have the notable benefit of allowing questions about the present status of locations hitherto subject to commercial exploitation to be answered directly, rather than by inference.

Jan 1, 2002

By David M. Holmes-Smith

Many attempts have been made to design and build an AUV that is small, meets the sensing objectives and is cost effective. Many inventors have already designed smaller vehicles but the problem observed is an increased vehicle instability resulting in instrument instability where data gathered is not trustworthy. Additional problems include instrument weight to vehicle weight ratios and the lack of space for power storage and electrical components. The UFOceanic seeks to remedy these concerns by employing a completely different design and propulsion system. Still in the design stage ? now with a mock-up unit for testing, the results are encouraging. We have chosen a very low voltage embedded systems design using multiple PIC processors and fuzzy logic programming. We are designing the craft to rotate for stability and to provide friction reduction to minimize the need for instrument stability compensation and propulsion power. Additionally, we are looking and experimenting with a number of power plant drive systems including flywheels, GNP (plasma), fuel cells and more conventional systems. We of course plan for the UFOceanic to run for months at a time supported by a self-charging system.

Jan 1, 2001

By J. R. Hein

East Diamante is a submarine volcano in the southern Mariana arc that is a complex caldera about 10 km x 5 km (elongated ENE-WSW), and breached on its northern and southwestern sectors. A large field of barite-sulfide mounds was discovered in June 2009 and revisited in July 2010 aboard the R.V. Natsushima using the Hyper-dolphin ROV. The mound field occurs on the NE flank of a cluster of resurgent domes inside the caldera. The mound field extends for more than 100 m long and is about 30 m wide, and is aligned along a NE-SW rift valley. A sample of dacite yielded a 40Ar/39Ar age of 20,000±400 years. Individual mounds are typically 1-3 m tall and 0.5-2 m wide, with lengths from about 3 to more than 5 m. The mounds are composed of barite-dominant layers interbedded with Zn-sulfide-rich barite layers. Rare inactive spires and chimneys cap some mounds. Fe and Mn oxides are currently forming small (<1 m diameter, ~0.5 m tall) subsidiary mounds on the top of some of the sulfate/sulfide mounds and drape the flanks of others. Both diffuse- and focused-flow fluids emanate from the subsidiary oxide mounds. Ages of the basal sulfate/sulfide mounds cluster around 4,000 years old based on 226Ba/Ba, whereas the oxides are less than 5 years old based on 228Th/228Ra. Most mound and chimney samples are dominated by barite and amorphous silica; sulfides occur in variable amounts that in decreasing order of abundance include sphalerite, galena, pyrite, and chalcopyrite. Anglesite, cerrusite, and a Pb phosphate occur as late-stage interstitial phases. Some mound samples have fragmental textures; layered clasts composed of chalcopyrite and pyrite may have been derived from collapsed chimneys. Despite the abundance of barite, samples contain high concentrations of Zn (to 23 Wt.%), Pb (to 13 wt.%), Ag (to 500 ppm), and Au (to 15 ppm). Copper is enriched in a few mounds samples, up to 3 wt.%, but is typically <1 wt.%. Other significant metal enrichments include Sb (to 1320 ppm), Cd (to 1180 ppm), and Hg (to 55 ppm).

Jan 1, 2011

By Timothy F. McConachy

Hydrothermal fluids emanating from the seafloor rise as buoyant plumes, entraining ambient bottom sea water on the way up, until they reach density equilibrium and spread laterally in a direction that is governed by near-bottom currents. Plumes provide targets for focussing exploration for seafloor polymetallic sulfide deposits associated with active hydrothermal vents because their lateral and vertical extent is commonly orders of magnitude larger than the vent field from which they originate. Black smokers can inject on the order of 10,000 µg of particles per liter into a sea water column that normally contains only about 10 µg of particles per liter. The resulting plume should be characterized by increased particulate concentration with respect to background sea water and, therefore, provide a measurable gradient towards the source of venting. By utilizing the ability of particles to scatter light, we employed a real¬time, acoustically telemetered, nephelometer to measure this gradient, and mapped the size, shape and particle concentration of plumes at an active spreading center on the Southern Explorer Ridge at lat 49°45.6&apos;N and long 130°16.2&apos;W. Isopach and particle concentration data indicate the presence of two separate but overlapping plumes. The first is associated with a known vent field called Magic Mountain; the second with a new field called AGOR 171, 1.2

Jan 1, 1986

By Steven D. Scott

Several polymetallic sulfide deposits (copper, zinc, f lead, silver, f gold) presently exposed at the surface of the ocean floor are of sufficient size and apparent grade that they will someday be seriously considered as mineable resources. Responsible ocean mining may have some real environmental advantages over land mining, although they both share the same downstream problems caused by smelting and refining. The area of disturbance for an ocean mine would be much less than for an equivalent sized deposit on land around which considerable rock has to be excavated in order to get at the ore. Acid mine drainage, a very serious problem in land ming, would not be a concern in the alkaline and oxygen deficient environment of the deep ocean. There would undoubtedly be loss of habitat for some marine organisms but this could be minimized by mining deposits that are no longer hydrothermally active and therefore support little life. The risk of severe corrosion and thermal damage to the mining equipment at hydrothermally active sites would probably preclude their recovery in any event. The scientific community and environmental advocates should take advantage of the long lead time before ocean mining commences to insure that the environmental mistakes of the past, as encountered in some land mining, are not repeated. In order to fully understand and thereby mitigate the consequences of recovering seafloor sulfides, test mining of a small deposit using the German-designed high capacity television grab, preceded and followed by detailed observations of the mining site from a submersible, is proposed.

Jan 1, 1992

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 Roger Amato

The 1982 United Nations Convention on the Low of the Sea includes provisions under Article 76 for extending a coastal State&apos;s jurisdiction beyond the 200-nautical-mile (nm) Exclusive Economic Zone (EEZ) and for establishing the seaward limits of sovereign rights over natural resources. Article 76 prescribes a set of methodologies for determining these outer limits based on physiography and sediment thickness. The methodologies were applied to each of the five continental* margin areas of the United States - Atlantic, Pacific, Gulf of Mexico, Alaska, and Pacific Islands-using existing digital hydrographic and geologic data. Figures 1 and 2 show the results of applying the methodologies to the Atlantic, Pacific, Alaskan, and Gulf of Mexico continental shelves. Figure 1 depicts the preliminary limits of each of the Article 76 determinations for the Atlantic and Gulf of Mexico continental shelves. The Atlantic limits were described by Carpenter, Thormahlen, and Amato (1995) at the 26th Underwater Mining Institute.1 The limits for the Alaskan continental shelves are shown in Figure 2. Additional areas beyond the 200 nm EEZ are highlighted. These include a small area north of the U.S. - Canada boundary, containing 7,000 km2, a large area north of Point barrow (395,000 km2), and a third area north of the Aleutian Islands (178,000 km2). The shelf between the first two areas appears to have sediments thick enough to qualify for the 1 percent method (Irish Formula); however, year-round ice cover has prevented acquisition of seismic or drill data. The entire northern Alaska shelf is prospective for petroleum The Gulf of Mexico (Figure 1) has two small areas beyond the EEZ known as "doughnut holes." One is south of Louisiana and includes part of the Sigsbee Escarpment, an area believed to have potential for oil and gas. Oil was found on Sigsbee Knoll in cores from Deep Sea Drilling Project&apos;s Leg 1 cruise in 1968. The Sigsbee areas contains about 6,000 km2. The second area is south of the Florida panhandle and contains about 12,000 km2.

Jan 1, 1996

By Gregory Abramov

Borehole Mining (BHM), a remotely-operated waterjet mining method (Figure 1), has recently achieved two major milestones. It was, for the first time, applied to the extraction of manganese ore and at temperatures below freezing. The 1St stage is a demonstration test that is now underway just north of Emily, Minnesota, where the manganese ore is located 100-160m below the surface and its reserves are estimated to be in excess of 500,000 tons. The deposit was discovered over 60 years ago but, due to the fragile and sensitive nature of this Land of 10,000 Lakes (nickname for the State of Minnesota) and strong environmental restrictions, the iron/manganese reserves were deemed unrecoverable and remained untouched until late 2010 when permission for a single-hole demo-test was issued by the local Department of Natural Resources.

Jan 1, 2011

By Peter A. Rona

The recent discovery of the first black smoker-type hydrothermal venting and massive sulfide mineral deposits at a site in the rift valley of the slow-spreading Mid-Atlantic Ridge near latitude 26°N, longitude 45°W (Rona et al., 1986, Nature, 321: 33-37), demonstrates that a complete series of hydrothermal mineral deposit types exists at slow-spreading oceanic ridges (half-rate = 2 cm/y), similar to the series previously known at faster-spreading oceanic ridges (half-rate > 2 cm/y). The largest hydrothermal mineral deposit known at a seafloor spreading center is a stratiform massive sulfide body with bulk dry weight of about 100 x 106 metric tons in the Atlantis II Deep at the slow-spreading axis of the Red Sea. This observation invalidates the concept that size of a hydrothermal deposit is directly proportional to rate of seafloor spreading. Instead, the occurrence, grade and size of a hydrothermal deposit formed at a seafloor spreading center is controlled by anomalous chemical and physical conditions which may occur at extremely localized sites at the full range of spreading rates. The basic hydrothermal process involving subseafloor hydrothermal convection driven by magmatic heat sources appears to be similar at slow- and faster-spreading centers. However, differences exist in the periodicity of magmatic cycles that energize hydrothermal circulation (104 y at slow-spreading centers; 103 y at faster-spreading centers); in the distribution of hydrothermal sites along a spreading axis (estimated 100 km along slow-spreading centers; 10 km along faster-spreading centers); and in residence time

Jan 1, 1986

By Stewart B. Nelson

With the pending U.S. ratification of the United Nations Convention on the Law of the Sea (UNCLOS), the subject was raised as to the Convention&apos;s potential impact on U.S. ocean science. The Ocean Studies Board (National Academy of Sciences) elected to convene a two-day workshop in October 1995 to consider the potential impacts and to determine whether or not they warranted a more formal and intensive study. A review of the workshop discussions and deliberations concerning the matter of UNCLOS and U.S. ocean science will be presented.

Jan 1, 1996

By M. E. Williamson

In September 2005 Williamson & Associates, Inc. delivered the BMS2 remotely operated seafloor coring system to the Japan Oil, Gas & Minerals National Corporation (JOGMEC). During acceptance trials aboard the JOGMEC research vessel R/V Hakurei Maru No. 2 the BMS2 successfully recovered 7.44 m of rock core in 3377 m water at a site near the crest of a seamount about 500 nm SE of Japan. Hydrogenous ferromanganese oxide crust, basaltic lava, sandstone and volcanic sediments were sampled with near 100% core recovery. The BMS uses rotary rod coring tools to collect samples to a maximum depth of 30 m in water depths up to 6000 m. Depending on bottom type to be sampled, the BMS tool magazine can be loaded with various drilling tools including core barrels with different bit types, drill rod and bore hole casing. The drill has 9 video cameras, a suite of sensors and 60 hydraulic functions powering thrusters, telescoping legs, seawater pumps and all of the standard drilling controls. The BMS provides deep water investigations with the functionality of conventional diamond bit rod drilling currently the mainstay of exploration programs in land mining.

Jan 1, 2005

By William D. Siapno

The International Marine Minerals Society has now come of age! Previously known as the International Marine Mining Society, it was an informal group without officers, by-laws or official status. Despite the lack of formal structure, the Society has cosponsored symposia both in Europe and in North America including the 16th Annual Underwater Mining Institute in Halifax, Nova Scotia, last year. The roster of members is now sufficient to emerge as a fledgling professional society. To this end an ad hoc committee was appointed to prepare by-laws stating the objectives of the Society, provide the procedures for the election of officers and other guidelines essential for the operation of the organization. This paper briefly summarizes the history of the group, the by-laws, together with membership requirements.

Jan 1, 1986

By T. Schoening

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

Sep 14, 2011

By Igor E. Mikhaltsev

This paper concerns the continuation of work on the deepwater non-oxygen cycle heat energy generating systems. The 25-kW prototype of a universal deepwater turbine-electric energy source with hydrazine-hydrate as the primary heat production chemical is described in short and its abilities are discussed. The ?hydrazine-hydrate 64? is a catalytically dissociated heat production chemical (H2H4 ? nH2O) with 36% of water. The system was designed for work in any depths of the ocean down to 6000 m. It was built and tested working in the testing chamber in the ambient hydrostatic pressure of 600 bar. Then it was tested in the autonomous programmed regime in the Atlantic Ocean. The privileges of that energy system for any bottom installations or moving devices designed for ocean mining which need high power energy sources (20-100 kW and more) are discussed. The important needed step forward is raising the efficiency of the system which needs some investigation work in known directions. It is supposed that the possibility of getting about 5 kg/kWh with improved battery charging possibilities could be achieved. This might make the system even more profitable for mining operations.

Jan 1, 2001

By Ivo Dreiseitl

Bottom sediment sampling by means of a box corer, as a direct method of deep seabed exploration for polymetallic nodules, is the most comprehensive way to obtain various types of geological information on points forming a network of stations. However, direct information is lacking from areas separating those stations and has to be approximated by interpolation or extrapolation, which leads to uncertainties. Sediment sampling with a gravity or piston corer can provide information on the superficial, up to 4 m thick, part of the sedimentary cover. As opposed to box coring, gravity or piston coring provides no information on nodule abundance. Information for unsampled areas can be gained by application of remote techniques of exploration. The techniques of choice in visualising nodule-rich fields, nodule-free areas, hard rock outcrops and other obstacles for seafloor mining involve using sonar and continuous deep sea (CDS) camera. Seafloor mapping can be rendered with two major sonar types: the side scan sonar used to obtain seafloor imagery and multibeam sonar for bathymetric data; the two types are usually combined and work with an intermediate frequency profiler. Photo-profiling by means of a deep sea towed camera provides a series of seafloor photographs, each supplemented with information on the area covered by each frame, including the nodule abundance. Remote techniques have been quite frequently applied by the Interoceanmetal Joint Organization (IOM) in nodule field exploration. Recently, geoacoustic techniques (side scan sonar + profiler) and CDS were applied for exploration of IOM?s first prime area H11 (5372 km2) on 6 transects. During the IOM-2009 cruise, a total of 295 km of geoacoustic transects and 344 km of photo-transects were surveyed. The data obtained were processed with the aid of earlier information produced by multibeam sonar surveys. The aim of this paper is to demonstrate the advantages of remote techniques, particularly with regard to application of the towfish device, for geological and geotechnical applications in exploration for polymetallic nodules.

Sep 14, 2011