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By Andrew G. Hudson

The long-term economics of each of the four principal metals in marine manganese nodules (copper, nickel, cobalt and manganese) was evaluated to determine the anticipated viability of a nodule mining venture based on existing studies of the potential profitability of a nodule project. This included assessments of the lifetimes of land-based reserves, and examination and econometric modelling of the economic variables thought to affect nodule metal prices and demand. These analyses demonstrated that a) land-based reserves of the nodule metals were likely to last well into the future (100 400 years); b) average nodule metal paces were likely to stay a low levels for the foreseeable future; and c) the expected revenue stream from a twenty- ear nodule mining venture was substantially (42%) below that required to attract the necessary investment capital for such a high risk venture.

Jan 1, 1996

By Toru Yamasaki

"Bimodal lithostratigrafic assemblages are of significance in volcanogenic massive sulfide (VMS)-hosted lithology. The largest deposits are either bimodal-siliciclastic or maficsiliciclastic, and the presence of a significant siliciclastic component in the host stratigraphic succession favors large VMS deposits (e.g., Franklin et al., 2005; Barrie and Hannington, 1999). In the case of modern sub-seafloor VMS deposits in arc-related settings, the majority of deposits have been discovered in association with calderas or cauldrons (Halbach et al., 1993; Ishibashi and Urabe, 1995; Iizasa et al., 1999). These features are formed by the explosive eruption of silicic volcanoes, so that silicic host rocks and/or pumiceous volcanic clasts are generally observed around the ore deposits (e.g., Binns and Scott, 1993; Fiske et al., 2001). Caldera-like and graben-like morphological features therefore attract attention in geophysical surveys. However, silicic lithologies (dacite and rhyolite) normally contain only small amount of metallic elements (e.g., a few ppm to a few dozen ppm of Cu), whereas mafic rocks, such as basalts and basaltic andesites, contain significant amounts of metals (e.g., a few hundred ppm of Cu). Thus, the origin of metallic elements in VMS deposits associate with the silicic host rock remains unclear.The Iheya North Knoll is a volcanic complex in the middle of the Okinawa Trough. It is located in a young and actively spreading back-arc basin that extends for 1200 km behind the Ryukyu arc-trench system (Lee et al., 1980; Letouzey and Kimura, 1986). Several active hydrothermal fields have been recognized in the Iheya North Knoll. Mineralization at the Iheya North Knoll is characterized by relatively juvenile features consisting of VMS deposits with associated hydrothermal alterations to various degrees. Massive sphaleriterich sulfides at this site, recovered for the first time from beneath an active seafloor hydrothermal system, strongly resemble the black ore of the Kuroko deposits of the Miocene age in Japan (Takai et al., 2011). From February 11 to March 17, 2016, the SIP CK16-01 (Exp. 908) D/V Chikyu cruise was conducted at Iheya North Knoll and the rifting center of the Iheya Minor Ridge area, middle Okinawa Trough. The Iheya Minor Ridge area is also an active hydrothermal field, located ~30 km southeast of the Iheya North Knoll. In this area, basaltic rocks are widely distributed, and drilling has confirmed that the basaltic materials continue to ~120 m below the seafloor (Kumagai et al., in prep)."

Jan 1, 2017

By Nobuyuki Okamoto

The present three-year long phase of the SOPAC/Japan Deep Sea Co-operative Mineral Resources Programme [Programme], commenced in 2000. The Programme has been funded by the Government of Japan through the Japan International Co-operation Agency (JICA) and the Metal Mining Agency of Japan (MMAJ), since 1985. Field survey activities and associated data analysis and interpretation, for the Programme, has largely been carried out by the Deep Ocean Resources Development Co., Ltd. (DORD). The Government of Japan has, since 1982, recognised DORD as one of its ? Pioneer Investigators? for manganese nodules in the Clarion Clipperton Fracture Zone . Although the objective of this paper is to present the results of the drilling cruise that was conducted from December 2001 to January 2002, within the North Fiji Basin, in Fiji?s EEZ, it will also seek to provide a broad overview of the results of the cruise conducted within the Cook Islands in May to June 2000, as well as present preliminary results of the cruise conducted in the Marshall Islands in June to July 2002.

Jan 1, 2002

By D. Cronan

Both the S.W. Pacific and Caribbean island arcs are host to submarine hydrothermal mineral deposits, the former more so than the latter. In the S.W. Pacific, the whole gamut of such deposits occurs on the sea floor, sulphides, silicates, Fe and Mn oxides, whereas during the limited studies to date in the Caribbean only hydrothermal Mn oxides have been found to occur on the sea floor there in any abundance. Comparisons between the respective Mn oxides are thus the most fruitful at the present limited stage of our knowledge of Caribbean submarine hydrothermalism. Southwest Pacific hydrothermal ferromanganese oxides and their possible relationships to underlying sulphide mineralisation or bedrock anomalies (the geochemical window concept) has been a fruitful field of research in recent years. Certain element enrichments in crusts may be indicative of underlying mineralisation (Rogers et al. 2001). However, more recent studies on buried hydrothermal crusts in the S.W. Pacific (Cronan et al. 2002) have shown there to have been postdepositional diagenetic uptake of elements in them, and thus these elements cannot be used with any confidence in geochemical exploration for buried sulphide deposits unless sediment involvement can be eliminated.

Jan 1, 2002

By Du Gon Lee

This study presents a model to predict fate of resuspended sediment in the development of deep-sea mineral resources including manganese nodules under Clarion-Clipperton area of the Pacific Ocean. The manganese nodules are expected to be developed near future and major research is undergoing in Korea recently concerning many aspects of the mineral resources development. One aspect is about environmental concern related to the deep-sea development, and a major environmental problem is the resuspended deep-sea sediment. In order to quantitatively analyze the resuspended sediment in the water column during the deep-sea development, particle size distribution (PSD) was considered an important factor in this research. The model developed here includes PSD and coagulation process, as well as sedimentation process. The model is one dimensional in the vertical profile, and was designed to describe the change of particle size distribution in the water column in the given vertical point. Based on the mathematical modeling, a numerical model was developed. Using the model, basic simulation was performed under representative environmental setting of the deep-sea environment. The simulation showed the dynamics of change of particle size distribution for 50 m depth of water column from the deep-sea bed, up to 10 days of simulation time. The simulation results indicate that coagulation seemed an important factor in the fate of resuspended deep-sea sediment. As a result, this research shows that the particle size distribution approach, as well as considering the coagulation process, is needed and may be effectively applied to environmental impact analysis of deep-sea resuspended sediment. Key Word: Deep-sea Mineral Resources, Resuspended Sediment, Environmental Impact, Particle Size Distribution, Coagulation, Modeling and Simulation

Jan 1, 2003

By U. Schwarz-Schampera, P. Stoffers

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

Aug 24, 2006

By 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 Chul H. Jo

The functions of miner mainly include the pick-up manganese nodules laying on the surface of the seafloor, the separation them from sediments, the crushing the nodules and the covey to the inlet of the flexible hose. The miner is connected with umbilical cable that can supply power, instrument signal, communication data, etc. The major concerns of the system is to monitor and control the launching and retrieval operation, the landing, maneuvering and track keeping, to monitor the pick-up operation and to monitor the hydraulic system. Also as per the seafloor profile the track and pick-up processes need to be controlled. The recent research and development of deep sea miner is mainly focused on the efficient performance and workability in deep water. To communicate and control the miner, navigation and positioning system have been applied. As the miner is being deployed or retrieved, it is very critical to avoid any damage to the device that would be caused by the dynamic behavior of surface vessel or the minor itself with wave and current motion. The fast deployment and retrieve should be considered very important to minimize the possible damage. The paper introduces the various type of deployment devices and recommend the possible system to the miner developed by KRISO.

Jan 1, 2003

By Carolita U. Kallaur

In contrast with the United Kingdom, the Netherlands, and Japan, the marine mining industry in the United States exists at a very rudimentary level. Depletion of onshore resources has undoubtedly been an important factor in the development of marine mining industries abroad. However, the institutional framework presented by government can advance or present obstacles to the development of a marine minerals industry. The role of government involves questions of the degree of risk sharing between government and industry, as well as questions of the strategic and economic importance of developing the technology and the infrastructure to recover minerals. In 1984, the Minerals Management Service (MMS) created a program office to handle these questions and to respond to a potential increase in commercial opportunities that might result from the Presidential Proclamation establishing a U.S. Exclusive Economic Zone. A critical component to the success of the program has been the formation of partnerships with coastal States to pursue projects in areas of mutual interest. Such projects involve commodities showing commercial promise and strong public need. Such a cooperative approach lessens the risk of Federal, State, or private interests working at cross purposes.

Jan 1, 1992

By S. W. McCandless

Since the mid 1970's, the science of remote sensing has invented and demonstrated sensors that hold unique promise for users that operate in the marine environment. Earlier, visible and infrared sensors provided images and temperature maps of surface conditions, but the 1970's introduced active (radars) and passive (radiometers) microwave sensors capable of penetrating clouds and operating day or night over the world's oceans. Space-based observation satellites permit these systems to span the globe many times each day, providing a view of the world's oceans and Arctic areas consistent with daily and, sometimes, hourly changes in the marine environment. Experimental satellites launched by NASA proved that such systems had great scientific merit, but, even more importantly, they could produce information valuable to marine transportation, fishing, and resource exploration and extraction. This latter subject includes the off-shore search and production of petroleum and natural gas resources and ocean mining as well. A few early satellites, such as GEOS-3, Nimbus-7, and most notably Seasat established that global wind fields, all weather sea surface temperature, ocean topography and sea state, and fine scale images of wave patterns, surfactants,

Jan 1, 1986

By Luc Rombouts

The resources and reserves calculation of marine diamond deposits should be based on a systematic sampling grid. The distribution of the sample grade results tends to be very skew and has a large variance. A bias is easily introduced due to the fact that the grade distribution of the samples is very different from the grades of the area of influence. The temptation is always there to extrapolate the highest grade samples simply to their area of influence. If this is done, the higher grade areas will be systematically overestimated, while the lower grade areas will be underestimated. Such a bias should surely be avoided by weighing the sample grades in such a way with their neighbours, so that the estimated grades have a similar distribution as the grades of the blocks. The grade distribution of small mining blocks tend to be lognormal-like. If the coefficient of variation is known, i.e. the standard deviation divided by the mean, then the grade distribution of the small mining blocks is relatively well-defined. The distribution of the diamonds within the deposits can be simulated, based on the histogram of the sample results and on the semivariogram. The diamonds tend to cluster in trapsites. From the semivariogram and the histogram, the average size and spacing between trapsites, and the grade distribution within the trapsites, can be calculated using the model of the General Family of Discrete Distributions. Using such a simulated deposit, the grade distribution for different block sizes can be obtained. The grade distributions become more lognormal-like with increasing block sizes, as the trapsite effect is reduced.

Jan 1, 1998

Clark volcano is a large volcanic center on the active arc front of the intraoceanic Kermadec arc. It is one of the two southern-most Kermadec arc volcanoes (the other being Whakatane volcano) that sits on oceanic crust before the transition to continental New Zealand, and is underlain by the 17-km-thick Hikurangi Plateau, which is presently subducting beneath the southern section of the Kermadec arc. Unusual K-rich basaltic lavas have been recovered from Clark (1.5 to 2.25 wt.% K2O), together with more typical basaltic-andesite, andesite and dacite rocks. The total volume of the Clark volcanic center is ~90 km3, calculated from the summit of the volcano down to the 2,500 m contour (which marks the inflection point of the volcano flanks with the surrounding seafloor) and comprises two separate edifices similar in size; the northern one having a volume of ~4.57 km3 and the southern one 4.43 km3. The volcano has a maximum relief of ~1,645 m from the 2,500 m contour to the summit of the shallower northern edifice shoaling to 855 m below sea level. The northern edifice is comprised of twin peaks each consisting of a constructional cone, with evidence of sector collapse having occurred between the cones. A more recent, smaller cone again has grown on the eastern flank between these summit cones. Massive, blocky lavas and coarse talus dominate the summits of the cones, with finer-grained volcaniclastic material and sediments a feature of the volcano flanks. The southern edifice is noticeably more dissected than the northern one, having a pronounced horst in the centre of the volcano bounded by 5-6 km-long faults. There is no obvious constructional cone atop the southern volcanic edifice.

Jan 1, 2011

By Hjalmar Thiel

Since industry is progressing into the deep sea, marine scientists have expressed their concern about environmental disturbances which will be introduced by using the deep seafloor for mining metalliferous resources or as a repository for wastes. Environmental studies have been conducted on national levels and in bilateral or multilateral cooperation in the development of manganese nodule mining, as this is generally achieved in marine research. These investigations were partly large-scale and experimental approaches aiming at the assessment of the impacts expected to occur in commercial mining. The results elaborated till today and expected to be acquired in the foreseeable future may remain limited. Reliable impact evaluation will result from monitoring a Pilot Mining Operation (PMO). The lecture will present the broad outlines of a possible program and a preliminary calculation of approximate costs for such a combined industrial test and environmental monitoring event. Although the extent of necessary efforts for the environmental risks evaluation can only be estimated rather vaguely, it will become evident that the required human, technical, logistical, and financial resources to be mobilized will exceed industrial capacities and go beyond national funds. Therefore, such assessment of environmental risks is calling for broad international cooperation. While industrial developments for mining the deep sea will be ruled by competition or probably by restricted joint ventures, environmental care ranges outside competition and falls within the interest of all parties involved. Environmental studies, unlike technologies for the same function, do not primarily need duplication. International cooperation in PMO monitoring would equally well support all mining companies or consortia, it would minimize the efforts for all engaged in this challenging venture of deep-sea mining and it would maximize the precautionary discussion on and the care for the deep-sea environment.

Jan 1, 1994

By J. V. R. Prasada Rao

India is dependent for 60% of its annual requirement of copper and the entire quantity of nickel and cobalt on imports from outside the country. Land-based resources are either too meager or of too low a concentration for economic exploitation. This has prompted the country to look to deep seabed re- sources for meeting its rising demand for these metals. The Ocean Policy of the Government of India announced in 1982 talks about the need to map and assess the availability of minerals in the deep sea and to develop necessary technologies for exploration and exploitation of seabed minerals. To be self-reliant such technologies would have to be largely developed, tested and operated indigenously. The adoption of the Law of the Sea Convention in 1982 gave a fillip to India's desire to get into the field of deep seabed mining. India applied for recognition as a Pioneer Investor in Ocean Mining in 1983 and received allotment of a mine site of 150,000 km2 in the Central Indian Ocean in August 1987. Simultaneously, the Government has taken up a programme of development of technologies for exploration of the mine site for resource assessment, environmental monitoring also to meet the commitments like relinquishment of 50% of the area to the Preparatory Commission. Technologies for exploitation of these seabed resource like the mining system, transportation and extractive metallurgy have also been taken up for development in various research institutes largely in the government sector. While India's objective in the long term is to meet the shortage of copper, nickel, cobalt and manganese by the turn of the century, in the short term, the programme aims at application of the seabed mining technologies to meet the immediate needs of the country such as: a. Exploration for oil and natural gas. b. Exploration and exploitation of placer minerals and other deposits at shallow depth in India's EEZ.

Jan 1, 1994

By Dorothy B. Niell, O&apos

In its first three years of operations, the in-house programs of the continental Shelf Division of the Marine Minerals Technology Center (MMTC/CSD) have focused on the development of drill systems - technology and the improvement of techniques and applications of reconnaissance methods to marine mineral deposit characterization. Many of the technological advances made to date have been in direct response to specific requests from industry for drill systems needs, and from federal and state agencies seeking technical support for various research efforts. These cooperative programs have proven to be an extremely efficient and effective way for the MMTC to achieve some of the main program goals that were established for the organization at the outset: primarily, to encourage and assist U.S. industry in marine minerals research activities and to encourage cooperative work among research institutions, government agencies, and industry. The primary achievements of the MMTC/CSD to date include the development of the Remote Placer Drill System for rapid reconnaissance drilling of precious metal placer deposits (including both pneumatic prototype and hydraulic production

Jan 1, 1991

By Sukumar Bandopadhyay

The Marine Mining Technology Center (MMTC) was authorized by an act of the United States Congress in 1996. The act established several marine minerals research centers in the U.S., including one at the University of Alaska Fairbanks. The Alaska MMTC is funded through the Minerals Management Service of the Department of the Interior and concentrates its research in the Artic seas region. Recent research projects at the MMTC include, among others, a geographic information system (GIS) application to the gold placer deposits offshore Nome, Alaska, a marine gold placer reserve definition model using a neural network, and development of an expert system model for submarine tailings disposal (STD) planning and decision-making. Although geostatistics remains the most prevalent method used today for ore grade estimation, researchers have made numerous improvements over the years for accurately predicting grades of ore using various other estimation techniques. As a result, the neural network has recently emerged as an alternative to geostatistics for grade estimation purposes. A neural network is a non-linear, model-free estimator that is well-suited for noisy and/or sparse data environments. Neural networks perform best with non-linear spatial data, contrary to the stationary assumption of ordinary Kriging techniques. In the marine placer ore reserve definition model, the neural network technique was used to estimate placer gold reserves offshore Nome. This study demonstrated the utility of neural network modeling over other traditional ore reserve estimation methods, especially for high cut-off grades. Some of the relevant issues of neural network modeling were also addressed in the study. In testing, the neural network produced results that were close to those from geostatistical techniques including Kriging, polygon, and inverse distance methods.

Jan 1, 2004

By John W. Padan

The 1982 United Nations Convention on the Law of the Sea contains major provisions that U.S. negotiators have sought for over two decades. The internationally recognized right to the mineral resources of a broad continental margin is of potentially enormous future importance to the United States. Although water depths reach 10,000 feet in some of the deeper areas of the margin, technology is rapidly making those depths economically accessible. In 1997, production in the Gulf of Mexico will reach a world record water depth of 5400 feet. Of perhaps even greater importance to the oil and gas industry is the broadly acknowledged right for tanker transport of oil to take place throughout all parts of the world's oceans.

Jan 1, 1996

By Brenda J. Burd

A very extensive spatial and temporal database on benthic infauna and associated sediment metals has been collected for Island Copper Mine on Vancouver Island, B.C. Canada from 1969 (pre-discharge) to 1998 (3 years post-discharge). The tailings deposited as organically impoverished, copper-rich, clays, silts and sands distributed according to particle size, bottom turbidity currents and strong, vertically mixed tidal currents. In addition, a large deposition of coarser waste rock along the north shore of Rupert Inlet contributed substantial material in the shallower, near-field area.

Jan 1, 2001

By Tetsuo Yamazaki

Natural methane hydrate has been scientifically studied as a global carbon reservoir. However, in Japan, it?s potential as an energy resource has been industrially highlighted, because there are few domestic oil and natural gas resources in Japan, but many potential deposition areas for methane hydrate in the sea around Japan. Less CO2 discharge from methane compared with coal, oil and conventional natural gas for the same calorie value is considered an advantage for its use as an energy resource. Because methane hydrate is distributed at shallow depth in sediments on the ocean floor, accidental leakage of methane may occur while we utilize methane hydrate. Methane itself has a considerable impact on the greenhouse effect, if it reaches the atmosphere. Therefore, it is necessary to estimate its behavior in the environment after leakage if we want to use methane hydrate as energy resource. The mass balance after leakage of methane on the seafloor and in the water column can be studied through the analyses of natural cold seepages and hydrothermal activity.

Jan 1, 2004

By Michael J. Cruickshank

The University of Hawaii, Ocean Basins Division (OBD) shares, equally with the University of Mississippi, Continental Shelf Division (CSD), congressional funding for the Marine Minerals Technology Center, a Generic Minerals Center under the U.S. Department of the Interior's Mineral Institutes Program. The State of Hawaii supports the program by the provision of salaries for the Executive and Technical Directors and by the provision of fiscal, administrative, and facilities support through the Hawaii Natural Energy Institute, the Research Corporation of the University of Hawaii, and the School of Ocean and Earth Science and Technology. The Center's program of research, technology development and education is multi-disciplinary and international in scope. Activities since the MMTC/OBD was established in June 1988 have included: Research projects * Development of a Free-Fall Seafloor Hard Substrate Corer. * The Microtopography of Manganese Crust deposits. * Evaluation of the Cobalt Crust Continuum on Seamounts in the Hawaiian Exclusive Economic Zone. * Graphite Furnace Atomic Absorption Spectrometer. * Computer Aided Design Methodology for Power, Communication and Strength Umbilicals. * Characterization and Environmental Impact Assessment of Tropical * Reef-derived sands for Beach Replenishment.

Jan 1, 1991