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By Tap Pryor

A very small nation with large seabed resources requires a strategy. The simplest approach is to duplicate every step taken by the United Nations (UN), in its own leasing programme. In addition, the smaller nations must sell itself and its competitive offering. It is one thing just to await applicants and/ or tenders, another to work to make the leasing seem like a very good idea. This cap be achieved through publications, correspondence, meetings (such as the Underwater Mining Institute, but especially through pro-active planning, seeking the ideal technologies in both harvesting and processing. The ideal would be some combination that could begin quickly and on a small scale. It must be within the UN environmental guidelines. To meet the "quick and small criteria," simple harvesting and physical processing methods must be given the highest priority. Once these are satisfied, then marketing studies can be completed. There is, of course, a market for every element but only careful engineering and cost analysis will determine accessibility. What is required is a stepwise approach, gaining greater and greater credibility at each step. In fact, much planning can be done for very low cost. In the Cook Islands, the first crucial step was the East-West Center publication which pulled together all facts in one volume and which found the local resource to be richer in significant ways than Clarion-Clipperton. Most seem to believe that it could be many years before full production is possible, but this has been conventional wisdom for so long that it has taken on the suspicious aura of myth. Is it real? Have all possible recent technologies such as robotics and physical processing been taken into account? Either way, it is essential that a comprehensive approach be taken so that all factors from resource to market are considered as inter-related until a single business plan emerges. When that is in hand and when its profitability and risk levels are found to be credible, adequate investment funds are available.

Jan 1, 1994

By Akira Usui, Sayuri Kubo, Satoshi Tokeshi, Shingo Kato, Katsuhiko Suzuki, Teruhiko Kashiwabara

"INTRODUCTIONFerromanganese (Fe-Mn) crusts are a kind of marine chemical sediment composed of Fe and Mn oxy-hydroxides as well as small amounts of clastic sediments, which are ubiquitously found on the surface of slopes of seamounts and oceanic plateaus at depths from 900 to 5500 meters below sea level (mbsl). Fe-Mn crusts contain extremely high concentrations of useful minor metals such as Co, Ni, Te, REEs, and thus are expected as submarine mineral resources. Also, Fe-Mn crusts record the change of chemical compositions of seawater during last several tens million years, which allow us to obtain clues to clarify the paleoenvironmental conditions at the time of its deposition. However, occurrence, chemical compositions, microbial community and growth patterns of ferromanganese crusts are yet fully understood. Hence, a comprehensive study on the genesis of ferromanganese crusts, such as growth rates and enrichment processes of elements, is required to better understand their resource potential as well as their applications to paleoceanographic study.Based on the resource potential of ferro-manganese crust, the project entitled “Next- Generation Technology for Ocean Resources Exploration” was launched as one of the governmental projects to develop the exploration technology based on the scientific research on the submarine resources such as hydrothermal deposits (e.g., a poster by Kawada et al.), ferro-manganese crusts. We have made several research cruise to seamounts in the north-western Pacific such as Takuyo-Daigo and Takuyo-Daisan seamounts (Fig. 1) ."

Jan 1, 2017

By Thomas Pichler

In the past marine mining technology has focused on bulk mining of base metals from polymetallic massive sulfides. This has not been very successful because of the relatively low unit value of these metals and other reasons such as water depth, etc.. The process of gold enrichment in hydrothermal deposits is controlled through five different factors: (1) nature and source of the solution, (2) source of the gold, (3) a mechanism for mobilizing and transporting, (4) a mechanism for deposition, and (5) a mechanism to preserve the deposit. Gold has been identified in marine polymetallic massive sulfides from various locations on the ocean floor (e.g., spreading centers, seamounts) with contents ranging up to 5 ppm Au. This is within the current range of 1.0 to 7.0 ppm gold content which classifies gold ores. The gold appears to have been derived during hydrothermal alteration of the oceanic crust. Until the present there has been little attention to the possibility of mining gold or other precious metals in the marine environment. However, the magnitude of hydrothermal alteration (seawater can penetrates to a depth of 5 km into the oceanic crust) and primary gold contents of the rocks in the pathway of the fluid indicates that major gold deposits must have formed on or in the ocean floor, but they have not been found. To find a big deposit might only take an exploration model exclusively designed for gold exploration on the ocean floor.

Jan 1, 1993

By Ki-Hyune Kim

The Korea Ocean Research and Development Institute conducted its first exploration for deepsea mineral resources in 1983, and began a systematic deepsea prospecting in 1989 among Micronesian islands and in central and eastern parts of Carion-Clipperton fracture zones of eastern Pacific. With the arrival of R/V Onnuri in 1992, KORDI commenced a full-scale national program for nodule exploration. The total area surveyed by KORDI covers more than 1,500,000 km2. At the end of 1993, based on the collected data, Korea designated 300,000 km2 in the Clarion-Clipperton fracture zone as prospective mining area for manganese nodules, and accordingly, the government of Korea submitted the application in January of 1994 to the United Nations for registration as a pioneer investor and for the allocation of a pioneer area. This application was approved by the General Committee of the Preparatory Commission in August 1994. As a result, Korea became the 7m pioneer investor under the United Nations Convention on the Law of the Sea. KORDI is now carrying out detailed exploration survey and environmental studies in the registered area to fulfill required obligations to UN, and Korea will continue exploring the last frontier on earth. It is KORDI's unshaken calling to be successful in exploiting deepsea resources to provide our nation resources it lacks. It is not only a challenge to explore deepsea, but it is also our national mission to explore and succeed in our endeavor for future generation.

Jan 1, 2011

By Charles L. Morgan

In a commercial effort to characterize deep seabed manganese deposits in the Clarion-Clipperton region of the northeastern tropical Pacific, Ocean Mineral s Company carried out 16 expeditions to the region between -1978 and 1981. During these cruises OMCO collected substantial data. Activities included acoustic profiling, video and photographic imaging of the seabed, and sampling of the deposits with dredges, box cores and free-fall grab samplers. In 1990 the samples, photographs, technical reports and computer data bases which resulted from this work were archived at the Marine Minerals Technology Center at the University of Hawaii. This preliminary examination of the collection focuses on the biological observations made from almost 10,000 photographs of the seabed and the manganese nodule size distributions and compositional data from the free-fall grab recoveries. Regional trends are evident in all three data types. The biological examinations of the seabed photographs show significant geographical trends, with greater abundances of organisms being noted in the northeastern extreme of the region, decreasing toward the southwest (11.4 to 2.7 observations per 100 m2; 460 to 190 g per 100 m2). The nodule size distributions suggest that the ratio of the nodule burial rates to growth rates systematically decreases over the same range (0.65 to 0.36 nodules buried per 1 cm of growth). Preliminary geostatistical analysis of the ore grade data show that, in addition to high local variability, some deposit

Jan 1, 1991

By P. C. Hollick

Two marine diamond deposits on concession 2b off Namaqualand along the South African Coast, have been systematically mined over the past year by the mv Moonstar. The two deposits, Smith?s Ulcer and Wedge Point Basin, are comparable in morphology, straddled the same water depths and have similar geology yet have given very different recoveries when compared to their respective grade models. These differences are best ascribed to the different style of mineralisation observed within the two deposits which has been directly controlled by the bedrock morphology. The smith?s Ulcer deposit has been formed in a metagreywacke bedrock displaying a strong north-south trending foliation which dips steeply to the west. Consequently the mineralisation is confined to narrow north-south linear trends with limited lateral extent (less than 5m) making extraction extremely difficult and somewhat variable. RE factors (recovered grade versus estimated grade) for this deposit range from 0.5 to 1.1. The Wedge Point Basin deposit is formed in a micaceous metaquartzite with a conjugate southwest northwest joint set, the southwest lineation being the more prominent, and structural foliation dipping gently to the west. The resultant style of mineralisation is confined to basinal features defined by topographical lows and is fairly lateral in extent (in order of 50m). Extraction of the mineralisation from this deposit is less arduous with recoveries more uniform, RE factors are frequently in the range 2 - 3. This style of mineralisation is more in line with what is to be expected from marine alluvial deposits, the nugget effect of diamond concentration being responsible for the high RE factor. The long narrow linear trends observed in Smith?s Ulcer demonstrably require a specialised approach in successfully sampling, modeling and ultimately mining.

Jan 1, 1998

By Marco Figoni

The increased interest on deep water minerals resources is a challenge for both mining and oil industry. The exploration and production of oceans minerals require a synergy between of different technologies. While mining industry is leading the dredging and processing part of the system, oil industry is contributing through development of ore lifting technology based on existing subsea knowledge. The paper presents an overview, based on published projects around the world, of different approaches to marine mining. Several exploration techniques and offshore production systems were already designed and assessed, all of them with apparently positive results. Exploration phase is well advanced and in continuous expansion allowing the discovery of increasing resources around the world of different nature but production can be considered to be in an early stage. Different from onshore mining, subsea operations require a closer cooperation with international and local authorities to preserve as much as possible the environment. There are still many uncertainties at respect and all the exploration process must be carefully evaluated to allow subsea mining to develop in a sustainable manner. Technically, mining at seabed was already demonstrated and the process is based on three main components, namely seafloor mining tools, riser and lifting system and production vessel support. This layout is based on the concept that ore must be disaggregated at seafloor first, transported to surface in form of slurry that must be dewatered before loading to be transported to processing plants onshore. The challenges are rising because the environment and safety must be taken into consideration as a priority when evaluating the efficiency of the system. The most critical challenges regarding the production operations, especially in deep water are the deep-sea excavation process, the transport of large slurry volumes, the slurry abrasivity, the power supply management and the subsea

Sep 14, 2011

By Robert Goodden

It is well known that diamonds are found in Kimberlite pipes within the earth’s crust and are also discovered where erosion has released them to be concentrated by rivers in trap sites within alluvial gravels. Few people are aware however, that diamonds are now being found in significant quantities at sea. And that the rugged marine environment has ensured that the quality of diamonds in the sea is predominantly gem quality. Shortly after intrusion of Kimberlites into the host rocks of the karoo in the Cretaceous period massive erosion occurred when torrential rivers carried diamonds from their Kimberlitic source rocks down the rivers and into the sea. In the sea they have been subject to a transporting and concentrating dynamic, which has deposited them in trap sites along the West Coast of Africa for hundreds of kilometers. In the last 60 million years the sea level along the West Coast has varied in steps from the current sea level to – 300m. With time at each beach level the sea has reconcentrated the diamonds previously carried down. These old beach levels exist at roughly 10 meter intervals. Each previous sea level now provides a target for marine miners. Marine diamond mining was started 46 years ago by the first pioneer, a Texan, Sammy Collins. Collins brought the potential of marine diamonds to the attention of major mining companies. With now outmoded technology Collins had days when he recovered pockets of high grade gems worth several million dollars; an excitement hard to equal in any walk of life. Amongst marine miners there is still a strong pioneering spirit but the industry has matured and now aims to consistently produce over two million carats of gems a year. The potential resource is huge stretching up to 30 kilometers offshore along the West Coast of Africa from South Africa to Angola.

Sep 24, 2006

By Sven Petersen

In April 2010 three REMUS6000 series autonomous underwater vehicles (AUVs) have been used to simultaneously map large areas near the Mid-Atlantic Ridge (3°N) axis in water depths ranging from 1,000m to 4,000m. One vehicle was provided by the Leibniz-Institute for Marine Science, IFM-GEOMAR (Kiel, Germany) the other two were provided by the Waitt Institute for Discovery (La Jolla, USA) and managed by the Woods Hole Oceanographic Institute (USA). The REMUS6000 vehicles, manufactured by Hydroid Inc. (USA), are "cigar-shaped" vehicles (4m long and weighing approx. 900kg) and consist of a tapered forward section, a cylindrical midsection and a tapered tail section. An internal titanium strongback, which extends through much of the vehicle length, provides the structural integrity and acts as a mounting platform for syntactic foam, equipment housings, various sensors and release mechanisms. The AUVs can be used in various payload configurations such as multibeam bathymetry, electronic still camera, or subbottom profiler. For these missions the electronic still camera configurations was installed. An EDGETECH 2200M dual frequency (120/410 kHz) side scan sonar was used to map the seafloor, but other frequencies are readily available for more options in resolution and range. The 120 kHz side scan transmitter was used for most missions in order to map large areas (increased range) and to be able to fly at higher altitudes (between 70m and 90m) above the rough seabed encountered in this area. The maximum slant range was between 600m and 700m on both sides resulting in a swath width of up to 1.2 km. Line spacing ranged from nearly 1,000m in flat areas down to 400m in steep terrain. Side-scan mosaics were generated with a 1m resolution. Selected areas were targeted by the higher resolution 410 kHz transmitter as well as by bottom photographs flying as low as a few meters above the seabed. The vehicles navigated autonomously using a combination of inertial navigation (Kearfott T-24 or T-16 INS) and long baseline acoustic navigation by computing their range to two moored acoustic transponders. Working efficiently in this rough topography at speeds above 3 knots was only possible due to the obstacle avoidance capabilities of these AUVs.

Jan 1, 2011

By Ning Yang, Yuxiang Chen, Ming Chen

An ultraviolet laser Raman spectrometer was developed to detect and analyze material components of seawater, seafloor sediment and rock at a depth of 7000m maximally. Wave length of the excitation resource of the spectrometer is set to 355nm, which can enhance eigen scattered intensity and detecting sensitivity, and avoid fluorescence interference. Miniaturization design was adopted for deep-sea application. Design of the optical system and pressure cartridge, material selection and seal design of the observation window, and design of the Lithium batteries are the key technologies in the procedure of research and development. The spectrometer was carried by a Lander sank to sea bottom of the Pacific's Mariana Trench for verification. During the sea trials, data acquisition for Raman spectra was conducted for analyzing seawater in the detection area, and the spectrometer was verified synthetically. According to the data, the spectrometer is stable and practicable with high resolution and precision, and it is appropriate to detect and analyze composition of substance under the tremendous ocean.

Jan 1, 2017

By Jung-Keuk Kang

Recently, the Korean government prepared a strategy for deep seabed mining, which consists of three stages for 20 years until 2010. The first step of the program is focused to conduct deep seabed exploration until 1993. The apparent "hurry-and-spend to catch-up" policy that the Korean government has shown in deep seabed mineral exploration was motivated by an effort to qualify a prerequisite requirement to be a pioneer investor as a developing country under the terms of Resolution II and the New York Understanding. Since 1983, KORDI (Korea Ocean Research and Development Institute) under the auspices of the Korean government has carried out deep seabed mineral exploration. The KORDI had a joint exploration program with USGS from 1989 to 1991 aiming to evaluate the potentiality of manganese nodule in the western part of Clarion-Clipperton Zone as well as that of manganese crusts in the western Pacific. In 1992, Korean government accelerates its program by the confirmation of national policy and the equipment of new built research vessel, Onnuri-Ho. The RIV Onnuri-Ho is about 1400 G/T, which is equipped with various advanced instruments including GPS, multi-beam echosounder (Seabeam 2000), multi-channel seismic system, and MDM system.

Jan 1, 1992

By Richard Petters

Williamson and Associates, Inc of Seattle, Washington has recently built a remotely operated seafloor coring system for Nichiyu Giken Kogyo Ltd and the Metal Mining Agency of Japan (MMAJ). The system is designed to core to depths of 20 meters in 6,000 meters of water and will be operated from MMAJ's research vessel Hakurei-Maru No. 2 The corer uses rotary rod coring methods and will recover a core diameter of 44 mm. To facilitate coring through soft or unstable formations, the corer has the ability to set casing. The corer is fitted with thrusters for positioning during landing and telescoping legs for leveling. The system is operated through a 12 km electro-optical cable. Data displayed to the operator provides the operator with real-time feed back and control over the coring process. The operator has independent proportional control over bit weight, advance rate, rotary speed, and flushing water flow. The process of making up, breaking down and storing the drill string is automated and is controlled by a logic driven software routine. The system is currently undergoing trials in Japan. This presentation will discuss the drill's capabilities and should be of interest to those in need of a tool for assessing the thickness of marine mineral deposits.

Jan 1, 1996

By Dan Johnson

The discovery of rich alluvial diamond deposits on Namibia?s Skeleton Coast in 1908 began a period of intense exploration and mining off the coastal sand; and shallow surf zones. In the mid-60s a Texas entrepreneur, Sam Rollins took the search to the seafloor. The inhospitable conditions encountered made the early going difficult. After a slow start, the past 10 years have seen much progress in geologist?s understanding of the deposition mechanics and the use of sophisticated geo-physical and sampling techniques to aid in the discovery of economic deposits. Diamondfields, in a joint venture with BHP and Benguela Concessions, began an exploration program in 1994 for sea-bed diamonds off the Port of Luderitz in Namibia. This program has progressed to a mine development program with the potential of creating a 500,000 carat per year operation. The mining technologies being considered include state-of-the-art, remotely operated sea-bed crawlers and high volume dredges feeding to semi-mobile processing platforms. The company's objective is to use the best proven technology to create an environmentally responsible operation with the lowest fixed operating costs and the longest and safest weather operating window of any offshore operator working Africa's diamond coast.

Jan 1, 1998

By Harald Brekke

On 13 July 2000, the ISA adopted the Regulations on Prospecting and Exploration for Polymetallic Nodules in the Area. The first contracts for such exploration were issued by the ISA the same year. The duration of exploration contracts is 15 years, after which the contractors are expected to go into exploitation. In 2013, ISA with the LTC initiated the process for developing the regulations for exploitation, and are currently working on the first draft to put forward for the Council. In the meantime, the first seven exploration contracts have expired, and been given five years extensions in order for the contractors to get ready to apply for exploitation contracts. According to the current draft of the exploitation regulations, an application for an exploitation contract shall be accompanied by all data acquired during the exploration phase, a mining plan, a financing plan, and a set of environmental plans (i.e. an environmental impact statement, an emergency response and contingency plan, environmental management and monitoring plan, and a closure plan). All of these plans have to be based on substantial scientific and technical data and information. The mining plan requires geoscientific data regarding the mineralogy and grade of the nodules, and the physiography of the mining site as a basis for the consideration of critical aspects, inter alia for making reliable resource estimations, design the mining operations, and forecast revenues. The environmental plans require the input of a substantial set of bioscientific data and information on the exploitation technology in order to establish base-lines, and monitor and evaluate the effects of the mining operations. Under the exploration contracts, such scientific data have been acquired and reported on an annual basis to the ISA. Some testing of mining equipment and experiments on the extraction of metals have also been performed by some contractors. These scientific and technical data from the exploration phase will be the basis for the for the preparation of the studies, plans and documents required for the applications for exploitation. No time frame is specified for the preparations of an application but it must be assumed to take place before the expiration of the exploration contract.

Jan 1, 2018

By LeRon E. Bielak

Public Law 103-426 was signed into law in October 1994. Its provisions amended sections 8(k) and 20(a) of the Outer Continental Shelf Lands Act (OCSLA). The 8(k) amendment provides the Secretary of the U.S. Department of the Interior 001) with new discretionary authority to negotiate agreements for using Outer Continental Shelf (OCS) sand, gravel, and shell resources for certain projects of public benefit (e.g, beach, shoreline and coastal wetlands restoration that are under- taken by a Federal, State or local government agency). The new law also covers construction projects that are funded wholly or in part or authorized by the Federal Government. Under the law, the Secretary may assess a fee for use of the resource by taking into consideration the value of the resource and the public interest served. The law also requires that any Federal agency proposing to make use of OCS sand, gravel, or shell resources enter into a Memorandum of Agreement (MOA) with the DOI. An MOA would promote efficient coordination and resolution of inter- agency scheduling and issues. The law requires that Congress be notified before use is made of these OCS resources. The amendment to section 20(a) of the OCSLA clarifies that obligations concerning environmental studies extend to non- competitive lease situations and includes minerals other than oil and gas. The Minerals Management Service (MMS) is the DO1 agency responsible for interpreting and implementing the provisions of Public Law 103-426. The negotiated agreement approach is distinctly different from the competitive bidding requirements that have applied to all OCS minerals since the inception of the OCSLA. The MMS has opted to implement the new law in a nontraditional manner. Rather than issuinga body of new regulations to cover the negotiated agreement situation, or attempting to amend three sets of existing regulations, MMS is pursuing a less formal approach of providing guidelines. More weight is placed on the negotiation process itself and the legal agreement that consummates the process as the means for establishing ground rules, terms, and conditions under which qualifying projects may be conducted. This process must recognize and adhere to requirements of other laws, including the National Environmental Policy Act.

Jan 1, 1995

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 Maria Thornhill, Rolf Arne Kleiv

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

Jan 1, 2018

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

Jan 1, 2004

By Andrea Koschinsky, Luise Heinrich

(for an oral presentation) Activities for preparing future deep-sea mining offer the unique opportunity to study environmental conditions and anticipate adverse environmental impacts prior to the commercialization of the activity. Until know, environmental research has first and foremost focused on understanding direct impacts occurring at the seafloor or in the water column such as the removal of substrate, the suspension of sediment or the creation of particle plumes. Impacts occurring above the sea surface have thus far rarely been considered. The operation of deep-sea mining equipment, as well as of mining and transport vessels will be associated with a considerable energy demand. In the open ocean, this energy will be provided by heavy fuel oil (HFO), which is the cheapest and most common marine fuel. The combustion of HFO will be associated with the release of greenhouse gases and other pollutants. Deep-sea mining will thus directly add to already critical air pollution levels caused by international shipping. To contribute to a holistic assessment of deep-sea mining impacts and to address the previously outlined knowledge gap, we present the methodology to quantify the fuel consumption and associated emissions of a potential typical commercial manganese nodule mining operation in the Clarion-Clipperton Zone (Fig.1). Using the mine set up and energy demand estimates from a study commissioned by the German Federal Ministry of Economic Affairs and Energy supplemented by information from literature, we anticipate emissions of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), nitrous oxide (NO2), nitrogen oxides (NOx), sulfur oxides (SOx), particulate matter and non-methane volatile organic compounds.

Jan 1, 2018

Massive sulfides discovered in 1991 and further explored in 1993 in the eastern Manus back-arc basin, north of Papua New Guinea, represent one of the few modem seafloor occurrences known to he associated solely with highly siliceous volcanic rocks. As such they are very close analogs of ancient volcanogenic massive sulfide (VMS) ore deposits, and hence an excellent natural laboratory for developing new approaches for land-based VMS exploration. The Manus Basin lies between the active New Britain subduction zone and volcanic arc to its south and the opposed inactive Manus subduction trench to its north. It is being extended in a complex pattern of short neovolcanic zones and oblique transform faults. In its western sector, relatively mature back-arc spreading has created predominantly basaltic segments with characteristics and mineralization generally similar to those of mid- ocean ridges. At its far east, however, the basin is distinctly immature. The East Manus Volcanic Zone lies between two members of the Manus transform set, and is an en-echelon series of neovolcanic edifices constructed on extensionally thinned island arc crust formed during the earlier manus subduction episode. Individual edifices range from predominantly basaltic to predominantly dacitic in composition. Two of the edifices are known to be hydrothermally active, and a particulate plume with unknown source occurs in the seawater column above a third.

Jan 1, 1993