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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 Jan Magne Markussen

The aim of the paper is to analyze the viability of commercial exploitation of polymetallic nodules, the time aspect for exploitation and the probable organization of commercial projects. METHOD My methodological point of departure is to view the various factors in context, and to differentiate between the various groups of actors. This involves taking as my starting point the interaction that exists between economics, technology, politics, law, the environment, and even psychology and ideology, and acknowledge that the various actors may well have differing motives for their engagement.

Jan 1, 1992

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 Eric J. Foell

Recognizing that the planned commercial exploitation of polymetallic nodules in the deep sea should be accompanied by environmental studies in order to protect this largest and least understood ecosystem of our planet, the German Ministry for Research and Technology has since 1989 funded a longterm and large-scale disturbance-recolonization (DISCOL) experiment in the abyssal Peru Basin of the equatorial South Pacific Ocean. The circular study site is located at 4150m depths and encompasses about 10km2 of relatively flat, heavily sedimented sea floor with low (< 15%) nodule coverage near an existing German nodule mining exploration license area. The RV SONNE, a large and well-equipped multi-purpose research vessel, served as platform for all environmental cruises conducted to date. The initial DISCOL expedition (SO-61, Feb.-March 1989) was carried out in two legs. During DISCOL 1/1, a study site was selected, a pre-disturbance baseline assessment was undertaken, and sea floor disruption was begun using the "plow-harrow", a uniquely designed disturber device towed repeatedly across the circular study area. During DISCOL 1/2, disturber deployments continued until the device had created 78 criss-crossing and partially overlapping tracks along which nodules were essentially plowed under while sediment from up to 15cm below the seabed had been turned over and exposed at the surface. In addition to the obvious within disturber track impacts, sediment mobilized by plowing drifted off with the prevailing near-bottom current and redeposited downstream, blanketing nearby areas not directly disturbed. Immediately after the disturbance phase, an initial post-impact sampling series was performed. The DISCOL Experimental Area (DEA) was revisited about six months (DISCOL 2, SO-64, Sept. 1989), three years (DISCOL 3, SO-77, Feb. 1992), and seven years (ATESEPP SO-106, Jan.-March 1996) after disturbance to collect further post-impact samples, monitor changes in the benthic community and follow the recolonization process. In addition to benthic community studies, plankton investigations were initiated during the third DISCOL cruise (SO-77) and continued during three further cruises (SO-78, SO-79 and SO-80/2) in 1992.

Jan 1, 1996

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 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 S. Rajendran

Gas Hydrates (Methane Hydrates) are solid, ice ? like substances composed of water and natural gas. They occur naturally in areas of the world where methane and water can combine at appropriate conditions of temperature and pressure and are found in the ocean bottom sediments and in some permafrost areas. Besides temperature and pressure, factors like bathymetry, sediment thickness, sedimentation rates, and total organic carbon content (TOC) also control gas hydrate formation in the sea. The stability of gas hydrates depends on the critical high pressure ? low temperature combination (0 - 17 bars, 0 - 25°C), which in turn dependent on the mix of gases from which the mineral is formed. As the critical parameters can be altered by deposition, erosion or slumping of sediments, formation or melting of ice cover, rise and fall of sea level and sudden temperature changes induced by tectonic activities, current flows or volcanisms, the gas hydrates tend to be very unstable. The Indian offshore is promising with the occurrence of gas hydrates in a total of about 80,000 km2 area in the bathymetry range of 700 to 3000 m as reported in the earlier surveys. A gas hydrate stability zone thickness map was prepared using bathymetry and sea bottom temperatures along the continental margins of India. This map is expected to provide the depth window while searching for the ?Bottom Simulating Reflectors? (BSR). The study indicates that a minimum water depth of 750 m is required for the formation of gas hydrates, and above which the chances for gas hydrates occurrences appear minimal despite other favourable conditions like presence of sediment rich organic content etc. Single channel seismic analog records (Gupta et al., 1998) suggests that Western Continental Margin of India (WCMI) offers greater promise with to gas hydrate occurrences, particularly with regard to the number of BSRs traced on the analog records as compared to the earlier surveys.

Jan 1, 2002

By Valery M. Yubko

"The conceptual basis of the developed model is based on the ideas that evolution of geological-geomorphological structure of the CCZ is controlled by four types of geologic factors: geodynamic, sedimentary, volcano-tectonic and erosion-lithodynamic. In terms of time span two factors (geodynamic and sedimentary) can be considered as permanent and the other two as sporadic.The geodynamic factor is responsible for two interrelated geological processes. One is going under conditions of the axial zones of spreading centers and results in formation of the CCZ basement. Historically this process is considered as a starting point for each of the heterochronous fragments of the CCZ. The second one controls gradual shifting towards the Pacific Plate (Hawaiian direction) and subsidence to greater depths of the neogenic fragments (basement). Thus, those processes control basic topography, geomorphology and the seabed depth within the CCZ.Volcanogenic-hydrothermal activity of the EPR is one of the main sources of the ore components, which finally compose manganese nodules as a result of complicated processes of their dissemination and transportation to the bottom in dissolved and organically bound forms.The role of the other constant factor (sedimentary) is displayed in two ways. Firstly, initial relief is smoothed under the influence of this factor, which, subsequently, makes favorable conditions for manganese nodules formation. Secondly, it favors transportation of the majority of the ore components, participating in manganese nodules formation into zones of active nodules formation."

Jan 1, 2017

By Seung-Kyu Son

Environmental properties of the northeast Equatorial Pacific along 131.5 degrees west, between 5 degrees and 13 degrees north latitude, were investigated in association with changes in water column structures during the summer seasons of 1998 and 1999. Climatic disturbances such as El Nino and La Nina, should have affected this area during the study period. In 1998, a thermocline where temperatures rapidly decrease with depth, was formed at 90~110 m water depth. However, in 1999, a very fluctuating thermocline was observed with latitudes. As a result of changes in the water column structures, biological and chemical environment also showed fluctuation parallel to the changes in other physical parameters. Inorganic nutrient depleting areas, especially for nitrate+nitrite and phosphate, or oligotrophic regions were extended down to approximately 100 m depth, which coincided with the surface mixed layer depth. In the euphotic zone, depth integrated nitrogen (N) and phosphorus (P) values were 34 g-N/m2 (grams of Nitrogen per square meter of sea floor), 7 g-P/m2 in 1998 and 130 g-N/m2, 18 g-P/m2 in 1999, respectively. The results indicated that nitrogen (96 g-N/m2) and phosphorus (11 g-P/m2) are supported by up-welling and down-welling phenomena with convergence and divergence in the study area. Biological parameters in the water columns were largely determined by the physico-chemical environmental parameters. Subsurface chlorophyll maximum layers were coincided with the formation of seasonal thermocline. Copepods were the dominant group of zooplankton community at three sampling stations (N5, N6, N10) terms of abundance, which was the same results of previous surveys for the past 3 years. Among copepod populations, Oncaea sp., Oithona sp. Clausocalanus sp., Acarocalanus sp. and juvenile copepodites were dominant Appendicularians, foraminiferans and radiolarians were also dominant. To investigate diel vertical migration pattern of zooplankton, repeated samplings from the water depth of 0~50m and 50~200m were conducted at KODOS (Korea Deep Ocean Study) area before and after sunrise. Zooplankton abundance was slightly higher after sunrise than before sunrise in the surface layer. Chlorophyll-a concentrations were relatively low as the concentration of sediment increased in most experiments possibly due to a decrease of grazing pressure of microzooplantkon such as ciliates, which is the efficient grazer on small-sized phytoplankton. Because copepod predation on microzooplankton may be prevented by the high concentration of sediment, resulting in lower grazing pressure on small-sized phytoplankton. The results obtained during the baseline study as a part of KODOS project since 1998.

Jan 1, 2001

By J. Robert Woolsey

A unique concept for a self-cleaning filter system has been designed and constructed which utilizes acoustic energy, coupled hydraulically with a subject liquid media, and a fine mesh screen to perform the following: 1. separation of solid suspended particles from a host liquid through the breakdown of surface tension; 2. enhanced filtration of liquid fraction from the solids fraction to specified limits, retaining a specified size range of solids, and; 3. continuous cleaning of screen, preventing screen blinding and promoting a continuous filtration process. The concept is the product of a cooperative program between the Marine Minerals Technology Center, Continental Shelf Division, and the Moscow State Mining University. The physical principals involved in the separation, filtration, and screen cleaning processes primarily relate to the characteristics and properties of the applied acoustic energy and the influence of this energy on the solids/liquid mixture. The acoustic energy introduced to, and acting on and throughout, the whole volume of the solids/liquid mixture, within the vessel body at any given time induces hydraulic pressure waves, which may be further described in simplest form as positive and negative semiperiods (which may or may not be equal in amplitude or period) of the basic wave forms. The processes involved may be considered in two phases. The first phase relates to the process of separation in which the acoustically induced force of acceleration manifests as vibro-agitation (thresh- old of cavitation) and possibly cavitation is the primary factor in the breakdown of surface tension between the solid particles and suspending liquid; i.e. water. In the case of compressible organic solids, the separation of liquid by squeezing may also be a factor.

Jan 1, 1994

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 Amy Gartman

The interactions between hydrothermal fluids and seawater result in minerals that range in size from nano- to macro-scale and constrain mineral emplacement, whether in hydrothermal chimneys or metalliferous sediments. Although broad similarities exist, and sulfides are the most important component of seafloor massive sulfide deposits, the specific mineralogy, size and therefore reactivity of particles emitted varies between hydrothermal sites in the global ocean, and even at different sites within the same vent field. The oxidation of sulfide minerals results in one of the major impacts of terrestrial mining of volcanogenic massive sulfides as it creates acid mine drainage. At marine hydrothermal vents, the chimneys themselves, as well as the ‘black smoke’ begin to oxidize as soon as they are in contact with ocean water; the breaking of sulfide minerals during marine mining will expose further surface area to seawater and oxidation. Although the cold temperatures and circum- neutral pH result in oxidation proceeding less rapidly than in many terrestrial systems, there is limited data on the kinetics of sulfide oxidation in seawater. Here, the oxidation of sulfide minerals in seawater and the implications for marine mining will be discussed, with an emphasis on nano-ZnS and sphalerite, including reaction kinetics, processes, and oxidation products.

Jan 1, 2018

By Kokichi Iizasa

Two major Kuroko-type deposits and minor sulfide deposits have been found in the middle Izu-Ogasawara (Bonin) Arc, Japan (Fig. 1). The Hakurei deposit, one of the major Kuroko-type deposits, was recently found in Bayonnaise knoll caldera in the nascent rift zone, which lies 20 km westward of the Sunrise deposit in Myojin knoll caldera on the Izu-Ogasawara volcanic front. The Hakurei deposit is a huge hydrothermal field measuring 500 m by 700 m in plan view. The Bayonnaise knoll caldera is mainly composed of dacite lavas and fragmental material on the caldera wall and rim, and its floor contains sediment composed of pumice, volcanic fragments, and hydrothermal clay. It is associated with a post-caldera dome and has a slightly ellipsoidal caldera rim that measures 3 km by 2.5 km, with about 200 m relief. The water depths of the caldera floor range from about 840 m to 920 m. The Kuroko-type deposit in the Bayonnaise knoll caldera occurs on the southeastern caldera floor where the caldera boundary faults intersect with a N-S-trending normal fault of the rift zone. In the deposit, many sulfide chimneys are generally less than 10 m high, and sulfide mounds are distributed around the caldera floor and on the sloping talus at the foot of the caldera wall. The deposit is buried in part by talus composed of pumice and volcanic fragments. Sulfide chimneys are still active, and inactive ones and their fragments are partly oxidized to reddish material. Chimney sulfides are mainly composed of sphalerite associated with chalcopyrite, galena, pyrite, and barite, and chemically enriched in Au up to 14 ppm and Ag up to 1400 ppm with major Zn, moderate Ba, and minor Pb, Hg, Cu, and Fe.

Jan 1, 2005

By Elizabeth McIsaac, Wylie Spicer

"In July 2016 the International Seabed Authority (the “ISA”) released a first working draft of its mineral exploitation regulations as well as the standard contract terms for mineral resources in the Area, for which stakeholder input was sought in late 2016. In January of 2017 the ISA released a discussion paper on environmental matters related to these draft regulations. The ISA is now in the process of further developing its draft exploitation regulations and standard contract terms to ensure that seabed mining is carried out in an environmentally sound way for the common benefit of mankind.As the regulator of the “Area”, the ISA can draw lessons from onshore mining regulators and offshore petroleum regulators for their experiences in legislative drafting to smoothly and safely oversee project development, implementation, and closure. However, one of the unique challenges that the ISA faces in regulating private industry is its status as an international organization and not a sovereign nation, which results in a significantly different legal relationship between the regulator and the regulated. The result is that the exploitation contract is the sole legal connection between the mining proponent and the regulator for the exploitation phrase of the project.Accordingly, in the regulatory development process, the ISA must carefully consider which rights and obligations are set out in the exploitation contract versus the regulations. This decision will dictate the flexibility the ISA will have to modernize the conduct required of mining proponents in response to changing best practices in the industry, technological progress, and advances in the understanding of the marine ecosystem. As the first working draft of the exploitation regulations sets out an initial contract period of twenty years, it is crucial for the ISA to carefully consider the rights, obligations, and procedures it agrees to in the exploitation contract, as unilateral amendment will not be possible after contract execution."

Jan 1, 2017

By G. Cherkashov

The geodiversity of seafloor massive sulfides (SMS) deposits at the slow- and ultra-slow spreading ridges is of great variety (Fouquet et al., 2010). Tectonics and magmatism are the two principal factors which control SMS formation and localization. The geological setting of SMS deposits is determined by their position relative to the rift valley and by the types of rocks hosted (Table 1). Depending on the first parameter, SMS deposits could be localized at [ ] the axial volcanic ridge or at the flank of the rift valley. Basalts, deep-seated gabbro, and serpentinized peridotites are distinguished among the hosted rocks. The outcrops of deep-seated rocks are exposed at the flanks of the rift valley. The tectonic mechanism of the lower crust and mantle rocks exhumation process is connected with very large offsets along the detachment faults, resulting in a forming oceanic core complex (OCC) (Smith et al., 2006; MacLeod et al., 2009). The SMS related to OCCs are represented by such ore clusters as Ashadze, Logatchev, Semyenov, and some others (Table 1) and are increasing steadily in number. This fact in combination with widespread OCC formation at the slow-spreading ridges (Escartin et al., 2008) and high grades of metals in SMS related to OCCs has provoked considerable scientific and economic interest in these types of deposits. It could be mentioned in this regard that the first two applications to the International Seabed Authority for prospecting and exploration of sulfides have been submitted for the areas in the spreading centres with wide distribution of the core complexes.

Jan 1, 2011

By C. H. Hobbs

A recently completed series of projects funded by the Commonwealth of Virginia and the U.S. Minerals Management Service was designed to assess the distribution of heavy minerals on the inner continental shelf adjacent to Virginia. These projects indicate that a suite of minerals of both strategic and economic interest is present. Analysis of several hundred grab and core samples shows that zircon, monazite, and titanium minerals (ilmenite, rutile, and leucoxene) occur in quantities that probably warrant further study by the mineral industry. Furthermore, side-scan sonography and shallow seismic profiles have provided information on the thickness and areal extent of the mineral-bearing sands. Possible development of the resource is enhanced by a potential use of offshore sand for beach nourishment. The results of the preliminary studies have been presented in open-file publications and oral reports in order that the mineral industry might have an up to date basis upon which to consider more exploratory work. Much of the effort south of the mouth of Chesapeake Bay was made in cooperation with and enhanced by an independent study of sand resources for beach nourishment and other needs. Preliminary review of the quantitative analyses of the heavy-mineral content of several hundred samples demonstrates that the distribution of high concentrations is non-uniform. From core data, the greatest abundances of some economic heavy minerals (ilmenite, rutile, leucoxene, monazite, and

Jan 1, 1988

By Hunsoo Choi

Internal textures of manganese nodules from Clarion-Clipperton zone of northeastern Pacific Ocean are classified into five textural zones: columnar-textured layered zone, cuspate-textured layered zone, cuspate-textured massive zone, cuspate-textured porous zone and massive- textured massive zone. Vernadite is the main constituent mineral in the columnar- and cuspate-textured layered zone. Buserite sometimes occurs in the cuspate-textured layered zone. The cuspate-textured massive zone is mainly composed of buserite. Todorokite is also associated with buserite in the massive-textured porous zone, where cuspates and globes are partially replaced by massive texture. In the massive-textured massive zone, todorokite, buserite and birnessite occur together. The analyzed elements of all zones are also classified into four elemental groups by the cluster analysis of correlation coefficients: Mn group, Cu-Ni-Mg group, Fe group and Si group. Mn group consists of Mn and K. Cu-Ni-Mg group consists of Cu, Ni, Zn, Mg and/or Ca, Na. Fe group consists of Fe, Co, Ti and/or Ca, P. Si group consists of Si and Al. Each textural zone is composed of three or four elemental groups. These four elemental groups are correlated with mineral composition, such as, Mn group with todorokite, Cu-Ni-Mg group with buserite, Fe group with Co-bearing iron-oxyhydroxide minerals, and Si group with silicates.

Jan 1, 2002

By Ivo Dreiseitl

The interaction between nodule harvester and eupelagic sediment on the seabed is definitely one of the key aspects of mining technology for polymetallic nodules which is to be studied in details. Physical properties of sediments play major role for evaluation of protection and preservation of marine environment while strength properties of sediments will come in useful for future mining operations. Cone penetration test (CPT) used for testing in situ is one of methods for investigation strength properties of sediments. The testing apparatus for CPT consists of an instrumented cone having a tip facing down and it is mounted on special underwater equipment (rus. UGI-1). UGI-1 can determine subsurface strength down to the depth interval 0 ? 1.10 m. Special IOM geotechnical cruise was accomplished in 1989 on board R/V Academic A. Karpinski within the extra test area of about 1000 km2. Thanks to UGI-1 the IOM database recorded unique strength sediment data (cone penetration resistance) from 279 seabed points of sounding at profiles 125.6 km long. Up to 35 strength data from depth interval 0-1.1m (every 3cm) were obtained from any particular testing point. As a result 279 strength charts could be plotted (two examples in Figure 1). The cone penetration resistance values can be correlated to shear strength parameters.

Jan 1, 2011