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By J. R. Woolsey

The cost of an offshore exploration project is mainly dependent on the size of the vessel engaged for the work and increases dramatically with increasing size. Of the various factors influencing vessel size, the type and size of the sampling equipment is typically the principal consideration. This scenario is particularly true of shallow sampling programs employing a vibracore system. The problem develops when certain bottom materials such as densely packed fine sand require sampling. This type of material being one of the most difficult for the standard vibracore systems, with integral core liner, to penetrate to a reasonable depth of some five to seven meters. The problem is mainly related to the excessive cross sectional area of the cutting bit required to accommodate the core liner. The typical solution has been to apply more power to the vibracore drive head which results in a considerable scale-up for the entire system with attendant increase in vessel size. In order to reduce operating cost, M.M.R.I. has developed several systems for deployment from vessels in the 20 meter range. Two systems are modifications to the basic vibracore and a third is a vibralift system. Basically, one of the vibracore units is employed where core liners are required, utilizing a special jet bit designed to reduce the cutting pressure on the bit while not affecting the integrity of the core. The other designed for core extrusion on

Jan 1, 1986

By Alan Foley

The Portable Remote Operated Drill was developed in Sydney, Australia in the 1990’s. The device is a platform for many in-situ seabed sampling and coring tasks. The range of tools developed for use in PROD’s magazine now includes gas detectors, vane testers, penetrometers and corers. This paper presents aspects of the soils testing undertaken in deepwater since 2005, focusing on testing of methane hydrates and reefal accumulations. The varied selection of tools carried in PROD’s magazines allow the unit to perform several functions from the seafloor in one deployment.

Sep 24, 2006

By Eric J. Foell, Hjalmar Thiel, Gerd Schriever

Environmental studies for the mining of polymetallic nodules (PN) from the deep sea may be traced back for some 35 years.

By Harry J. Olson

Geothermal Energy has a great potential for meeting the electrical and thermal energy requirements of many countries and territories lying along tectonically active zones within and surrounding the Pacific Basin. Energy requirements for many of these small, scattered volcanic island nations preclude development of conventional generating facilities large enough to incorporate any economies of scale. However, by attempting to discover and develop shallow, relatively low temperature, geothermal reservoirs associated with recent vulcanism on many of the volcanic islands, exploration expenditures and risks, and problems associated with the development of high temperature resources can be reduced. Exploration and development drilling for these resources can be accomplished with truck mounted rotary drilling rigs that are less costly and more suitable for operations within the island infrastructures than the conventional rigs normally used in the drilling of deep, high temperature geothermal resources. Experience over the past decade with small, modular, binary (Rankine) cycle generating units indicates that geothermal energy can provide a reliable source of baseload electricity in the amounts required and at a cost that is competitive with other alternative and conventional energy sources. Development of shall, moderate temperature, geothermal resources with small, modular binary cycle generating units can provide ideal additions to the energy sources of many of the Pacific volcanic island nations within the framework of their island economies.

Jan 1, 1991

By James C. Barker

Alaska's expansive continental shelf represents future opportunities for marine mineral development. Although today's metal prices and subsidized foreign mineral production continue to discourage industry investment in marine exploration worldwide, the longer term outlook is one of increasing costs on-shore with a dwindling land-base available on which to search for and extract minerals. Likely, the generations of the 21st century will increasingly recover their minerals from the sea-floor. Though largely unexplored, Alaska potentially represents a major port ion of the U.S. marine resources. Several factors demonstrate this. First, the Alaskan OCS is huge; 74% of the entire United States' continental shelf lies off of Alaska, and 54% of the U.S. coastline is Alaskan. Combined with the jurisdiction waters of the Soviet Far East, the Bering-Chukchi shelf is one of the world's largest tracts of shallow water. Second, Alaska is situated at the northwestern terminus of the mineral-rich American cordillera. From Chile to Alaska, major on-shore deposits of precious and base metals, ferroalloys, and industrial minerals are found in the tectonically disturbed belts of the cordillera. In 1988, the western U.S. cordilleran states produced 70% of this country's mineral output (excluding construction materials). Throughout the cordillera's entire 10,000 mile length, the rock units strike largely parallel to the coastline, but in Alaska they extend directly offshore and onto the continental shelf. Consequently, the mineral-rich terranes off of Alaska have a much more complex interaction with coastal and lit-

Jan 1, 1991

By Johnson R. Cann

Ocean floor sulfide deposits are now known from many parts of the world mid-ocean ridge system and from some seamounts. Clearly they can be expected to occur commonly on the ocean floor. However, only two or three of the known deposits appear to approach the million-ton size, and in none of the deposits has the grade been well-defined. Can knowledge of the processes that happen within the hydrothermal plumbing below deposits help define the conditions under which large, high-grade deposits form? Here I review present knowledge of ocean-floor hydrothermal processes to attempt a first answer to this question. There are three sources of information about these processes. The solutions emerging from active systems must be compatible with patterns of alteration that underlie the volcanogenic sulfide deposits of ophiolite complexes, which are slices of ocean crust thrust onto land. Both of these types of evidence can be linked by computer modelling of the exchange of heat and metals between rocks and flowing water.

Jan 1, 1988

By David Huber, John Halkyard

Deep Reach Technology, Inc. recently completed a multi-year cooperative research project for the U S Army Research Laboratory for the purposes of investigating recovery of rare earth elements from the seabed. This research led to the discovery of a potentially economical deposit in the Exclusive Economic Zone of the Cook Islands. In order to further develop this resource, Ocean Minerals LLC (OML) was formed in 2016 to explore the development of a deep-sea mining project to recover rare earth elements and scandium from the upper 10m of sediment in promising areas of the Cook Islands Exclusive Economic Zone. OML and the Cook Islands Investment Corporation signed an Agreement in 2016 giving OML exclusive rights to explore a 12000 sq km area and option rights over an additional 48,000 sq km. This poster presents the current status and activities related to this project.

Jan 1, 2017

By Teruyoshi Narita

In Japan, the Ministry of Economy, Trade and Industry (METI) commenced a research and development (R&D) project on seafloor massive sulphides (SMS) in Japan?s exclusive economic zone (EEZ) in the 2008 fiscal year. In this plan, the road map of Resource evaluation, environmental impact study, mining system technology and processing technology fields consisting of the first and second stage has been shown for the commercialization of SMS. Based on this road map, Japan Oil, Gas and Metals

Sep 14, 2011

By Michael R. Gipp

Marine Mining Inc. is currently exploring for marine alluvial gold and diamonds on a prospecting licence over a concession that covers 10,000 km2 of the continental shelf of Ghana. The boundaries of the concession extend from 0 30'W to 2 40'W, and between the shoreline and approximately the continental shelf edge north of 4 30'N. This concession extends from Kikam Beach in the west, to Senya Beraku in the east, a distance of approximately 240 km, and seaward an average of about 40 km. The concession is entirely underwater, with the exception of the estuaries of the Ankobra and Pra Rivers. Ghana has been a large source of alluvial gold, with historical production exceeding 25 million ounces. Southwestern Ghana is characterized by Precambrian rocks, which have been folded into a number of NE-SW trending synclines and anticlines. The most significant feature of the Birimian rocks is the presence of evenly spaced gold-bearing greenstone belts. They are 10-15 km wide, separated by about 90 km, separate basins filled by folded metasediments and granitoids. The rivers that enter the concession drain most of the exposed gold-bearing belts of Ghana. Given that approximately 2 km of erosion has taken place since the Mesozoic, and that gold mines on these belts boast proven reserves of over 55 million ounces, it is likely that large amounts of gold have been eroded out and carried to the sea. Coastal fractures, related to Precambrian structures reactivated during Mesozoic rifting, are responsible for the physiography of the coastal area, which consists of high-relief horsts separated by grabens that have been occupied and infilled by rivers or by finer sediments during times of elevated sea level. These fractures were loci of gold mineralization during the Precambrian, and are the source of alluvial gold in rivers confined by them.

Jan 1, 1998

By Harold Gibson, Ulrich Schwarz-Schampera, Ralf Freitag, Hendrik Mueller

INTRODUCTION Germany has a long history in marine research in the Indian Ocean. The first German scientific cruise started in 1964, followed by a series of state-sponsored research cruises between 1983 and 1995 leading to the first finding of polymetallic sulfides in the Indian Ocean. The research included regional bathymetric, geological, structural, volcanological, petrological and hydrothermal investigations along the Carlsberg Ridge and the Central Indian Ridge (CIR). Early environmental base line studies covered oceanographic and sedimentology aspects. In 2010, BGR took the initiative for the preparation of a license application for the exploration of polymetallic sulfides with the International Seabed Authority (ISA), and prospecting started in 2011 along the southern Central (CIR) and the northern Southeast Indian Ridge (SEIR) in the southwestern Indian Ocean (cruises INDEX 2011 on board R/V Sonne), INDEX 2012 (R/V Fugro Gauss), INDEX 2013/1-2 (R/V Sonne) and INDEX 2014 (R/V Pelagia). After three years of resource-oriented and environmental base line studies, BGR, in order for the Federal Ministry for Economic Affairs and Energy (BMWi), applied for an exploration license which was approved by and subsequently signed with the ISA in 2015. The license gave permission to start a detailed exclusive resource-oriented exploration program in the license area. The program includes the outline of potential ore deposits and a resource assessment but also extensive and detailed base line studies for the sustainable protection of the marine environment in the license area. The license contract has a fifteen years lifetime and may allow the application for a subsequent mining license. The exploration aims at the identification of inactive polymetallic sulfide deposits, formed below former discharge zones of hot hydrothermal fluids on the ocean floor (“black smoker” systems), by advanced and modern exploration techniques.

Jan 1, 2018

By W. C. Burnett

The land phosphate deposits of the U.S. southeastern coastal plain have long been a major factor in the world trade of phosphate rock (Fig. 1). As recently as 1979, deposits of North Carolina and Florida alone accounted for about 33 percent of the entire world's phosphate exports. This situation is changing, however. World production increased by ~9 %, yet the U.S. share was down to ~28% in 1984. A complex interaction of economic and political factors combined with increasing costs of raw materials, production, and transportation have led to this systematic erosion of the U.S. market share. Changing land-use patterns within the southeast, environmental pressures, exhaustion of shallow high-grade resources in Central Florida, and the increased pressure from expanding low-cost production in other countries throughout the world account for much of the present difficulty in the U.S. phosphate industry. Considering this depressed environment -- what are the prospects for development of offshore resources? A summary of new research on offshore phosphorite within the U.S. Exclusive Economic. Zone (EEZ), as well as an attempt to place possible development of these resources within the current economic setting, is the purpose of this presentation. We will emphasize work in progress on a major offshore deposit along the U.S. Atlantic Margin as well as new research on Pacific Ocean occurrences of phosphorite on seamounts and insular slopes within U.S. waters.

Jan 1, 1986

The chemical composition of the nodules varies with the type of manganese minerals and the size and characteristics of their nucleus, but those who have an economic interest have the following composition: Mn 29%, Fe 6% Si 5%, Al 3%, Ni 1.4%, Cu 1.3%, Co 0.25%, Na 1.5%, Ca 1.5%, Mg 0.5%, K 0.5%, Ti 0.2 0.2% and Ba 0.2% (Morgan, 2000; ISA, 2002). The Pacific Rim is an area of abundant occurrence of polymetallic nodules (Glasby et al., 1980; Morgan, 2000). According to these authors, the Pacific sea floor of the Clarion-Clipperton Zone (CCZ) is one of the most interesting areas in regard to the genesis of polymetallic nodules. Their abundance in the ocean floor is very variable, as there are places where they cover more than 70% of the ocean floor. The nodules can be found at any depth, but the highest concentrations are between 4000 and 6000m (Morgan et al., 1993). In studies conducted in the EEZ of the Mexican Pacific are those made within the project "Research on the origin, process and distribution of minerals in the Pacific ocean floor in the Exclusive Economic Zone of Mexico". Within this project Rosales (1989) conducted studies on the origin, process and distribution of polymetallic nodules, finding that a number of processes give origin to nodules, being diagenesis one of the main mechanisms of elements that contribute to the nodules. Besides hydrothermal processes that are carried near the East Pacific Rise at 21° N, inputs are contributing to the nodules metallic elements and sediments, especially in regions close to the dorsal, as a greater influence hydrogenetic processes occurs westward (Rosales and Carranza, 1990). In 1993, after cruise MIMAR II, Carranza and Rosales refer that metals such as Cu, Co, Ni, Sn, Fe, Mg, Pb, Zn and Ba may have a relationship with the East Pacific hydrothermal activity and sea currents carry these metals in solution to the Clarion-Clipperton fracture area, where there are hydrogenic metals sources (Al, Fe and Mn).

Jan 1, 2011

By G. A. Gross

Technological development in the last two decades has provided access to the deep seabed and opened a new frontier for exploration. Interest in Canada has focused mainly on study of metallic mineral occurrences and the development of a scientific data base and technology for identification and appraisal of potential mineral resources. Canadian industry and government have played an active part in the assessment of manganese nodule resource potential and the possible impact that development of these resources might have in the world mineral markets.

Jan 1, 1985

By Christian Müller, Hermann-Rudolf Kudrass, Christian Reichert

Recent studies estimate the depletion mid-point (dmp) for conventional natural gas to be reached around year 2022, and for conventional oil to be reached around year 2017. These numbers are based on simplified assumptions of unchanged demand and do not include increasing reserves from discovery of new fields and also do not include a shifting of resources to reserves e.g. due to an increasing oil price (Gerling et al., 2005). Anyhow, these prospects require conventional hydrocarbons to be substituted in the near future.

Aug 24, 2006

By Steven D. Scott

The 1991 PACMANUS Expedition (Papua New Guinea-Australia-Canada in the Manus Basin) discovered a very large (approximately 800 x 350 m) actively-forming seafloor polymetallic sulfide 4 deposit in felsic volcanic rocks of the southeastern part of Manus Basin, a 60 km wide extensional zone of basalt, andesite and dacite volcanism in the New Britain back arc. The apparent neo-volcanic zone is a 30-km long, high standing, Y-shaped edifice, which we have named Pual Ridge ("Pual" means "fork" in a local PNG dialect). The PACMANUS deposit was found by deep-tow video on Pual Ridge along the flank and adjacent valley of a dacite lava dome. Videos show large spires, chimneys and mounds with abundant fauna. Only two small samples from an active chimney were recovered. Their mineralogy is a high temperature assemblage of chalcopyrite, bornite, tennantite, sphalerite or wurtzite and anhydrite. The bornite and tennantite and silver rich. Gold values for the two samples are 2 and 10 ppm. A pronounced methane and particulate plume was traced in the water column for 14 km to the northeast of the PACMANUS deposit. Other deposits of unknown size are nearby. The deposits of Pual Ridge and their surrounding volcanic rocks have close similarities to ancient massive sulfides of Archean to Phanerozoic age in Canada and Australia.

Jan 1, 2011

By C. R. Pearce, B. Murton, S. Howarth, P. Lusty

"With the expansion of “green” energy technologies, the demand for the critical raw materials required to sustain this growth is increasing. Many E-tech elements, including tellurium (Te) and rare earth elements (REEs), suffer from high supply shortage risk and the need for more diversified metal supply routes is driving research into alternative resources. Hydrogenetic ferromanganese crusts, seafloor deposits of Fe- and Mnoxyhydroxides that form from the direct precipitation from seawater, present a potentially important future source of E-tech elements. With growing interest in the potential wealth of these deposits and the issuing of permits for deep-sea mining and exploration, more work is underway to understand the nature of ferromanganese crust deposits, their elemental concentrations and distributions, and the potential impacts of mining activities.This research focusses on the formation of ferromanganese crust deposits and processes that control the extreme enrichment of elements such as Te, Co and REEs. The crusts were systematically sampled and mapped between ~ 1000 – 4000 m depths using ROV ISIS, from a range of environments, substrates and morphologies from Tropic Seamount (NE Atlantic) in order to determine the seamount-scale factors that control major and trace elemental concentration variations. These factors include depth, surface roughness and micro-bathymetry, location relative to long-term mean current direction and energy, influence of tidal energy dispersion across the seamount, sediment supply, substrate lithology, biological productivity and phosphatisation. The study analyses trace-element characteristics of 100 ferromanganese crust samples alongside standard reference materials NOD-A-1 and NOD-P-1 (US Geological Survey manganese nodules). At this initial stage, we report results from whole rock acid digestion and ICP-MS analyses."

Jan 1, 2017

By Daniel E. Walsh

The recovery of most minerals, which are amenable to gravity concentration, is standardly determined by accurate sampling and assaying. .With respect to particulate - gold ores, sampling and assaying are still the convention, but the accuracy and reproducibility of these operations are much discussed and debated points. Evaluation of gravity concentrators by conventional sampling and assaying techniques is very time consuming, costly and may introduce a large amount of uncertainty into the results due to the particulate nature of placer gold. These problems are not unique to placer gold ores and apply to any low grade ore with particulate values. A gravity concentrator evaluation process developed by MIRL employs the use of neutron activated gold (198Au) and radiation detection circuits which monitor the concentrator's product pulp streams. Concentrator recovery is determined from the ratio of the number of gold particles detected as passing into the concentrate to the total number of gold particles detected over all monitored pulp streams. This system eliminates the experimental errors introduced by sampling, sample reduction, and assaying and allows recovery to be evaluated for gold particles of specific sizes, shapes, and flatness. This system enjoys its greatest utility where a large number of tests are to be run in order to evaluate a concentrator over a variety of operational settings, i.e. factorial designs, and allows accurate testing of concentrators operated in closed circuit systems. Beginning in 1984, MIRL conducted radiotracer studies of unit processes, which included jigging, static wedge wire screening, elutriation, and concentration with compound water cyclones.

Jan 1, 1989

By S. Hölz, M. Jegen, K. Reeck, A. Haroon

Past investigations of seafloor massive sulfides (SMS) focused on actively forming sites. New technologies are needed to explore for SMS deposits which have finished their active phase and are possibly covered by sediments or lava. For this purpose the new marine transient electromagnetic (TEM) induction system MARTEMIS was developed by GEOMAR. The system was used for investigations in the Tyrrhenian Sea (Palinuro Seamount) and at the Mid-Atlantic Ridge (TAG area) and proved to be suitable for operations at shallow (~600m) and great water depths (~3600m) in steep and difficult terrain. Calibration measurements in the water column demonstrate that it is possible to acquire high quality data, which is fit to be evaluated in terms of inversions. However, these calibration measurements also demonstrated that great care has to be taken in the design of such an inductive coil system, because relatively small metal structures attached to the system may lead to significant static distortions in the measured transients. The interpretation of TEM data acquired at the Palinuro Seamount show a conductive layer in the vicinity of a previously drilled, buried SMS occurrence and serve as proof of principle of the system. Results also indicate that the conductive SMS unit is indeed a confined layer with limited thickness between 3 – 5m, which was not known from previous drilling. In a similar manner, results also hint at an unknown mineralization at depth in a second area of the Palinuro Seamount. Investigations by TEM measurements were accompanied by measurements of the ambient electric field (→ self-potential) and seafloor temperatures with a heatflow probe as well as direct sampling with a gravity corer. The areal coverage of measurements and sampling allow for a greatly enhanced view of the structure.

Jan 1, 2018

By Karsten Hagenah, Tor Jensen, Jens Laugesen, Øyvind Fjukmoen, Lucy Brooks

This paper describes operational environmental threshold levels for exploitation of mineral resources in the deep sea. Such criteria are needed to be able to monitor and control deep sea mining with respect to the stringent environmental requirements that are needed. It is recommended to use existing environmental threshold levels for comparable activities where such are existing. Fields of application are mainly but not exclusively seabed mining operation activities under the governance of the International Seabed Authority (ISA). The threshold levels and limits mentioned in this paper are proposed recommendations based on other activities than seabed mining but are a proven and accepted approach in other maritime industry activities. An example of such other activities with proven and accepted environmental threshold levels are Oil & Gas exploitation activities in the sea. Background The first exploitation of mineral resources is coming closer. At the moment regulations for exploitation for mineral resources in the Area are being developed by the International Seabed Authority (ISA). The ISA regulations will contain the framework related to environmental monitoring of exploitation. However, the regulations will not contain operational environmental threshold levels for the Contractor.

Jan 1, 2018

By Tony van der Steen

Subsea mining system are designed for the following, principally different, tasks: Dreding - The destruction and removal of seabed sediments overlaying the bedrock. Cleaning - The competence of the system to systematically remove the deposits from an undulating hard bedrock with irregular pulleys, channels and fissures. Factors that influence the choice of dredging equipment for a specific project are project requirements such as environmental conditions, location and water depth. However, the most important selection criteria are soil conditions. As a consequence, possible dredging systems, must be evaluated for the following, principally different, characteristics: Dredging proficiency - The destruction of the strata by the equipment. System stability - The capability of the soil to support the subsea equipment The above parameters are determined by the strength characteristics and the bearing capacitv_ of the soil. The author describes the processes involved in excavating the subsea deposits and (transporting the gathered soil as a water-soil mixture to the surface using different excavation and transport methods.

Jan 1, 1998