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By Yuta Yamamoto

Seafloor massive sulfides (SMS) which contain Au, Ag, Cu, Zn, and Pb have been interested in as a target of commercial mining these 15 years. Japan has large potential of SMS and a national R&D project for the mining has been active these 5 years. However, the economy of SMS mining is very bad, because the waste tailing disposal cost is very expensive in Japan. A slurry flushing method is experimentally examined in this study for the improvement of the economy. During the flushing, because of density difference between the metal-rich ore and the waste rock, a kind of gravity separation is possible. The results suggest a possibility of the actual application.

Sep 14, 2011

By Tetsuo Yamazaki

Seafloor massive sulfides have been a subject of interest for profitable commercial mining these ten years. Because of the higher Au, Ag, and Cu contents, they have received much attention as immediate commercial mining targets by private companies and nations. Some of them already proposed the technologies necessary for the commercial mining. However, the technologies for survey, excavation, lifting, and ore dressing have not yet well been examined from viewpoint of the economy. In this presentation, the authors present some key factors and improvements for better economy in the mining.

Jan 1, 2010

By Ian B. Clark

In October-November 1993, the Centre for Cold Ocean Resources Engineering, Memorial University of Newfoundland and University of Victoria jointly carried out reconnaissance surveys at Pine Cove, Baie Verte, Newfoundland. Pine Cove is the site of a multi-year study examining the environmental impact of a shallow water small-scale marine placer gold mining operation. The reconnaissance survey data collected will be used to develop a multi-year environmental effects monitoring (EEM) program for Pine Cove, Baie Verte, but more generally an EEM protocol for shallow water small-scale marine placer mining, which meets the requirements of Canadian government regula¬tors such as Environment Canada and the Department of Fisheries and Oceans. The Pine Cove mining operation is currently scheduled for the summer of 1995, and will use two mining methods: a hydraulic suction dredge in shallow water (<10 meters) operated by a scuba diver, and a hydraulically actuated clamshell dredge in deeper water (-30 m). A centrifugal concentrator will be used to extract the heavy minerals from the mined marine sediments, and the tailings will be returned to the sea floor via a suspended discharge pipe. The reconnaissance work at Pine Cove included geophysical, geochemical, oceanographic and biologi¬cal surveys, providing data which will enable prediction of the potential environmental impacts of the proposed mining operation. The geophysical surveys showed the sea floor to be covered by varying

Jan 1, 1994

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&apos;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&apos;s diamond coast.

Jan 1, 1998

By Youngtak Ko

The northeastern Pacific shows the highest nodule abundance among the oceans in the world, and thus has been drawing international attention for deep-sea manganese nodule development. The objectives of this study are to construct database using geostatistics and geographic information system (GIS), to quantify rating value using probability and statistical methods, to suggest suitable sites for manganese nodule development, and to verify results using three statistical approaches. The copper and nickel contents of the nodules were determined by chemical analysis. Factors related to slope, aspect, water depth, and topography were obtained from multi-beam echo sounding data. The transparent layer thickness was determined using a sub-bottom profiler. The probability method was used to calculate each factor&apos;s rating, and the layers for different factors were summed to produce the development potential index (DPI). Result maps were constructed for manganese nodules development. The distribution pattern of DPI showed to be controlled of nodule abundance and metal contents. Verification was performed by comparing the results with sampling data in three ways: success and prediction rate, linear regression, and test of independence.

Sep 14, 2011

By Leonhard Weixler, Peter Platzek

The Company Bauer Maschinen is very well known in the field of specialist foundation equipment. In the diaphragm wall market, we have experiences both in manufacturing and executing projects all over the world since 1984. We have a population of more than 300 units working all over the world in all climate and soil conditions. Especially for hard soil and rock conditions, we have developed several cutting tools and systems to optimize the performance, e. g. the “flipper tooth” Besides the execution of land based foundation projects, we have performed our firs offshore project with the trench cutter in 1994. Our task was to take samples out of the alluvial soil off the coast of Namibia in a water depth of max. 200 m. We converted a drill vessel and launched the cutter thru the moon pool. The samples had a cross section of 3,40 m² and a max. depth of 5 m. They were used to estimate the content of diamonds. The first time, we reached the seabed of the deep sea was together with our seafloor exploration rig MeBo, where we can take cores up to a length of 160 m in a maximum water depth of 4000 m. With our customer MARUM, we have done several expeditions since 2005. The last expedition took place in the Black Sea to explore gas hydrates.

Jan 1, 2018

By Leonhard Weixler, Peter Platzek

The Company Bauer Maschinen is very well known in the field of specialist foundation equipment. In the diaphragm wall market, we have experiences both in manufacturing and executing projects all over the world since 1984. We have a population of more than 300 units working all over the world in all climate and soil conditions. Especially for hard soil and rock conditions, we have developed several cutting tools and systems to optimize the performance, e. g. the “flipper tooth” Besides the execution of land based foundation projects, we have performed our firs offshore project with the trench cutter in 1994. Our task was to take samples out of the alluvial soil off the coast of Namibia in a water depth of max. 200 m. We converted a drill vessel and launched the cutter thru the moon pool. The samples had a cross section of 3,40 m² and a max. depth of 5 m. They were used to estimate the content of diamonds. The first time, we reached the seabed of the deep sea was together with our seafloor exploration rig MeBo, where we can take cores up to a length of 160 m in a maximum water depth of 4000 m. With our customer MARUM, we have done several expeditions since 2005. The last expedition took place in the Black Sea to explore gas hydrates.

Jan 1, 2018

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 J. Robert Woolsey

This paper provides certain Southeastern coal-burning utilities with an economic strategy for complying with the sulfur dioxide emission standards set firth by the Clean Air Act Amendments of 1990. The strategy takes advantage of the occurrence of vast quantities of manganese nodules on the Blake Plateau offshore Georgia and the Carolinas, a commodity which as been proven to be a highly effective dry sorbent of sulfur dioxide. Using existing technology, manganese nodules could be mined and transported via barge directly to power plant sites, where they would be used as filter material for cleaning sulfur dioxide from the effluents of coal-fired power plants. Completely sulfated filter material could be treated for the extraction of by-product metals such as cobalt, copper, nickel, and manganese. The strategy may well be enhanced by the occurrence of ore grade phosphate rock in the same area of the Blake Plateau. This phosphate rock could be simultaneously mined to effect a reduction in production costs if it is found to be suitable for use as either a direct application fertilizer or as an acidulated superphosphate fertilizer. The manganese nodule-based strategy offers a retrofitting solution for existing power plants that would minimize the capital costs for compliance with the Clean Air Act Amendments and has the added advantage of providing a number of other metal or fertilizer by-products.

Jan 1, 1992

By Roy Nilsen, Aravinda Perera

With the exponential growth of demand for minerals and need for diversification of supply channels, deep-sea mining is rapidly becoming inevitable. Productivity of underwater mining technology is salient to justify the deep-sea explorations. Methods for enhanced productivity of mobile mining equipment in a system level are investigated in this paper. Lessons learnt from the land-based mining has been the basis of this investigation. In general, mining productivity can be enhanced in two ways; firstly, by maximizing the amount of recovered material per unit time and secondly, by minimizing the cost of operation per unit material. Equipment that enable faster excavation, loading and transport in the seabed contributes significantly in increasing the amount of slurry per unit time. Improved mean time between failures (MTBF) of mining equipment will reduce the operational down time, thereby, contribute to maximize the amount of mined material per unit time. Several factors influence the operational cost minimization per ton of slurry. Higher efficient motor drive systems including the motor and PWM-fed inverter not only will save power but also will emit lesser heat thus the heat management can be less complex. This leads to more compact drive systems that allows higher power density, thus increased payload weight per empty vehicle weight. An energy storage method in the form of an utracapacitor in the electric drive system will also save the energy supply from the upstream.

Jan 1, 2018

By Steven D. Scott

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

Jan 1, 1992

By E. Moriguchi, K. Tamaki, A. Okuda, K. Iizasa, C. Honsho

The northern Izu-Ogasawara Arc is characterized by an abundant distribution of submarine calderas along the volcanic front to the back-arc rift zones. In many of these calderas hydrothermal activities are observed. Among these calderas, hydrothermal ore deposits with economically feasible quality and amounts are hosted at two calderas, the Myojin Knoll Caldera and Beyonnaise Knoll Caldera. We conducted two research cruises in 2005 and 2006 to investigate further hydrothermal activities and ore deposits in these calderas and to complete the geological and geophysical mapping in the area. We discovered a strong signature of hydrothermal activity in the Myojin-sho Caldera using AUV capabilities. Newly obtained geological and geophysical data clarified the relationship between back-arc rifting tectonics and hydrothermal activities in the area. Five calderas (two of them newly found) and numerous (>200) volcanoes are mapped in the area. Complete SeaBeam coverage showed a distinct feature of the back-arc rifting activity and its relationship to the submarine calderas on the volcanic front. The back-arc rift zones composed of four segments separated by E-W trending volcanic ridges. Three of the calderas are located in the rift zone and are heavily deformed by the rift normal faulting that typically trend NNW-SSE. As the Beyonnaise Caldera is located in a swarm of faulting zones at the eastern end of the back-arc rift, the formation of the hydrothermal ore deposits found in the Beyonnaise Caldera are apparently affected by these faulting activities. Newly found submarine calderas are located in the rifting zone and are heavily faulted.

Sep 24, 2006

By H. L. Gibson, U. Schwarz-Schampera, Mark Hannington

Ancient ore deposits provide important clues for the understanding of the origin and distribution of modern submarine hydrothermal systems. An analysis of the formation conditions, tectonic settings, and preservation of ancient seafloor mineral deposits from the recent geological past to the late Archean sheds light on the time-space relationships and diversity of mineral deposit types likely to be found in the modern oceans. Microplate tectonics that characterized ancient ore-hosting greenstone belts were strikingly similar to those active in volcanic arc environments of the western Pacific today. In such complex settings, oblique collisions, opposing subduction zones, and rapid changes in stress regimes (e.g., from compressional to tensional and back to compressional) were common, causing juxtaposition of diverse styles of mineralization. The world-class base metal deposits of the late Archean Abitibi greenstone belt of Canada, for example, were formed within a relatively short time span of ~20 m.y., in response to successive arc rifting, back-arc basin development, and exhumation of accretionary complexes along major arc-parallel crustal-scale faults. Similar processes and environments are important settings for metallogenesis in modern submarine volcanic arcs. Active marginal basins of similar size and representing similar stages of evolution are well represented in the western Pacific today and contain a similar suite of mineral deposit types. Examples from the eastern Manus Basin and adjoining New Ireland Basin (PNG) and in the Lau-Tonga-Kermadec arc-backarc system illustrate these similarities. Certain gold-rich volcanogenic massive sulfide deposits at the southern margin of the Abitibi greenstone belt (e.g., Bousquet and LaRonde deposits in the eastern Blake River Gp.) may be important ancient analogs of newly discovered gold-rich black smoker deposits found along the active fronts of today&apos;s submarine volcanic arcs.

Sep 24, 2006

By Alexander Malahoff

The study of why and how life survives in the Extreme environment is a major frontier of science today. Extremophiles are organisms that require extreme environment including high temperature, pH, pressure and salt concentration, or low temperature, pH, nutrient concentration, or water availability. Their common habitats are geothermal vents, pools, lakes and craters of active volcanic regions, such as those of New Zealand, Japan, Kamchatka, Yellowstone USA or the hydrothermal vents of the ocean ridges and submarine volcanoes. These settings are accessible by foot, boat, helicopter, or submersibles. This presentation examines the geology, chemistry of geothermal sites of New Zealand, including the active volcano, White Island, Yellowstone, the submarine volcano Loihi in Hawaii, and sections of the mid-ocean ridges. Designing process and construction of Extremophilic sampling and bioreactor systems used in the study of Extremophiles will be discussed. The driving force behind the research of extremophiles is not only the fundamental science, but also biotechnological potential associated with these microorganisms and their cellular products. The University of Hawaii?s Marine Bioproducts and Engineering Center (MarBEC) is laying the foundations for such new industries.

Jan 1, 2001

By A. M. Olivarez

The elucidation of the theory of plate tectonics has provided a conceptual framework for understanding the formation and distribution of different types of ore deposits. For example, we now recognize that certain kinds of mineral deposits are generally associated with a particular type of plate boundary (i.e., massive sulfides often occur along divergent plate boundaries, whereas porphyry copper deposits are typically found along convergent boundaries). During certain geologic time periods, plate reorganization events have changed the relative proportion of different types of plate boundaries. Corresponding changes have been observed in the abundance and distribution of ores deposited during these times. The present study examines the temporal aspects of this relationship; i.e., do plate reorganization events play an active or passive role in ore formation? In other words, do plate reorganizations simply provide a more favorable tectonic setting in which ore formation can occur over significant time periods, or are they directly linked to the mineralization process? We have examined this question by comparing regional tectonic histories with the ages of known massive sulfide and porphyry copper deposits. Because these deposits, in particular massive sulfides, form as a result of hydrothermal activity, we have also compared regional tectonic histories with proxy indicators of this process in the marine sedimentary record. These indicators include increased mass accumulation rates of Ca, Fe, Mn, and opal, characteristic changes in the Sr/Ca and Mg/Ca ratios of biogenous carbonates, and shoaling of the carbonate compenstion

Jan 1, 1988

By V. Zaykov

The Urals massive sulfide deposits are concentrated in Silurian -Devonian fold belt extending for 1500 km with length from 50 to 150 km. By paleodynamic reconstmction it is established that they were formed in submarine parts of island arcs, in inter arc and back arc basins, marginal seas. When "black smokers" were found in rift zones of present oceans, problem searching their analogues in the Urals Paleozoic complexes was arisen. For solving this problem and demonstration of seafloor origin of massive sulfide many quarries and drill cores were carefully sketched and studied. Particular attention was given to correlation between ores and synchronous sedimentary rocks and fossils. Various laboratory methods were used for comparing sulfides from ore hills with ore-clastic sulfides.

Jan 1, 1993

By Robert R. Tarver

A long history of gold production at Nome, Alaska has resulted in long term interest in the nearshore environment as a production target. Mining by Western Gold Exploration and Mining Company offshore of Nome yielded approximately 100,000 troy ounces of gold in the period 1986 through 1990. This study was designed to determine the relationship between heavy minerals, sediments, and gold concentrations which occur in the upper meter of sediment offshore of Nome. Standard procedures were implemented for grain size analysis, heavy mineral separations, and heavy mineral frequency determination.

Jan 1, 1991

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 Carolita U. Kallaur

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

Jan 1, 1992

By 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