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By Seung-Kyu Son

This study was investigated about physico-chemical parameter such as water temperature, salinity, inorganic nutrients and total organic carbon (TOC). CTD (Model: Sea-Bird 911 Plus) castings were carried out on two transects in the northeast equatorial Pacific Ocean. As a part of the Korea Deep-sea Environment Study (KODES), inorganic nutrients and TOC were determined at 41 stations located from 131° to 136°W along 10.5°N and from 17° to 5°N along 131.5°W (Fig. 1). We particularly chose KODES Long-term Monitoring Station (St. KOMO) to observe for the annually environmental baseline study in the contract area. [ ]

Jan 1, 2005

By Gary J. Massoth

Wherever hydrothermal fluids vent from the seafloor they will buoyantly rise (up to 100?s of meters) while mixing with seawater before attaining density equilibrium and dispersing laterally as neutrally buoyant plumes commonly 50 to several 100?s of meters in thickness and with order-of-magnitude or greater breadth. Although these plumes are typically >10,000-fold dilutions of vent fluids they can be reliably detected using sophisticated physical sensing and chemical techniques. Hence, hydrothermal plumes are spatially large targets compared to the actual sites of seafloor fluid discharge and resulting mineralization. For this reason plume prospecting techniques evolved over the past 20+ years have been widely used to systematically explore over 10% of the 60,000-km-long system of mid-ocean ridge (MOR) spreading centers for hydrothermal activity. While plume detection and gradient mapping can be used to home in on venting sites, plume chemical signatures provide additional insight regarding the nature of the fluids being discharged on the seafloor. We have applied the systematic plume prospecting techniques developed on MORs to the volcanic frontal arc setting as part of the NZAPLUME (New Zealand American PLUme Mapping Expedition) surveys. NZAPLUME I in March 1999 marked the first systematic reconnaissance of any intra-oceanic arc for submarine hydrothermal activity. Seven of thirteen previously mapped volcanoes that comprise a 260-km-long section of the southern Kermadec arc northeast of New Zealand were confirmed to be hydrothermally active. On average, one hydrothermally active volcano was found along each 35 km of arc front, a rate comparable to slow- and intermediate-rate spreading MORs. During NZAPLUME II in May 2002, thirteen previously unknown volcanoes and 8 satellite cones were first swath mapped for bathymetric detail and then surveyed using plume prospecting techniques. Three active venting sites were discovered along this 580 km-long arc section, bringing the total to 10, or 39% of 26 volcanoes surveyed overall, still an appreciable frequency rate for venting sites compared to MORs. While only chemical results for NZAPLUME I are available, the arc plumes characterized so far are chemically diverse and rich compared to MOR plumes. This diversity and enrichment was most evident as ultra-high concentrations of CO2, sulfur gases (St = SO2 + H2S), and Fe within plumes over several volcanoes. We suggest the fluids discharging from the seafloor at these sites are volcanic fluids, i.e., hybrid fluids comprised of MOR-like hydrothermal fluids evolved from seawater-rock reaction and fluids exsolved from magma as acid volatiles and liquid brines.

Jan 1, 2002

By Cees van Rhee, Rudy Helmons

INTRODUCTION Seafloor Massive Sulphides are typically found near the oceanic ridges at larger water depths (>1km). The physical properties of SMS, as shown in table 1, are comparable to the properties of weak rock. One of the technical challenges to enable extraction from these locations is the cutting or excavation process. Experiments have shown that the energy needed to excavate the material may increase with water depth (Alvarez Grima et al. 2015). Besides that, it is demonstrated that rock that fails brittle in atmospheric conditions can fail more or less in a plastic fashion when present in a high pressure environment, as would be the case at large water depths. The goal of this research is to identify the physics of the cutting process and to develop this into a model in which the effect of hydrostatic and pore pressures is included. The cutting of rock is initiated by pressing a tool into the rock. As a result, at the tip of the tool a high compressive pressure occurs, which leads to the formation of a crushed zone. Depending on the shape of the tool and the cutting depth, shear failures might emanate from the crushed zone, which will eventually expand as tensile fractures that can reach to the free rock surface. Through this process intact rock will be disintegrated to a granular medium. For an overview of the process (figure 1). Additionally, the presence of water in the pores of and surrounding the rock influences the cutting process through drainage effects. The most relevant effects are weakening when compaction and strengthening when dilation occurs in shearing and tension. Deformation of the rock causes the pore volume to change, resulting in a under or over pressure. As a result, the pore fluid needs to flow. The magnitude of the potential under pressure is limited through cavitation of the pore fluid, limiting further reduction of the pore pressure (figure 2). The drainage effects cause the rock cutting process in a submerged environment to show a stronger dependency of both the hydrostatic pressure as well as the deformation rate (figure 3).

Jan 1, 2018

By Mikhail D. Ageev

The paper concerns with some questions of Autonomous Underwater Vehicle (AUV) control system design, which allows a motion at rough undersea terrain. The AUV advantages reveal itself completely during exploration of such objects as seamounts and reefs area. These objects are characterized by steep slopes (30 degrees and above) and chaotic situated obstacles (rock debris, pinnacles, escarpments). Uses of other technical facilities for operating in such formations are difficult, dangerous or impossible. These regions take an interest due to the presence of iron-manganese crusts. Modern AUV can estimate density of mineral by means of still camera or video recorder. For this reason the vehicle has to move with the distance of 3-5 meters from seabed. Under such conditions micro- and mesorelief presents a considerable danger for AUV. The AUV can bypass underwater obstacles in the various ways. However, in any case AUV motion will be characterized by intensive maneuvering on various speeds (from 0 up to 1.5 m/s), circular change of tractive force vector and, hence, a circular flow about the hull. So, AUV is equipped with the propulsion system, which provides free modes of motion.

Jan 1, 2003

By David G. Jones

Radiometric surveys of the beach and nearshore zone of the Dutch Frisian Islands have identified sands enriched in heavy minerals. The areas of heavy mineral concentration have been mapped in detail using a state of the art towed gamma-ray detector, which gives improved sensitivity through the use of new detector materials and improved data processing techniques. The detector provides continuous measurement of sea floor radioactivity (and of a number of other parameters) and can be used simultaneously with other survey techniques, such as echo sounding, sidescan sonar and shallow seismic profiling. It enables a rapid, and cost effective, assessment of the surface distribution of heavy minerals to be made. The heavy mineral suite includes magnetite, ilmenite, garnet, rutile and zircon. These minerals contain 1-3 orders of magnitude more U and Th, in terms of their activity concentrations, than the accompanying light minerals (mainly quartz). Since the heavy mineral composition of the sands appears to be relatively constant along the Dutch Frisian Island chain, the U and Th concentrations can be used to provide a quick estimate of the heavy mineral content. The sea floor radiometric measurements allow sediment sampling for more detailed analysis to be highly targetted. The zones of heavy mineral enrichment are generally sub-parallel to the coast and are usually confined to water depths of 5-10 m. There is a close correlation with sand bars on the shoreface, the highest radioactivity typically occurring just seaward of the crest of these features. As well as being used for heavy mineral exploration, similar radiometric methods can be applied to mineral processing. Gamma-ray detection systems can be used to provide rapid analysis in the process stream enabling on-line grade control and optimisation of processing, from excavation of mineral sands to the final products.

Jan 1, 1995

By Jiahua Pan, Yanxiong Mei, Shuqin Liu, Rongfu Pei

Growth characteristics of Co-rich crusts from the Western Pacific have been approached. The thick crust shows 3 structural layers: compact upper layer, porous middle layer, and compact lower layer. The middle and lower layers have obviously different microscopic structure, color, and luster. Preliminary study of Calcareous nanofossils in one crust shows that the crust began to grow since Paleogene. The porous middle layer was formed from late Miocene to late Pliocene (Ca. 0.5 ~ 11.9Ma) and the compact lower layer was formed from late Paleocene to late Oligocene (Ca. 56.3 ~ 23.2Ma). The sedimentary hiatus of a 14.26Ma was observed between the middle and lower layers. The boundary between them to be Oligocene/Miocene (O/M) shows an important message on growth age.

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 Chan Min Yoo, Kiseong Hyeong, Inah Seo

INTRODUCTION One of the major concerns for deep seabed mining is its environmental impact, from the disturbance of benthic communities due to the mining activity to the disposal of mine tailings back to the ocean. Yet a significant amount of waste materials would be produced from the on-deck processing on the mining platform, all the materials that produced on the mining platform are to be shipped to the land unless the related regulation and guidelines are developed by IMO and ISA (ISA, 2018). Still, ecotoxicology data for the deep seabed minerals from case studies in deep-sea tailings disposal (DSTD) and submarine tailings disposal (STD) sites are lacking and all other related aspects are also largely unknown. This year, the Republic of Korea has started a research project for the more comprehensive understanding of chemical and physical properties of mine tailings from the on-deck processing and the possible environmental impacts on the marine organisms after its disposal. Based on the scientific data collected from this project, Korea would be able to make recommendations for the methods and technical standards for the deep seabed mining discharges. The subjects of this project are threefold: to understand the physical/chemical properties of the tailings, to model the dispersion of particulates after the disposal, and to assess its impact on the marine ecology. Laboratory Experiments Producing Mine Tailings First, the possible waste materials are produced by mimicking the collecting and dressing processes at sea. The polymetallic nodules (PN) would be mined by using a collector lifting the crushed nodules out of the bottom sediment, and the bottom water, accompanying sediment, and the fine nodule particles which are too small to be recovered would be discharged to the ocean and thus are considered as tailings (Schriever and Thiel, 2013). In the laboratory, PN is crushed into the fragments smaller than 2 cm, abraded in the water using the rock mill, and then sieved to obtain the fine particles to be disposed.

Jan 1, 2018

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 combine at appropriate conditions of temperature and pressure and are found in 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 ocean basins. The stability of gas hydrates depends on the critical combination of high pressure and low temperature (0 - 17 bars, 0 - 25°C), which in turn is dependent on the mix of gases from which the mineral is formed. As the critical parameters can be altered by deposition, erosion, slumping, formation or melting of ice cover, rise and fall of sea level, and sudden temperature changes induced by tectonic activities, current flow, or volcanisms, the gas hydrates tend to be very unstable. The Indian offshore is promising for 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 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 Bottom Simulating Reflectors (BSR). The study indicates that a minimum water depth of 750 m is required for the formation of gas hydrates, above which the chances for gas hydrate occurrence appear minimal despite other favorable conditions like organic-rich sediments, etc. Single-channel seismic analog records (Gupta et al., 1998) indicate that the Western Continental Margin of India (WCMI) offers a greater promise for gas hydrate occurrences, particularly with regard to the number of BSRs traced on the analog records as compared to earlier surveys.

Jan 1, 2005

By Jan Willem van Bloois

IHC Merwede is world market leader in the construction of specialist dredging equipment; it is a company with a rich history. The Netherlands is a coastal western country for which water management is a very important issue. Without the enclosure of the coastal areas with dikes and dunes almost two third of the Netherlands would be flooded. These activities are mostly performed by the dredging industry and are the foundation of the dredging industry as it is today. Besides land protection this industry also carries out infrastructure maintenance and performs land reclamation projects. In essence the dredging industry is specialized in horizontal excavation activities and operations in shallow waters with the purpose of gathering bottom sediments and disposing it at a different location. The development is that the activities are moving to deeper waters to a depth of up to 150m. A few years ago IHC Merwede received a request to perform the shallow water excavation techniques at a depth of approximately 2000 meters for the deep sea mining market. In response to the increasing number of requests for deep sea dredging and mining application solutions, IHC Merwede combined all of its activities in this sector to create a new, specially equipped operational unit, IHC Deep Sea Dredging & Mining (IHC DSDM).

Jan 1, 2010

By William D. Siapno

Mining the deep ocean by the year 2000 may seem far fetched. The year 2000 is but a decade away, a scant 10 years. Remember, the youngsters of today will grow up in a little more than a decade and rebut the wisdom of the ages, especially the traditions of their elders. Rude perhaps, but none the less a fact of life. Ocean mining exhibits many of these same traits. We should all brace ourselves for some rude shifts in our rapidly moving society. Major shifts in economics, politics, and social orders are the rule of the day. Communism is in retreat, our own economic structures chaotic. So in this moment of cataclysmic change, a shift in the international market place of mineral resources should not be a great surprise.

Jan 1, 2011

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 Toru Yamasaki

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

Jan 1, 2017

By Mark D. Hannington

Results of the R/V Sonne Cruise (Edison) to the Tabar-Feni Arc from March 11 to April 5, 1994, a joint German-Canadian research cruise aboard the vessel R/V Sonne, undertook detailed mapping of the Tabar-Feni island chain, Papua New Guinea. The Tabar-Feni chain is host to several large porphyry stocks and epithermal gold deposits, including the giant Ladolam gold deposit on the island of Lihir (minimum 19 million oz. Au). The principal objective of the cruise was to map the seafloor in the vicinity of recently active alkaline volcanic islands in the Tabar-Feni chain and to characterize the tectonic setting of large high-level porphyry and epithermal gold deposits in the region. Additional work was carried out on shallow-water hot springs associated with mineralized geothermal systems on the volcanic islands. Complete sets of 1:50,000 scale (20-m contour) maps of the seafloor were produced for each of the four island groups (Feni, Tanga, Lihir, Tabar). The Lihir group was the most active and the most interesting. At least 4 (and probably 6 or 7), previously unknown volcanic cones were discovered within about 10 miles south of Lihir. The volcanoes are clearly very young and appear to have erupted along extensional faults produced by regional plate rotation. This recent volcanic activity appears to reflect recent forearc extension and represents the southward propagation of volcanic activity towards New Ireland. One volcanic cone at 1,490 m water depth is hydrothermally active, with very large areas of diffuse venting (100-200 m across), densely populated by beds of giant clams (probably calyptogena). Other vent-specific fauna are also present, including crabs, snails, sulfide worms, scale worms, limpettes, etc. The clam beds sit on a crust of hydrothermally baked and indurated, sulfidic, hyaloclastite-rich muds. The mineralization consists mainly of fine-grained disseminated pyrite and amorphous Fe-sulfides. A second, much larger cone at a depth of 1,070 m is capped by massive vesicular lavas which are intensely fractured and mineralized. Abundant sulfides and amorphous silica occur in stockwork-like veins which

Jan 1, 1994

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

By Michael J. Cruickshank

A workshop to examine recovery systems for selected strategic and critical materials in the U.S. National Seabeds for the National Defense Stockpile in the 21st Century was held in Hawaii September 26-28, 1991, sponsored by the National Science Foundation and the Marine Mineral s Technology Center. The National Defense Stockpile of critical and strategic mineral commodities is presently in a deficit position of more than 7.5 billion dollars. Current domestic reserves of some commodities are limited or nonexistent. As defined by the U.S. Bureau of Mines, "Reserves are select resources . . . which at the time of classification, can be mined at a profit." Occurrences of these minerals have been discovered offshore within U.S. jurisdiction. If the technology could be developed to convert these resources into usable ore reserves, our dependence on foreign ores could be greatly reduced. Preliminary estimates indicate that a ten-year program of ore reserves definition, with appropriate technical developments to demonstrate a recovery system, could cost less than half the amount authorized for stockpile acquisition in FY 1989 alone.

Jan 1, 1991

By Michael J. Cruickshank

Marine minerals are more than an academic curiosity as they represent the most significant global source of mineral materials for economically and ecologically sustainable development for the future. Minerals research is traditionally carried out by industry and thus, in the United States at least, applied research in marine minerals may not get the share of government funding or attention that more exotic programs for space exploration or future global disasters engender. Two recent events have significantly changed the status of marine minerals. Discoveries made in the last thirty five years indicate that the potential for mineral occurrences in the oceans and seabeds, area for area, is as high as for terrestrial lands. On this basis the global mineral resource base has been recently increased by a factor of four of which three quarters is underwater. The recently enacted Law of the Sea has mandated what is probably the most far reaching re-distribution of natural resources in human history, and has resulted in a peaceful subdivision of seabed jurisdictions between the coastal nations of the world which should significantly affect future mineral markets and the balance of economic powers. Significant applied research efforts are ongoing for marine minerals as an adjunct to commercial production in southern Africa for diamonds; and in many other parts of the world for sands for beach and coastal protection. Forward planing, including research and development activities focussed on future commercial production of metalliferous oxides, continues in Korea, China, Japan, India, and with lesser activity, in the United States, United Kingdom, Germany and the CIS. Annual expenditures for this work amount to millions of dollars. In all cases the environmental aspects of commercial produc¬tion are a significant part of the research. Geologic studies on the occurence and distribution of metal sulfides at plate boundaries continue on a regional basis in the Pacific.

Jan 1, 1996

By Hans Smit

The face of mining as we know is changing as mining companies all over the globe realize the reality of accessing the vast mineral wealth contained on, and under, our ocean floors. With some land based mineral deposits being fully exploited across the world, deep sea mining is set to revolutionize global approaches to the search for precious metals and other sought after minerals. Previously, the financial and technological implications of deep sea mining outweighed the benefits of access to the mineral rich deposits identified all around the world. The process of marine diamond mining off the west coast of southern Africa started in the late 1950s, and subsequently continued by De Beers to the present day, has proven to be an excellent proving ground for the development of technology and mining systems that ensure a sustainable and financially viable business.

Jan 1, 2011

By S. Kim Juniper

Ocean observatory technologies permit uninterrupted, real-time observation of dynamic seafloor environments such as gas hydrate deposits and hydrothermal vent fields that are of both scientific and economic interest. Such observations enable new discoveries of linkages between physical, chemical and biological processes and could permit continuous monitoring of environmental variables during mining operations. Ocean Networks Canada operates the NEPTUNE and VENUS cabled observatories in the Northeast Pacific Ocean. The offshore NEPTUNE observatory supports instruments at two gas hydrate sites on the continental margin off Vancouver Island, and in the hydrothermal vent fields of the Endeavour segment of the Juan de Fuca Ridge. The primary focus of the gas hydrate field observations is to understand the dynamics of the growth and stability of outcropping and sub-seafloor hydrate deposits. Outcropping hydrates at 840 m depth in Barkley Canyon have been monitored for the past 3 years with a mobile instrument platform known as Wally, which is operated over the Internet by a research group in Germany. This tracked vehicle carries standard oceanographic sensors, acoustic current metres, cameras and methane sensors. Data indicate a relationship between degassing of hydrates and tidal currents. In 2012-2013 two high-resolution sonar towers were added to the hydrate field to provide precision tracking of Wally and to monitor volume changes in the outcropping hydrate mounds. A large subsurface hydrate deposit occurs at the Clayoquot Slope site, where bottom depth is 1260 metres. Monitoring instrumentation is currently being established at this location. Gas bubble release from this deposit is being monitored by a sector scanning sonar mounted on a

Sep 14, 2011

By Derek Ellis

There are two environmental issues which have only recently begun to need planning in detail for marine mining. One is the environmental consequences of mine closure; the other is environmental terrorism. In principle it is not difficult to predict the pattern and rate of biodiversity recovery after mine closure on metalliferous depositional seabeds. 1-5 years to a self-sustaining community of organisms is a generalized guideline, depending on depth and particulate composition. The rate and pattern of biodiversity recovery on some metalliferous hard-rock habitats is far less predictable due to the patchiness and rareness of the habitat. Ecoterrorism at mines, whether on-land or marine, is now to be expected. A good example of resource industry ecoterrorism is the fire-bombing of logging and cement trucks in Oregon in 2001. But there have also been bombs at mine sites, as at Asbestos, Quebec. It is also possible to regard some resource-loss lawsuits as frivolous, hence forms of ecoharassment. Marine mining operations should take note of the development of environmental terrorism (and terrorism in general) and its various manifestations and impacts. Potentially these range from minor work stoppage inconveniences, to serious financial risk jeopardizing the economics of a mine, to jail for company executives, managers and environmental staff, and to harassment and killing of mine personnel.

Jan 1, 2005