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Deep sea mining is a growing subfield of experimental
seabed mining Seabed mining, also known as Seafloor mining is the recovery of minerals from the seabed by techniques of underwater mining. The concept includes mining at shallow depths on the continental shelf and deep-sea mining at greater depths associated w ...
that involves the retrieval of minerals and deposits from the
ocean floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
found at depths of or greater. As of 2021, the majority of marine mining efforts are limited to shallow coastal waters only, where sand, tin and diamonds are more readily accessible. There are three types of deep sea mining that have generated great interest:
polymetallic nodule Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, de ...
mining, polymetallic sulphide mining, and the mining of
cobalt Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, pr ...
-rich ferromanganese crusts. The majority of proposed deep sea mining sites are near of
polymetallic nodules Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, dep ...
or active and extinct
hydrothermal vent A hydrothermal vent is a fissure on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspot ...
s at below the ocean’s surface. The vents create globular or
massive sulfide deposits Massive sulfide deposits are ore deposits that have significant stratiform ore body, ore bodies consisting mainly of sulfide minerals. Most massive sulfide ore deposits have other portions that are not massive, including stringer or feeder zones be ...
, which contain valuable metals such as
silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...
,
gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...
,
copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
,
manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
,
cobalt Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, pr ...
, and
zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
. The deposits are mined using either hydraulic pumps or bucket systems that take ore to the surface to be processed. Marine minerals include sea-dredged and seabed minerals. Sea-dredged minerals are normally extracted by dredging operations within coastal zones, to maximum sea depths of about 200 m. Minerals normally extracted from these depths include sand, silt and mud for construction purposes, mineral rich sands such as ilmenite and diamonds. As with all mining operations, deep sea mining raises questions about its
environmental impact Environmental issues are effects of human activity on the biophysical environment, most often of which are harmful effects that cause environmental degradation. Environmental protection is the practice of protecting the natural environment on t ...
. There is a growing debate about whether deep sea mining should be allowed or not. Environmental advocacy groups such as
Greenpeace Greenpeace is an independent global campaigning network, founded in Canada in 1971 by Irving Stowe and Dorothy Stowe, immigrant environmental activists from the United States. Greenpeace states its goal is to "ensure the ability of the Earth t ...
and the
Deep Sea Mining Campaign Deep or The Deep may refer to: Places United States * Deep Creek (Appomattox River tributary), Virginia * Deep Creek (Great Salt Lake), Idaho and Utah * Deep Creek (Mahantango Creek tributary), Pennsylvania * Deep Creek (Mojave River tributary), ...
have argued that seabed mining should not be permitted in most of the world's oceans because of the potential for damage to deep sea ecosystems and pollution by heavy metal-laden plumes. Prominent environmental activists and state leaders have also called for moratoriums or total bans due to the potential of devastating environmental impacts. Some argue that there should be a total ban on seabed mining. Some anti-seabed mining campaigns have won the support of large industry such as some of the technology giants, and large car companies. However, these same companies will be increasingly reliant on the metals seabed minerals can provide. Some scientists argue that seabed mining should not go ahead, as we know such a relatively small amount about the biodiversity of the deep ocean environment. Individual countries with significant deposits of seabed minerals within their large EEZ’s are making their own decisions pertaining to seabed mining, exploring ways of undertaking seabed mining without causing too much damage to the deep ocean environment, or deciding not to develop seabed mines. Some companies are attempting to build polymetallic deep sea mining equipment which does no serious harm and preservers the marine habitat. As of 2022 there was no commercial mining of seabed minerals. However, the
International Seabed Authority The International Seabed Authority (ISA) (french: Autorité internationale des fonds marins) is a Kingston, Jamaica-based intergovernmental body of 167 member states and the European Union established under the 1982 UN Convention on the Law of ...
has granted 19 exploration licenses for polymetallic nodules, within the
Clarion Clipperton Zone The Clipperton Fracture Zone, also known as the Clarion-Clipperton Zone, is a geological submarine fracture zone of the Pacific Ocean, with a length of around 4500 miles (7240 km). The zone spans approximately . It is one of the five major l ...
. The Cook Islands Seabed Minerals Authority (SBMA) has granted 3 exploration licenses for polymetallic nodules within their EEZ. There is the potential for mining at a range of scales within the oceans from small to very large. Technologies involved in the mining of seabed minerals would be highly technological, and involve a range of robotic mining machines, as well as surface ships, and metal refineries at onshore locations. One vision for the post-fossil fuel world will rely on wind farms, solar energy, electric cars, and improved battery technologies: these use a high volume and wide range of metallic commodities including ‘green’ or ‘critical’ metals many of which are in relatively short supply. Seabed mining could provide a near-term solution to the provision of many of these metals, though only serves to worsen the fundamental problems posed by extraction.SPC (2013)
Deep Sea Minerals: Deep Sea Minerals and the Green Economy
. Baker, E., and Beaudoin, Y. (Eds.) Vol. 2, Secretariat of the Pacific Community


Mining sites

Deep sea mining is a relatively new mineral retrieval process undergoing research which takes place on the
ocean floor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
. Ocean mining sites are usually around large areas of
polymetallic nodules Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, dep ...
or active and extinct
hydrothermal vent A hydrothermal vent is a fissure on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspot ...
s at about 3,000 – 6,500 meters below the ocean's surface. The vents create sulfide deposits, which contain
precious metal Precious metals are rare, naturally occurring metallic chemical elements of high economic value. Chemically, the precious metals tend to be less reactive than most elements (see noble metal). They are usually ductile and have a high lustre. ...
s such as
silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...
,
gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...
,
copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
,
manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
,
cobalt Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, pr ...
, and
zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
. The deposits are mined using either hydraulic pumps or bucket systems that take ore to the surface to be processed.


Types of minerals

Seabed minerals are mostly located between 1 and 6 km beneath the ocean surface and comprise three main types: * Polymetallic or Manganese nodules are found between 4 and 6 km beneath the sea surface, largely within abyssal plain environments. Manganese and related hydroxides precipitate from ocean water or sediment-pore water around a nucleus, which may be a shark’s tooth or a quartz grain, forming potato-shaped nodules some 4–14 cm in diameter. They accrete very slowly at rates of 1–15 mm per million years. Polymetallic/Manganese nodules are rich in many elements including rare earths, cobalt, nickel, copper, molybdenum, lithium, and Yttrium. The largest deposits of Polymetallic Nodules occur in the Pacific Ocean between Mexico and Hawaii in an area called the Clarion Clipperton Fracture Zone. The Cook Islands contains the world’s fourth largest Polymetallic Nodule deposit in an area called the South Penrhyn basin close to the
Manihiki Plateau The Manihiki Plateau is an oceanic plateau in the south-west Pacific Ocean. The Manihiki Plateau was formed by volcanic activity 125 to 120 million years ago during the mid- Cretaceous period at a triple junction plate boundary called the Tongarev ...
. * Polymetallic or seabed massive sulfide deposits that form in active oceanic tectonic settings such as island arcs and back-arcs and mid ocean ridge environments. These deposits are associated with hydrothermal activity and
hydrothermal vent A hydrothermal vent is a fissure on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspot ...
s at sea depths of mostly between 1 and 4 km. Polymetallic Sulfide minerals are rich in copper, gold, lead, silver and other metals. They are found within the Mid Atlantic Ridge system, around Papua New Guinea, Solomon Islands, Vanuatu, and Tonga and other similar ocean environments around the world. * Cobalt-rich crusts (CRC’s) form on sediment free rock surfaces, around oceanic seamounts, ocean plateau and other elevated topographic features within the ocean. The deposits are found at depths of 600–7000 m beneath sea level and form ‘carpets’ of polymetallic rich layers about 30 cm thick at the surface of the elevated features. Crusts are rich in a range of metals including cobalt, tellurium, nickel, copper, platinum, zirconium, tungsten and rare earth elements. They are found in many parts of all oceans such as seamounts in the Atlantic and Indian Oceans, as well as countries such as the Federated States of Micronesia, Marshall Islands, and Kiribati. The deep sea contains many different resources available for extraction, including silver, gold, copper, manganese, cobalt, and zinc. These raw materials are found in various forms on the sea floor. Diamonds are also mined from the seabed by De Beers and others. Cobalt-rich ferromanganese formations are found at various depths between 400 and 7000 meters below sea level (masl). These formations are a type of Manganese crust deposits. The substrates of rock consist of layered iron and Magnesium layers ( Fe-Mn oxyhydroxide deposits ) that will host mineralization. Cobalt-rich ferromanganese formations exist in two categories depending on the
Depositional environment In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will be ...
, (1) hydrogenetic cobalt-rich ferromanganese crusts and (2) hydrothermal crusts and encrustations. Temperature, depth and sources of seawater are dependent variables that shape how the formations grow. Hydrothermal crusts precipitate quickly, near 1600–1800 mm/Ma and grow in hydrothermal fluids at approximately 200 °C. Hydrogenetic crusts grow much slower at 1–5 mm/Ma but will have higher concentrations of critical metals. Submarine seamount provinces, linked to hotspots and seafloor spreading, vary in depth along the ocean floor. These seamount show characteristics distribution that connects them to Cobalt-rich ferromanganese formation. In Western Pacific, a study conducted at <1500 m to 3500 m (mbsl) proved that the cobalt crusts are concentrated in the seamount section that slops at less than 20°. The high-grade cobalt crust in the Western Pacific trended /correlated with latitude and longitude, a high region within 150°E‐140°W and 30°S‐30°N Polymetallic sulphides are resources available for extraction from
Seafloor massive sulfide deposits Seafloor massive sulfide deposits or SMS deposits, are modern equivalents of ancient volcanogenic massive sulfide ore deposits or VMS deposits. The term has been coined by mineral explorers to differentiate the modern deposit from the ancient. SM ...
, composed on and within the seafloor base when mineralized water discharges from
Hydrothermal vent A hydrothermal vent is a fissure on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspot ...
. The hot mineral-rich water precipitates and condenses when released from hydrothermal vents and meets the cold seawater. The stock area of the chimney structures of hydrothermal vents can be highly mineralized. Polymetallic nodules/manganese nodules are founded on
Abyssal plain An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between and . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface. T ...
, in a range of sizes, some as large as 15 cm long. The Clipperton Fracture Zone (CCZ) is a well known area of occurrences. Nodules are recorded to have average growth rates near 10–20 mm/Ma. The Clipperton Fracture Zone is host to the largest untapped deposit nickel resource; Polymetallic nodules or
Manganese nodule Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, de ...
sit on the seafloor. These nodules require no need for drilling or typical Surface mining techniques. The composition of nickel, cobalt, copper and manganese make up nearly 100% of the nodules, and generates no toxic tailings. Polymetallic nodules in the Clipperton Fracture Zone are currently being studied to produce battery metals.


Deep sea mining efforts

Over the past decade, a new phase of deep-sea mining has begun. Rising demand for precious metals in
Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
,
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
,
Korea Korea ( ko, 한국, or , ) is a peninsular region in East Asia. Since 1945, it has been divided at or near the 38th parallel, with North Korea (Democratic People's Republic of Korea) comprising its northern half and South Korea (Republic o ...
and
India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
has pushed these countries in search of new sources. Interest has recently shifted toward
hydrothermal vent A hydrothermal vent is a fissure on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hotspot ...
s as the source of metals instead of scattered nodules. The trend of transition towards an electricity-based information and transportation infrastructure currently seen in western societies further pushes demands for precious metals. The current revived interest in phosphorus nodule mining at the seafloor stems from phosphor-based artificial fertilizers being of significant importance for world food production. Growing world population pushes the need for artificial fertilizers or greater incorporation of organic systems within agricultural infrastructure. The world's first "large-scale" mining of hydrothermal vent mineral deposits was carried out by Japan in August - September, 2017.
Japan Oil, Gas and Metals National Corporation The , is a Japanese government Independent Administrative Institution which was created in 2004 when the former Japan National Oil Corporation merged with the former Metal Mining Agency of Japan. See also * Critical mineral raw materials * Ene ...
(JOGMEC) carried out this operation using the Research Vessel Hakurei. This mining was carried out at the 'Izena hole/cauldron' vent field within the hydrothermally active back-arc basin known as the
Okinawa Trough The (also called , literally China-Ryukyu Border Trough ) is a seabed feature of the East China Sea. It is an active, initial back-arc rifting basin which has formed behind the Ryukyu arc-trench system in the West Pacific. It developed where th ...
which contains 15 confirmed vent fields according to th
InterRidge Vents Database
A deep sea mining venture in
Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...
, the Solwara 1 Project, was granted a mining permit to begin mining a high grade copper-gold resource from a weakly active hydrothermal vent. This controversial project generated an enormous backlash from the community and environmental activists The Solwara 1 Project was located at 1600 metres water depth in the
Bismarck Sea The Bismarck Sea (, ) lies in the southwestern Pacific Ocean within the nation of Papua New Guinea. It is located northeast of the island of New Guinea and south of the Bismarck Archipelago. It has coastlines in districts of the Islands Regi ...
,
New Ireland Province New Ireland Province, formerly New Mecklenburg (german: Neu-Mecklenburg), and Nova Hibernia, is the northeasternmost province of Papua New Guinea. Physical geography The largest island of the province is New Ireland. Also part of the province a ...
. Using ROV (
remotely operated underwater vehicle A remotely operated underwater vehicle (technically ROUV or just ROV) is a tethered underwater mobile device, commonly called ''underwater robot''. Definition This meaning is different from remote control vehicles operating on land or in the ai ...
s) technology developed by UK-based Soil Machine Dynamics, Nautilus Minerals Inc. was the first company of its kind to announce plans to begin full-scale undersea excavation of mineral deposits."Treasure on the ocean floor"
. ''Economist'' 381, no. 8506: 10. (30 November 2006)
However a dispute with the government of Papua-New Guinea delayed production and operations until early 2018. In September 2019, it was announced that the project had collapsed as Nautilus Minerals Inc. went into administration and its major creditors sought to recoup the millions of dollars they had sunk into the project. The Prime Minister of Papua New Guinea called the project a "total failure", sparking calls for a deep sea mining moratorium from his Pacific counterparts. An additional site that is being explored and looked at as a potential deep sea mining site is the
Clarion-Clipperton Fracture Zone The Clipperton Fracture Zone, also known as the Clarion-Clipperton Zone, is a geological submarine fracture zone of the Pacific Ocean, with a length of around 4500 miles (7240 km). The zone spans approximately . It is one of the five major l ...
(CCZ). The CCZ stretches over 4.5 million square kilometers of the Northern Pacific Ocean between Hawaii and Mexico. Scattered across the
abyssal plain An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between and . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface. T ...
are trillions of
polymetallic nodules Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, dep ...
, potato-sized rocklike deposits containing minerals such as magnesium, nickel, copper, zinc, cobalt, and others. Development of technologies to collect polymetallic nodules in the CCZ began in the 1970s when oil, gas and mining majors including Shell, Rio Tinto (Kennecott) and Sumitomo, conducted pilot test work, recovering over ten thousand tons of nodules. Polymetallic nodules are also abundant in the Central Indian Ocean Basin and the Peru Basin. Mining claims registered with the
International Seabed Authority The International Seabed Authority (ISA) (french: Autorité internationale des fonds marins) is a Kingston, Jamaica-based intergovernmental body of 167 member states and the European Union established under the 1982 UN Convention on the Law of ...
(ISA) are mostly located in the CCZ, most commonly in the manganese nodule province. The ISA has entered into 18 different contracts with private companies and national governments to explore the suitability of polymetallic nodule mining in the CCZ. In 2019, the government of the
Cook Islands ) , image_map = Cook Islands on the globe (small islands magnified) (Polynesia centered).svg , capital = Avarua , coordinates = , largest_city = Avarua , official_languages = , lan ...
passed two legislative bills pertaining to deep sea mining in the country's EEZ. The ''Sea Bed Minerals (SBM)'' ''Act of 2019'' was passed to "enable the effective and responsible management of the seabed minerals of the Cook Islands in a way that also...seeks to maximize the benefits of seabed minerals for present and future generations of Cook Islanders." Sea Bed Minerals (Exploration) Regulations Act and the Sea Bed Minerals Amendment Act were passed by Parliament in 2020 and 2021 respectively. As much as 12 billion tons of polymetallic nodules are spread across the ocean floor in the Cook Island's EEZ. The nodules found in the EEZ contain cobalt, nickel, manganese, titanium, and
Rare Earth Elements The rare-earth elements (REE), also called the rare-earth metals or (in context) rare-earth oxides or sometimes the lanthanides (yttrium and scandium are usually included as rare earths), are a set of 17 nearly-indistinguishable lustrous silve ...
. On November 10, 2020, the Chinese submersible Fendouzhe reached the bottom of the
Mariana Trench The Mariana Trench is an oceanic trench located in the western Pacific Ocean, about east of the Mariana Islands; it is the deepest oceanic trench on Earth. It is crescent-shaped and measures about in length and in width. The maximum know ...
10,909 meters (35,790 feet). It didn't surpass the record of American undersea explorer
Victor Vescovo Victor Lance Vescovo (born 1966) is an American private equity investor, retired naval officer, space tourist and undersea explorer. He is a co-founder and managing partner of private equity company Insight Equity Holdings. Vescovo achieved the ...
who claimed 10,927 meters (35,853 feet) in May 2019. Chief designer of the submersible, Ye Cong said the seabed was abundant with resources and a "treasure map" can be made of the deep sea.


Extraction methods

Each of the different deep sea mining resource will involve different technology. New robotics and AI solutions are in development to minimize the environment damage and improve the economics.
Recent technological advancements This is a list of emerging technologies, in-development technical innovations with significant potential in their applications. The criteria for this list is that the technology must: # Exist in some way; purely hypothetical technologies can ...
have given rise to the use remotely operated vehicles (ROVs) to collect mineral samples from prospective mine sites. Using drills and other cutting tools, the ROVs obtain samples to be analyzed for precious materials. Once a site has been located, a mining ship or station is set up to mine the area. There are two predominant forms of mineral extraction being considered for full-scale operations: continuous-line bucket system (CLB) and the hydraulic suction system. The CLB system is the preferred method of nodule collection. It operates much like a conveyor-belt, running from the sea floor to the surface of the ocean where a ship or mining platform extracts the desired minerals, and returns the
tailings In mining, tailings are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are different to overburden, which is the waste rock or other material that overlie ...
to the ocean. Hydraulic suction mining lowers a pipe to the seafloor which transfers nodules up to the mining ship. Another pipe from the ship to the seafloor returns the tailings to the area of the mining site. In recent years, the most promising mining areas have been the Central and Eastern Manus Basin around Papua New Guinea and the crater of Conical Seamount to the east. These locations have shown promising amounts of gold in the area's sulfide deposits (an average of 26
parts per million In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they ...
). The relatively shallow water depth of 1050 m, along with the close proximity of a gold processing plant makes for an excellent mining site. Deep sea mining project value chain can be differentiated using the criteria of the type of activities where the value is actually added. During prospecting, exploration and resource assessment phases the value is added to intangible assets, for the extraction, processing and distribution phases the value increases with relation to product processing. There is an intermediate phase – the pilot mining test which could be considered to be an inevitable step in the shift from “resources” to “reserves” classification, where the actual value starts.Abramowski, T. (2016)
Value chain of deep seabed mining
, Article in the book: Deep sea mining value chain: organization, technology and development, pp 9-18, Interoceanmetal Joint Organization
Exploration phase involves such operations as locating, sea bottom scanning and sampling using technologies such as echo-sounders, side scan sonars, deep-towed photography, ROVs, AUVs. The resource valuation incorporates the examination of data in the context of potential mining feasibility. Value chain based on product processing involves such operations as actual mining (or extraction), vertical transport, storing, offloading, transport, metallurgical processing for final products. Unlike the exploration phase, the value increases after each operation on processed material eventually delivered to the metal market. Logistics involves technologies analogous to those applied in land mines. This is also the case for the metallurgical processing, although rich and polymetallic mineral composition which distinguishes marine minerals from its land analogs requires special treatment of the deposit. Environmental monitoring and impact assessment analysis relate to the temporal and spatial discharges of the mining system if they occur, sediment plumes, disturbance to the benthic environment and the analysis of the regions affected by seafloor machines. The step involves an examination of disturbances near the seafloor, as well as disturbances near the surface. Observations include baseline comparisons for the sake of quantitative impact assessments for ensuring the sustainability of the mining process. Small scale mining of the deep sea floor is being developed off the coast of
Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...
using
robot A robot is a machine—especially one programmable by a computer—capable of carrying out a complex series of actions automatically. A robot can be guided by an external control device, or the control may be embedded within. Robots may be c ...
ic techniques, but the obstacles are formidable.


Environmental impacts

As with all mining operations, deep sea mining raises questions about potential environmental damages to the surrounding areas. Because deep sea mining is a relatively new field, the complete consequences of full-scale mining operations are under investigation. Newer technology which is being developed has the potential to avoid sediment plumes and use selective pick up technology. Selective pickup avoids picking up any nodules which contain life and can be programmed to leave behind a percentage of the nodules to maintain the habitat. This is not possible with dredging collector machines. However, experts are certain that removal of parts of the sea floor will result in disturbances to the benthic layer, increased
toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...
of the
water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...
, and sediment plumes from tailings. Removing parts of the sea floor disturbs the habitat of benthic organisms, possibly, depending on the type of mining and location, causing permanent disturbances. Aside from direct impact of mining the area, leakage, spills, and
corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...
could alter the mining area's chemical makeup. Among the impacts of deep sea mining, it is theorized that sediment plumes could have the greatest impact. Plumes are caused when the tailings from mining (usually fine particles) are dumped back into the ocean, creating a cloud of particles floating in the water. Two types of plumes occur: near-bottom plumes and surface plumes. Near-bottom plumes occur when the tailings are pumped back down to the mining site. The floating particles increase the
turbidity Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids can ...
, or cloudiness, of the water, clogging
filter-feeding Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...
apparatuses used by benthic organisms. Surface plumes cause a more serious problem. Depending on the size of the particles and water currents the plumes could spread over vast areas. The plumes could impact
zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
and light penetration, in turn affecting the
food web A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. Another name for food web is consumer-resource system. Ecologists can broadly lump all life forms into one ...
of the area. Further research has been conducted by the
Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
to investigate how these plumes travel through water and how their ecological impact could be mitigated. This research is used to contribute to the work of the
International Seabed Authority The International Seabed Authority (ISA) (french: Autorité internationale des fonds marins) is a Kingston, Jamaica-based intergovernmental body of 167 member states and the European Union established under the 1982 UN Convention on the Law of ...
, the body which is mandated to develop, implement and enforce rules for deep-sea mining activities within its area of responsibility, in gaining a full understanding of the environmental impacts. Many opponents to deep sea mining efforts point to the threats of grave and irreversible damage it could cause to fragile deep sea ecosystems. For this reason, organizations
Fauna and Flora International Fauna & Flora International (FFI) is an international conservation charity and non-governmental organization dedicated to protecting the planet's threatened wildlife and habitats. Founded in 1903, it is the world's oldest international conserva ...
and
World Wide Fund for Nature The World Wide Fund for Nature Inc. (WWF) is an international non-governmental organization founded in 1961 that works in the field of wilderness preservation and the reduction of human impact on the environment. It was formerly named the Wor ...
, broadcaster
David Attenborough Sir David Frederick Attenborough (; born 8 May 1926) is an English broadcaster, biologist, natural historian and author. He is best known for writing and presenting, in conjunction with the BBC Natural History Unit, the nine natural histor ...
, and companies BMW,
Google Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...
,
Volvo Cars Volvo Cars ( sv, Volvo personvagnar, styled VOLVO in the company's logo) is a Swedish multinational manufacturer of luxury vehicles headquartered in Torslanda, Gothenburg. The company manufactures SUVs, station wagons, and sedans. The company's ...
and
Samsung The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...
have called for a global moratorium on deep sea mining.


Marine life

Research shows that polymetallic nodule fields are hotspots of abundance and diversity for a highly vulnerable abyssal fauna. Because deep sea mining is a relatively new field, the complete consequences of full-scale mining operations on this ecosystem are unknown. However, some researchers have said they believe that removal of parts of the sea floor will result in disturbances to the benthic layer, increased
toxicity Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...
of the
water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...
and sediment plumes from
tailings In mining, tailings are the materials left over after the process of separating the valuable fraction from the uneconomic fraction (gangue) of an ore. Tailings are different to overburden, which is the waste rock or other material that overlie ...
. Removing parts of the sea floor could disturb the habitat of benthic organisms, with unknown long-term effects. Preliminary studies on seabed disturbances from mining-related activities have indicated that it takes decades for the seabed to recover from minor disturbances. Minerals targeted by seabed mining activities take millions of years to regenerate, if they do so at all. Aside from the direct impact of mining the area, some researchers and environmental activists have raised concerns about leakage, spills and
corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...
that could alter the mining area’s chemical makeup.
Polymetallic Nodule Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, de ...
fields form some of the few areas of hard substrate on the
pelagic red clay Pelagic red clay, also known as simply red clay, brown clay or pelagic clay, is a type of pelagic sediment.Rothwell, R.G., (2005) ''Deep Ocean Pelagic Oozes'', Vol. 5. of Selley, Richard C., L. Robin McCocks, and Ian R. Plimer, Encyclopedia of Ge ...
bottom, attracting macrofauna. In 2013, Researchers from the University of Hawaii at Manoa conducted a baseline study of benthic communities in the CCZ, assessing a 350 square mile area with a remote-operated vehicle (ROV). They found that the area surveyed contained one of the most diverse megafaunal communities recorded on the
abyssal plain An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between and . Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth's surface. T ...
. The megafauna (species greater than 0.78 inches) surveyed included glass sponges, anemones, eyeless fish, sea stars, psychropotes, amphipods, and isopods. Macrofauna (species greater than 0.5mm) were found to have very high local species diversity, with 80 -100 macrofaunal species per square meter. The highest species diversity was found living amongst the polymetallic nodules. In a follow-up survey, researchers identified over 1000 species, 90% of them previously unknown, and over 50% of them dependent on the polymetallic nodules for survival; all were identified in areas demarcated for potential seabed mining. Many scientists believe that seabed mining is posed to irreparably harm fragile abyssal plain habitats. Despite the potential environmental impacts, research shows that the loss of biomass involved in Deep Sea Mining is significantly smaller than the expected loss of biomass as a result of land ore mining. It is estimated that with the continued process of land ore mining will lead to a loss of 568 megatons (approximately the same as that of the entire human population) of
biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...
whereas projections of the potential environmental impact of Deep Sea Mining will lead to a loss of 42 megatons of biomass. In addition to the loss of biomass, land ore mining will lead to a loss of 47 trillion megafauna organisms, whereas deep-sea mining is expected to lead to a loss of 3 trillion
megafauna In terrestrial zoology, the megafauna (from Greek μέγας ''megas'' "large" and New Latin ''fauna'' "animal life") comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common threshold ...
organisms In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi; ...
. A rare species called '
Scaly-foot snail ''Chrysomallon squamiferum'', commonly known as the scaly-foot gastropod, scaly-foot snail, sea pangolin, or volcano snail is a species of deep-sea hydrothermal-vent snail, a marine gastropod mollusc in the family Peltospiridae. This vent-end ...
', also known as sea pangolin, has become first species to be threatened because of deep sea mining.


Sediment Plumes

Among the impacts of deep sea mining, sediment plumes could have the greatest impact. Plumes are caused when the tailings from mining (usually fine particles) are dumped back into the ocean, creating a cloud of particles floating in the water. Two types of plumes occur: near bottom plumes and surface plumes. Near bottom plumes occur when the tailings are pumped back down to the mining site. The floating particles increase the
turbidity Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids can ...
, or cloudiness, of the water, clogging
filter-feeding Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...
apparatuses used by benthic organisms. Surface plumes cause a more serious problem. Depending on the size of the particles and water currents the plumes could spread over vast areas. The plumes could impact
zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...
and light penetration, in turn affecting the
food web A food web is the natural interconnection of food chains and a graphical representation of what-eats-what in an ecological community. Another name for food web is consumer-resource system. Ecologists can broadly lump all life forms into one ...
of the area. A study conducted in Portmán Bay (Murcia, Spain) revealed that sediment plumes carry concentrations of metals that can accumulate in tissues of shellfish and persist for several hours after initial mining activities. Mine tailing deposits and resuspension plume sites caused the worst environmental conditions of their area compared to sites just off the mine tailing deposits, leaving significant ecotoxicological impacts on fauna within a short period of time. The accumulation of toxic metals in an organism, known as
bioaccumulation Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...
, works its way through the food web causing detrimental health effects in larger organisms and essentially humans.


Noise and Light Pollution

Deep Sea Mining efforts will increase ambient noise in the normally-quiet pelagic environments. Anthropogenic noise is known to affect deep sea fish species and marine mammals. Impacts include behavior changes, communication difficulties, and temporary and permanent hearing damage. The areas where Deep Sea Mining may take places are normally devoid of sunlight and anthropogenic light sources. Mining efforts employ floodlighting would drastically increase light levels. Previous studies show that deep sea shrimps found at hydrothermal vents suffered permanent retinal damage when exposed to floodlights from crewed submersibles. Behavioral changes include vertical migration patterns, ability to communicate, and detect prey. Each source of pollution contribute to alterations of ecosystems beyond points of immediate recovery.


Laws and regulations

The international law–based regulations on deep sea mining are contained in the United Nations Conventions on the Law of the Sea from 1973 to 1982, which came into force in 1994. The convention set up the
International Seabed Authority The International Seabed Authority (ISA) (french: Autorité internationale des fonds marins) is a Kingston, Jamaica-based intergovernmental body of 167 member states and the European Union established under the 1982 UN Convention on the Law of ...
(ISA), which regulates nations’ deep sea mining ventures outside each nations’ Exclusive Economic Zone (a area surrounding coastal nations). The ISA requires nations interested in mining to explore two equal mining sites and turn one over to the ISA, along with a transfer of mining technology over a 10- to 20-year period. This seemed reasonable at the time because it was widely believed that nodule mining would be extremely profitable. However, these strict requirements led some industrialized countries to refuse to sign the initial treaty in 1982. The United States abides by the Deep Seabed Hard Mineral Resources Act, which was originally written in 1980. This legislation is largely recognized as one of the main concerns the US has with ratifying UNCLOS. Deep sea mining efforts within the EEZ of nation states seabed mining comes under the jurisdiction of national laws. Despite extensive exploration both within and outside of EEZs, only a few countries, notably New Zealand, have established legal and institutional frameworks for the future development of deep seabed mining. Papua New Guinea was the first country to approve a permit for the exploration of minerals in the deep seabed. Solwara 1 was awarded its licence and environmental permits despite three independent reviews of the environmental impact statement mine finding significant gaps and flaws in the underlying science. The ISA has recently arranged a workshop in Australia where scientific experts, industry representatives, legal specialists and academics worked towards improving existing regulations and ensuring that development of seabed minerals does not cause serious and permanent damage to the marine environment. A moratorium on deep sea mining was adopted at the Global biodiversity summit in 2021. Some argue that deep sea mining is needed for producing
Electric vehicle An electric vehicle (EV) is a vehicle that uses one or more electric motors for propulsion. It can be powered by a collector system, with electricity from extravehicular sources, or it can be powered autonomously by a battery (sometimes cha ...
s and batteries, but according to Jessica Battle, an expert on ocean policy and governance: "We can decarbonize through innovation, redesigning, reducing, reusing, and recycling."


Controversy

An article in the Harvard Environmental Law Review in April 2018 argued that "the 'new global gold rush' of deep sea mining shares many features with past resource scrambles – including a general disregard for environmental and social impacts, and the marginalisation of indigenous peoples and their rights". The Foreshore and Seabed Act (2004) ignited fierce indigenous opposition in New Zealand, as its claiming of the seabed for the Crown in order to open it up to mining conflicted with Māori claims to their customary lands, who protested the Act as a "sea grab". Later, this act was repealed after an investigation from the UN Commission on Human Rights upheld charges of discrimination. The Act was subsequently repealed and replaced with the Marine and Coastal Area Bill (2011). However, conflicts between indigenous sovereignty and seabed mining continue. Organizations like the Deep Sea Mining Campaign and Alliance of Solwara Warriors, comprising 20 communities in the Bismarck and Solomon Sea, are examples of organizations that are seeking to ban seabed mining in
Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...
, where the Solwara 1 project is set to occur, and in the Pacific. They argue primarily that decision-making about deep sea mining has not adequately addressed Free Prior and Informed Consent from affected communities and have not adhered to the
precautionary principle The precautionary principle (or precautionary approach) is a broad epistemological, philosophical and legal approach to innovations with potential for causing harm when extensive scientific knowledge on the matter is lacking. It emphasizes caut ...
, a rule proposed by the 1982 UN World Charter for Nature which informs the ISA regulatory framework for mineral exploitation of the deep sea.


History

In the 1960s, the prospect of deep-sea mining was brought up by the publication of J. L. Mero's ''Mineral Resources of the Sea''. The book claimed that nearly limitless supplies of cobalt,
nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...
and other metals could be found throughout the planet's oceans. Mero stated that these metals occurred in deposits of
manganese nodules Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core. As nodules can be found in vast quantities, and contain valuable metals, de ...
, which appear as lumps of compressed flowers on the seafloor at depths of about 5,000 m. Some nations including
France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
,
Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
and the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
sent out research vessels in search of nodule deposits. Initial estimates of deep sea mining viability turned out to be much exaggerated. This overestimate, coupled with depressed metal prices, led to the near abandonment of nodule mining by 1982. From the 1960s to 1984 an estimated US $650 million had been spent on the venture, with little to no return.


Deep sea mining equipment


See also

* * * * , the process of creating holes for oil mining in deep sea. *, concretions of manganese and other minerals formed over thousands of years on the abyssal plains; sought after for deep sea mining projects. *, location of interest for deep sea mining * * *


References


External links


The Deep Sea Mining Summit 2023
"The international forum for deep sea mining professionals"

in ''
Multinational Monitor The ''Multinational Monitor'' was a bimonthly magazine founded by Ralph Nader in 1980. It was published by Essential Information. The magazine was formerly published on a monthly basis. Although its primary focus was on analysis of corporations, ...
'' * ttp://www.abc.net.au/catalyst/stories/3240156.htm Deep Sea Mining– 8 min video on Australian science TV, June 2011
Geophysical Methods for the Mapping of Deep-Sea Mineral Deposits
– November 2014 Ocean News & Technology magazine *The deep sea mining campaign - http://www.deepseaminingoutofourdepth.org/
"Why are countries laying claim to the deep-sea floor?"
- BBC article 21 June 2017
Assessment of the Different technologies for Vertical Hydraulic Transport in Deep Seam Mining ApplicationsMining the Deep Sea
{{Authority control Underwater mining Mining Oceans