Deep sea mining

Deep sea mining is the extraction of minerals from the ocean floor at depths of 200 m to 6500 m.

Deep-sea mining uses hydraulic pumps or bucket systems that carry deposits to the surface for processing.

The environmental impact of deep sea mining is controversial. Environmental advocacy groups such as Greenpeace and the Deep Sea Mining Campaign claimed that seabed mining has the potential to damage deep sea ecosystems and spread pollution from heavy metal-laden plumes. Critics have called for moratoria or permanent bans. Opposition campaigns enlisted the support of some industry figures, including firms reliant on the target metals. Individual countries with significant deposits within their exclusive economic zones (EEZ's) are exploring the subject.

As of 2022, no commercial deep sea mining was underway. However, the International Seabed Authority granted 19 exploration licenses for polymetallic nodules within the Clarion Clipperton Zone. China has exclusive rights to mine 92000 sqmi or 17 percent of the area. Mining is set to begin in 2025. In 2022 the Cook Islands Seabed Minerals Authority (SBMA) granted three exploration licenses for polymetallic nodules within their EEZ. Papua New Guinea was the first country to approve a DSM permit, to Solwara 1, even though three independent reviews of the environmental impact statement mine alleged significant gaps and flaws in the underlying science.

Related technologies include robotic mining machines, as surface ships, and offshore and onshore metal refineries.

Wind farms, solar energy, electric cars, and battery technologies use many of the deep-sea metals.

As of 2021, the majority of marine mining used dredging operations at depths of about 200 m, where sand, silt and mud for construction purposes is abundant, along with mineral rich sands containing ilmenite and diamonds.

Sites
Deep sea mining sites hold polymetallic nodules or surround active or extinct hydrothermal vents at about 3000-6500 m depth. The vents create sulfide deposits, which collect metals such as silver, gold, copper, manganese, cobalt, and zinc. The deposits are mined using hydraulic pumps or bucket systems.

The largest deposits occur in the Pacific Ocean between Mexico and Hawaii in the Clarion Clipperton Fracture Zone. It stretches over 4.5 million square kilometers of the Northern Pacific Ocean between Hawaii and Mexico. Scattered across the abyssal plain are trillions of polymetallic nodules, potato-sized rocklike deposits containing minerals such as magnesium, nickel, copper, zinc, and cobalt.

The Cook Islands contains the world's fourth largest deposit in the South Penrhyn basin close to the Manihiki Plateau.

Polymetallic nodules are found within the Mid Atlantic Ridge system, around Papua New Guinea, Solomon Islands, Vanuatu, and Tonga, and the Peru Basin.

Cobalt-rich crusts are found on seamounts in the Atlantic and Indian Oceans, as well as countries such as the Pacific Federated States of Micronesia, Marshall Islands, and Kiribati.

On November 10, 2020, the Chinese submersible Fendouzhe (Striver) reached the bottom of the Mariana Trench 10,909 meters (35,790 feet). Chief designer Ye Cong said the seabed was abundant with resources and a "treasure map" can be made.

Promising sulfide deposits (an average of 26 parts per million) were found in the Central and Eastern Manus Basin around PNG and the crater of Conical Seamount to the east. It offers relatively shallow water depth of 1050 m, along with a nearby gold refinery.

United States
A 2023 study identified four regions in US territorial waters where DSM would be possible: the Hawaiian Islands, the southeastern Blake Plateau, California, and the Gulf of Alaska. Hawaii has both nodules and CRCs, while the other sites hold CRCs. Each area features distinct risks. Mining Hawaii could generate plumes that could damage important fisheries and other marine life. California's waters host massive ship traffic and communication cables. Alaska waters are rich in bottom-dwelling commercially valuable sea life.

Deposit types
Seabed minerals include three main types: Polymetallic nodules, Polymetallic sulfide deposits, and Cobalt-rich crusts.

Polymetallic nodules
Polymetallic or manganese nodules are found at depths of 4-6 km, largely on abyssal plains. 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 at rates of 1–15 mm per million years. These nodules are rich in metals including rare earth elements, cobalt, nickel, copper, molybdenum, and yttrium.

Polymetallic nodules/manganese nodules are found on abyssal plains, in a range of sizes, some as large as 15 cm long. Nodules are reported to have average growth rates near 10–20 mm/Ma.

Polymetallic sulfides
Polymetallic or sulfide deposits 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 vents at sea depths mostly between 1 and 4 km. These minerals are rich in copper, gold, lead, silver and others.

Polymetallic sulphides appear on seafloor massive sulfide deposits. They appear on and within the seafloor when mineralized water discharges from a hydrothermal vent. The hot, mineral-rich water precipitates and condenses when it meets cold seawater. The stock area of the chimney structures of hydrothermal vents can be highly mineralized. The Clipperton Fracture Zone hosts the world's largest deposit nickel resource. These nodules sit on the seafloor and require no drilling or excavation. Nickel, cobalt, copper and manganese make up nearly 100% of the contents.

Cobalt-rich crusts
Cobalt-rich crusts (CRCs) form on sediment-free rock surfaces around oceanic seamounts, ocean plateaus, and other elevated features. The deposits are found at depths of 600-7000 m and form 'carpets' of polymetallic rich layers about 30 cm thick at the feature surface. Crusts are rich in a range of metals including cobalt, tellurium, nickel, copper, platinum, zirconium, tungsten, and rare earth elements. Temperature, depth and seawater sources shape how the formations grow.

Cobalt-rich formations exist in two categories depending on the depositional environment:
 * hydrogenetic cobalt-rich ferromanganese crusts grow at 1–5 mm/Ma, but offer higher concentrations of critical metals.
 * hydrothermal crusts and encrustations precipitate quickly, near 1600–1800 mm/Ma and grow in hydrothermal fluids at approximately 200 C

Submarine seamount provinces are linked to hotspots and seafloor spreading and vary in depth. They show characteristic distributions. In the Western Pacific, a study conducted at <1500 m to 3500 m bsl reported that cobalt crusts concentrate on less than 20° slopes. The high-grade cobalt crust in the Western Pacific correlated with latitude and longitude, a region within 150°E‐140°W and 30°S‐30°N Diamonds are mined from the seabed by De Beers and others.

Hakurei
The world's first large-scale mining of hydrothermal vent mineral deposits was carried out by Japan Oil, Gas and Metals National Corporation (JOGMEC) from August to September 2017, using the research vessel Hakurei, at the 'Izena hole/cauldron' vent field within the hydrothermally active back-arc Okinawa Trough, which contains 15 confirmed vent fields according to the InterRidge Vents Database.

Solwara 1
The Solwara 1 Project was the first time a legitimate legal contract and framework had been developed on deep sea mining. The project was based off the coast of Papua New Guinea (PNG), near New Ireland province. The project was a joint venture between Papua New Guinea and Nautilus Minerals Inc. Nautilus Minerals held a 70% stake and Papua New Guinea purchased a 30% stake in 2011. PNG's economy relies upon the mining industry, which produces around 30–35% of GDP. Nautilus Minerals is a Canadian deep-sea mining company. The project was approved in January 2011, by PNG's Minister for Mining, John Pundari. The company leased a portion of the seabed in the Bismarck Sea. The lease licensed access to 59 square kilometers. Nautilus was allowed to mine to a depth of 1,600 meters for a period of 20 years. The company then began the process of gathering the materials and raising money for the project. The intent was to mine a high grade copper-gold resource from a weakly active hydrothermal vent. The target was 1.3 tons of materials, consisting of 80,000 tons of high-grade copper and 150,000 to 200,000 ounces of gold sulfide ore, over 3 years. The project was to operate at 1600 mbsl using remotely operated underwater vehicles (ROV) technology developed by UK-based Soil Machine Dynamics.

Community and environmental activists launched the Deep Sea Mining Campaign and Alliance of Solwara Warriors, comprising 20 communities in the Bismarck and Solomon Seas who attempted to ban seabed mining. Their campaign against the Solwara 1 project lasted for 9 years. Their efforts led the Australian government to ban seabed mining in the Northern Territory. In June 2019, the Alliance of Solwara Warriors wrote the PNG government calling for them to cancel all deep sea mining licenses and ban seabed mining in national waters. They claimed that PNG had no need for seabed mining due to its abundant fisheries, productive agricultural lands, and marine life. They claimed that seabed mining benefited only a small number of already wealthy people, but not local communities and Indigenous populations. Others chose to engage in more artistic forms, such as Joy Enomoto. She created a series of woodcut prints titled Nautilus the Protector. The activist community argued that authorities had not adequately addressed free, prior and informed consent for affected communities and violated the precautionary principle.

In December 2017 the company had difficulties in raising money and eventually could no longer pay what it owed to the Chinese shipyard where the "production support vessel" was docked. Nautilus lost access to the ship and equipment. In August 2019, the company filed for bankruptcy, delisted from the Toronto Stock Exchange, and was liquidated. PNG lost over $120 million dollars. Nautilus was purchased by Deep Sea Mining Finance LTD. PNG has yet to cancel the extraction license contract.

Shell
In the 1970s Shell, Rio Tinto (Kennecott) and Sumitomo conducted pilot test work, recovering over ten thousand tons of nodules in the CCZ.

Licenses
Licences for mineral exploration in the area beyond national jurisdiction registered with the International Seabed Authority (ISA) are mostly located in the CCZ. As of May 2024 the ISA has entered into 17 contracts with private companies and national governments in the CCZ, one contract with the Government of India in the Central Indian Ocean Basin (CIOB), and one contract with Chinese contractor Beijing Pioneer Hi-Tech Development Corporation in the Prime Crust Zone (PCZ) in the Western Pacific.

Cook Islands
In 2019, the Cook Islands passed two deep sea mining laws. The Sea Bed Minerals (SBM) Act of 2019 was 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." The Sea Bed Minerals (Exploration) Regulations Act and the Sea Bed Minerals Amendment Act were enacted in 2020 and 2021, respectively.

In February 2022, the Cook Islands government Seabed Minerals Agency (SBMA) announced the award of three five-year licences exploration activities in Cook Islands EEZ to private companies Moana Minerals Limited, the Cook Islands Consortium (CIC), and Cook Islands Investment Corporation - Seabed Resources (CIIC-SR).

Moana Minerals is a subsidiary of Ocean Minerals LLC (OML), a US-based private investment firm led by President and CEO Hans Smit. Hans Smit previously led Neptune Minerals, Inc a DSM company interested in SMS exploitation in Papua New-Guinean waters. He also served as Managing Director of Royal IHC MMP, focused on underwater mining activities, and worked on underwater mining systems used for subsea diamond mining.

In 2023, the SBMA announced the results of a technical report on the polymetallic nodule deposit of the Cook Islands' exclusive economic zone, undertaken on its behalf by RSC Mining and Mineral Exploration. The study was based on the analysis of both historical samples from previous scientific cruises, as well as data from recent work undertaken by SBMA PMN exploration contractors CIIC-SR and Moana. RSC produced a JORC Code (2012)-compliant Mineral Resource Statement for parts of the EEZ totalling 6.7 billion tons of polymetallic nodules (wet), grading 0.44% Co, 0.21% Cu, 17.4% Fe, 15.8% Mn, and 0.37% Ni Of this total resource, 304 million tons of nodules grading 0.5% Co, 0.15% Cu, 18.5% Fe, 15.4% Mn, and 0.25% Ni, are assessed at Indicated Resource, whereas Inferred Resources account for 6.4 billion tons grading 0.4% Co, 0.2% Cu, 17% Fe, 16% Mn, and 0.4% Ni.

The Metals Company (TMC)
In 2023, a Canadian company, The Metals Company, partnered with the island nation of Nauru to start mining in the CCZ through its Nauru-domiciled Nauru Ocean Resources Inc. (NORI) subsidiary. It controls two further ISA exploration licences in the CCZ through Kiribati-based Marawa Research and Exploration Ltd., and Tonga Offshore Mining Limited (TOML), which it acquired from Deep Sea Mining Finance Limited in April 2020.

Norway
In January 2024 Norway's parliament allowed multiple companies to prospect for DSM resources, mainly Seafloor Massive Sulfides (SMS), but also potentially Cobalt-rich crusts in the Norwegian EEZ, as well as on its continental shelf extension, along Mohns and Knipovich ridges Jan Mayen and Svalbard in the North Atlantic.

Norway's Institute of Marine Research recommended five to ten years of research before allowing mining. In late April 2024, the Norwegian Offshore Directorate invited interested parties to nominate blocks in this area for a first round of mineral exploration licences. First licence awards are expected for early 2025.

Three Norwegian start-up companies, Loke Marine Minerals, Green Minerals, and Adepth Minerals were expected to apply for licenses. In March 2023 Loke acquired Lockheed Martin subsidiary UK Seabed Resources Limited (UKSRL). This saw UKSRL's two PMN exploration licences in the CCZ, as well as its 19.9% stake in Ocean Minerals Singapore (OMS), an ISA contractor for PMNs in the CCZ. OMS is majority-controlled by Singaporean state-owned Keppel Offshore & Marine, now part of also Singaporean state-owned Seatrium.

Green Minerals is another Norwegian company which has expressed interested in mining seafloor massive sulfide (SMS) deposits in the Norwegian EEZ. In January 2023, Green Minerals signed a memorandum of understanding with the ISA to obtain an exploration licence for PMNs in the CCZ. In its May 2024 Capital Markets Day Presentation, it confirmed its ambitions to commence mining operations on SMS deposits on the Norwegian continental shelf and EEZ by 2028, as well as explore for PMNs in the CCZ in the future.

After in April 2024, the Norwegian government opened up an exploration area in the Norwegian and Greenland Seas, the World Wide Fund for Nature (WWF) declared that it would take legal action against the decision. According to the government, the seabed contains many resources including copper, zinc and cobalt, which are necessary for producing mobile phones, wind turbines, computers and batteries but as for now supplies are controlled by China or “authoritarian countries”. In June the energy ministry submitted "a proposal to announce the first licensing round on the Norwegian continental shelf for public consultation." According to the government, the aim is to understand if a sustainable deep sea mining there can occur. Otherwise, "deep-sea mining would not be permitted".

Extraction methods
Robotics and AI technologies are under development.

Remotely operated vehicles (ROVs) are used to collect mineral samples from prospective sites, using drills and other cutting tools. A mining ship or station collects the deposits for processing.

The continuous-line bucket system (CLB) is an older approach. It operates like a conveyor-belt, running from the bottom to the surface where a ship or mining platform extracts the minerals, and returns the tailings to the ocean.

Hydraulic suction mining instead lowers a pipe to the seafloor and pumps nodules up to the ship. Another pipe returns the tailings to the mining site.

Process
The three stages of deep-sea mining are prospecting, exploration and exploitation. Prospecting entails searching for minerals and estimating their size, shape and value. Exploration analyses the resources, testing potential recovery and potential economic/environmental extraction impacts. Exploitation is the recovery of these resources.

Resource assessment and pilot mining are part of exploration. If successful, "resources" attain a "reserves" classification. Bottom scanning and sampling use technologies such as echo-sounders, side scan sonars, deep-towed photography, remotely-operated vehicles, and autonomous underwater vehicles (AUV).

Extraction involves gathering material (mining), vertical transport, storing, offloading, transport, and metallurgical processing.

Polymetallic minerals require special treatment. Issues include spatial tailing discharges, sediment plumes, disturbance to the benthic environment, and analysis of regions affected by seafloor machines.

Environmental impacts
Deep sea mining (like all mining) must consider potential its environmental impacts. Deep sea mining has yet to receive a comprehensive evaluation of such impacts.

Environmental impacts include sediment plumes, disturbance of the bottom, and tailing disposition.

Technology is under development to mitigate these issues. This includes selective pick-up technology that leaves alone nodules that contain life and leaves behind some nodules to maintain the habitat.

The United Nations Environment Programme (UNEP) emphasizes the need for a comprehensive assessment of the environmental impacts of deep-sea mining, which targets polymetallic nodules at depths of 3-6.5 km, polymetallic sulphides at 1-4 km, and cobalt-rich ferromanganese crusts between <400 m and 3.5 km. Researchers and governments have raised significant concerns about the potential impacts on unique and fragile ecosystems, with only 24.9% of the deep seabed mapped. These ecosystems are essential for ocean and carbon cycling and are vulnerable to climate change. There are widespread calls for a moratorium on deep-sea mining until its environmental, social, and economic risks are fully investigated. The International Seabed Authority (ISA) aims to finalize exploitation regulations by 2025, and a new agreement under the UN Convention on the Law of the Sea (UNCLOS) on marine biodiversity was adopted on 19 June 2023.

Sediment plumes
Plumes are caused when mine tailings (usually fine particles) are returned to the ocean. Because the particles are fine (small and light), they can remain suspended in the water column for extended periods. Plumes can spread over large areas. Tailings increase water turbidity (cloudiness). Plumes form wherever the tailings are released, typically either near the bottom plumes or at the surface.

Near-bottom plumes occur when the tailings are pumped back down to the mining site. Depending particle size and water currents, surface plumes can spread widely. In shallow water, sediment can resuspend following storms, starting another cycle of damage.

Benthic disturbance
Removing parts of the sea floor disturbs the habitat of benthic organisms.

Preliminary studies indicated that the seabed requires decades to recover from even minor disturbances.

Nodule fields provide hard substrate on the bottom, attracting macrofauna. A study of benthic communities in the CCZ assessed a 350 square mile area with an ROV. They reported that the area contained a diverse abyssal plain megafaunal community. Megafauna (species longer than 20 mm) included glass sponges, anemones, eyeless fish, sea stars, psychropotes, amphipods, and isopods. Macrofauna (species longer than 0.5mm) were reported to have high species diversity, numbering 80 -100 per square meter. The highest species diversity was found among polymetallic nodules. In a follow-up survey in areas with potential for seabed mining, researchers identified over 1,000 species, 90% previously unknown, with over 50% dependent on polymetallic nodules for survival.

Noise and light pollution
Deep sea mining generates ambient noise in normally-quiet pelagic environments. Noise affects deep sea fish species and marine mammals. Impacts include behavior changes, communication difficulties, and temporary and permanent hearing damage.

DSM sites are normally pitch dark. Mining efforts may increase light levels to illuminate the bottom. Shrimp found at hydrothermal vents suffered permanent retinal damage when exposed to submersible floodlights. Behavioral changes include vertical migration patterns, ability to communicate, and ability to detect prey.

Impacts
Polymetallic nodule fields are hotspots of abundance and diversity for abyssal fauna. Sediment can clog filter-feeding organisms such as manta rays. Because they block the sun, they inhibit growth of photosynthesizing organisms, including coral and phytoplankton. Phytoplankton sit at the bottom of the food chain. Reducing phytoplankton reduces food availability for all other organisms. Metals carried by plumes can accumulate in tissues of shellfish. This bioaccumulation works its way through the food web, impacting predators, including humans.

One report states that biomass loss stemming from deep sea mining is estimated to be significantly smaller than that from mining on land. One estimate of land ore mining reports that it will lead to a loss of 568 megatons of biomass (approximately the same as that of the entire human population) versus 42 megatons of biomass from DSM. In addition, 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.

This kind of estimation does not take into account the recoverability of the situation: how long does nature need to reclaim an abandoned site. By contrast, a different study reported that deep sea mining would be approximately 25 times worse for biodiversity than land mining.

According to the International Union for Conservation of Nature : "Not only is deep-sea mining an energy-intensive industry with high greenhouse gas emissions, but disruption of the ocean floor, which is by far the largest carbon storage reservoir on Earth, can lead to reduced carbon sequestration as well as the release of large amounts of the potent greenhouse gas methane, exacerbating the climate crisis".

Laws and regulations
Deep-sea mining is not governed by a universal legal framework. Various norms and regulations have emerged both at an international level and within individual countries. The United Nations Convention on the Law of the Sea (UNCLOS) sets the overarching framework. The United States did not ratify the founding treaty.

International Seabed Authority
Activities in international waters are regulated by the International Seabed Authority (ISA). It was established in 1994. The United States is not a member of ISA. In 2021, China became the biggest contributor to ISA's administrative budget. Beijing also regularly donates to specific ISA funds. In 2020, China announced a joint training center with ISA in the Chinese port city of Qingdao. Continental shelves are subject to the jurisdictions of the adjoining states.

Regulations
The Area is governed by various treaties and regulations, based on the principles within UNCLOS (1982): outlined in Part XI and Annexes III and IV and found in the Implementation Agreement of 1994 and ISA regulations. ISA regulations are specific to each of polymetallic nodules, polymetallic sulfides and cobalt-rich ferromanganese crusts. The Area is the 'common heritage of all mankind', which means that its natural resources can be prospected, explored and exploited only in accordance with international regulations and that profits from these materials must be shared.

Prospecting does not require ISA approval and can be done by notifying ISA of the approximate area and formally declaring compliance with UNCLOS and ISA regulations.

Exploration requires ISA approval. Exploration contracts can last up to 15 years, extendable thereafter for periods up to 5 years. Contracts cover large areas: 150000 km2) for polymetallic nodules, 10000 km2 for polymetallic sulphides, and 300 km2 for cobalt-rich ferromanganese crusts.

Exploitation requires both states and private entities to obtain an approved contract from ISA, after evaluation by ISA's Legal and Technical Commission (LTC). Based on the LTC evaluation, the ISA Council approves or rejects the contract. Approval creates an exclusive right to prospect, explore, and exploit resources.

While the Area is primarily regulated by international law, non-state actors must be backed by a sponsoring state that is responsible and guarantees that the non-state actor abides by the contract and UNCLOS regulations. Sponsorship is defined by national law, which stipulates conditions, procedures, measures, fees and sanctions for non-state actor involvement.

Continental Shelves are delineated at 200 nautical-miles from the coast, but can be extended up to 350 nautical-miles. The continental shelf falls under coastal state jurisdiction, which has sovereign rights over natural resources within. No other state or non-state actor can prospect/explore/exploit resources in a continental shelf without the consent of the coastal state. If a coastal state allows DSM within its continental shelf, licenses with accompanying conditions and procedures must be defined by legislation.,

International law influences state legislation within continental shelves, as all states are obliged to protect and preserve the marine environment. All states must evaluate DSM's ecological effects within their jurisdiction. States must also ensure that DSM activities do not damage other states' environment and pollution cannot spread beyond the licensing state's jurisdiction. A contractor must make mandatory contributions to the ISA for mineral exploitation on an extended continental shelf as such extensions impact the 'common heritage of mankind'.

A DSM moratorium was adopted at the 2021 Global biodiversity summit. At the 2023 ISA meeting a DSM moratorium was enacted.

The United States did not ratify UNCLOS. Instead, it is governed by the Deep Seabed Hard Mineral Resources Act, which was originally enacted in 1980.

New Zealand regulates DSM via its 2011 Marine and Coastal Area Bill.

In 2021 Fauna and Flora International and World Wide Fund for Nature, broadcaster David Attenborough, and companies such as BMW, Google, Volvo Cars, and Samsung called for a moratorium.

History
In the 1960s, the prospect of deep-sea mining was assessed in J. L. Mero's Mineral Resources of the Sea. Nations including France, Germany and the United States dispatched research vessels in search of deposits. Initial estimates of DSM viability were exaggerated. Depressed metal prices led to the near abandonment of nodule mining by 1982. From the 1960s to 1984 an estimated US $650 million was spent on the venture, with little to no return.

A 2018 article 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".

2000s
In 2001, China Ocean Mineral Resources Research and Development Association (COMRA), received China's first exploration license.

Protests
In December 2023, the research vessel MV Coco was disrupted by Greenpeace activists blocking the collection of data to support a mining permit. Obstructing canoes and dinghies were countered by water hoses. The mining ship was conducting research for The Metals Company. The vessel MV Coco is owned by Magellan.

BMW pledged not to use DSM materials in its cars. In October 2023, the UK joined Canada and New Zealand in calling for a moratorium.

Alternatives
The environmental organization "The Oxygen Project" generally proposes, as an alternative to deep sea mining, "system change to sustainable alternative economic models that don't require infinite resource extraction from our environment". The Environmental Justice Foundation and Greenpeace proposed circular economy, public transport, and less car dependency, energy efficiency and resource efficiency.