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Everything you Need to Know about Deep-Sea Mining
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“ We’re edging closer to a new frontier in resource extraction - deep-sea mining. As minerals critical to the energy transition become harder to source on land, attention has turned to the vast, metal-rich plains of the ocean floor. The promise? Access to nickel, cobalt, manganese, and other key materials locked away in polymetallic nodules scattered across the deep seabed. The risk? Irreversible damage to one of Earth’s most fragile and least understood ecosystems. ”
While interest in deep-sea mining has surged, global governance has struggled to keep pace. A July 2023 deadline passed without the adoption of binding international regulations, leaving the industry in a legal grey zone. As of 2025, the International Seabed Authority (ISA) is still racing to finalise a mining code amid mounting political pressure, scientific warnings, and calls for a global moratorium.
In this article, we’ll explore what deep-sea mining is, the international laws (or lack thereof) that govern it, and why so many scientists, countries, and companies are urging caution before mining the ocean floor.
What is deep-sea mining? A summary
“ Deep-sea mining refers to the process of extracting valuable mineral resources from the ocean floor, typically at depths greater than 200 metres. These minerals, including cobalt, nickel, copper, and rare earth elements, are found in rich concentrations on the seabed, often in international waters far from any coastline. ”
As global demand for these metals intensifies, particularly for use in batteries, renewable technologies, and electronics, mining companies have turned their sights to the ocean as the next frontier. While traditional seabed mining has taken place in shallow coastal waters for decades (such as for tin, sand, or diamonds), deep-sea mining ventures are targeting far more remote and fragile ecosystems across the global oceans.
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What resources are found in the deep sea?
“ The deep ocean floor is a rich mineral resource, containing metals essential to the green energy transition, many of which are now in short supply or concentrated in politically sensitive regions on land. ”
These materials typically accumulate over millions of years in three geological formations: polymetallic nodules, polymetallic sulphides, and cobalt-rich crusts.
Here’s a quick overview of the key resources and why they’re in demand:
| Resource | Where it's found | Why it's valuable |
|---|---|---|
| Nickel | Polymetallic nodules, sulphide deposits | Used in lithium-ion batteries for electric vehicles and renewable energy storage |
| Cobalt | Polymetallic nodules, cobalt-rich crusts | Essential for battery performance, especially in EVs; currently sourced mainly from the DRC |
| Copper | Polymetallic nodules, sulphide deposits | Critical for electrical wiring and green infrastructure like wind turbines and solar panels |
| Manganese | Polymetallic nodules | Used to strengthen steel and in battery chemistry |
| Rare Earth Elements | Cobalt-rich crusts | Used in electronics, wind turbines, and permanent magnets for electric motors |
| Zinc & Gold | Polymetallic sulphide deposits | Used in electronics, alloys, and as a store of value (gold); zinc also supports corrosion resistance |
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Where are these minerals found?
The minerals targeted by deep-sea mining aren’t spread evenly across the ocean floor; they’re concentrated in specific geological formations in a handful of deep-sea regions. Most current exploration activity is focused on international waters, beyond the jurisdiction of any single country.
Here are the key deep-sea mining regions:
Clarion-Clipperton Zone (CCZ)
Located in the Central Pacific Ocean between Hawaii and Mexico, the CCZ is by far the most heavily targeted area for deep-sea mining. Spanning around 4.5 million square kilometres, it contains some of the world's highest concentrations of polymetallic nodules rich in nickel, cobalt, copper, and manganese.
Mid-Atlantic Ridge
This underwater mountain range, stretching from the Arctic to the South Atlantic, hosts hydrothermal vent fields that contain polymetallic sulphides rich in copper, zinc, and gold. It’s of growing interest for sulphide mining.
Indian Ocean Ridge systems
Regions such as the Southwest Indian Ridge and Central Indian Ridge are also home to hydrothermal activity and associated sulphide deposits.
Western Pacific Seamounts
The flanks of underwater mountains in the Western Pacific are known to host cobalt-rich ferromanganese crusts. Countries like Japan and South Korea have been exploring seamounts in their own Exclusive Economic Zones (EEZs), where national laws apply.
How is deep-seabed mining carried out?
There are three primary types of deep-sea mining currently being explored. Each targets a different kind of mineral deposit, formed over millions of years in distinct geological environments.
Polymetallic nodule mining
Polymetallic nodules are small, potato-sized lumps scattered across vast stretches of flat seabed, particularly in the Clarion-Clipperton Zone. These nodules contain high concentrations of nickel, cobalt, copper, and manganese.
To harvest them, remote-controlled vehicles are sent to the ocean floor to collect nodules by vacuuming the top layer of sediment (typically the upper 5–10 cm). The nodules are then pumped to the surface through a vertical riser pipe system.
Polymetallic sulphide mining
These metal-rich deposits form around hydrothermal vents – underwater volcanic systems that emit mineral-laden fluids. As the hot fluids mix with cold seawater, metals such as copper, zinc, iron, and even gold precipitate and build up into chimney-like structures.
Mining involves deploying cutting or drilling equipment to fragment and collect the mineral deposits directly from the seabed. These sites are usually found at depths of 1,000 to 4,000 metres along mid-ocean ridges.
Cobalt-rich crust mining
Cobalt crusts form on the flanks of underwater mountains, where minerals slowly precipitate out of seawater and accumulate on exposed rock surfaces. These crusts are rich in cobalt, rare earth elements, and titanium.
Mining would involve robotic cutting tools that scrape or shear off the outer layer of the rock face, typically at depths between 800 and 2,500 metres.
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Why is deep-sea mining a concern for the environment?
“ The deep ocean is one of the least understood and most fragile ecosystems on the planet. While deep-sea mining promises access to critical minerals, scientists warn that it could come at a devastating ecological cost, with many of the impacts from future mining operations likely to be irreversible on human timescales. ”
Here’s a breakdown of the key environmental concerns linked to the different types of deep-sea mining:
Habitat destruction
Harvesting polymetallic nodules involves removing the top layer of the deep-sea bed, leading to the destruction of habitats for numerous species. A study revealed that even 44 years after experimental mining, the sea floor in the Clarion-Clipperton Zone (CCZ) showed little or no recovery, with long-lasting changes in sediment and reduced megafauna diversity.
Biodiversity loss
The CCZ is home to biodiverse deep-sea creatures, with approximately 90% of species discovered in the area being new to science. Disturbing this environment could lead to the loss of unknown species and disrupt ecological balance.
Seabed mining tracks
Seabed mining tracks created by nodule collection remain visible for decades, marking long-term disruption to sediment structure and species recovery.
Ecosystem disruption
Hydrothermal vents are biodiversity hotspots, often supporting rare and endemic life. Mining activities around these vents can destroy these unique ecosystems and specialised organisms. These communities are adapted to extreme conditions and may not recover if disturbed.
Scientific loss
Mining would destroy deep-sea ecosystems that remain largely unexplored, reducing opportunities for biological discovery and medical research.
Long-formed ecosystems
These coral and sponge systems may have taken thousands of years to form. Extracting cobalt-rich crusts from seamounts can harm slow-growing corals and sponges that provide habitat for diverse marine life.
Difficult access, even harder recovery
The removal of these structures may have long-term ecological consequences. Once damaged, there is no proven way to restore these seafloor habitats.
Sediment plumes
Mining stirs up clouds of fine sediment that can drift for kilometres, potentially smothering corals, sponges, and filter-feeders. Research indicates that sediment disturbances from mining can have significant impacts on ecosystems beyond the immediate mined areas.
Midwater discharges
Wastewater released from mining vessels can cloud the ocean's midwater column, impacting plankton, fish, and marine mammals that depend on clear, nutrient-rich layers.
Noise and light pollution
Mining machinery generates continuous low-frequency noise, vibrations, and artificial light, potentially affecting marine species that rely on sound for communication and navigation.
Chemical pollution
Mining activities may release toxic substances, including heavy metals, into the marine environment, posing risks to marine life and potentially entering the food chain.
Recent research has uncovered a surprising discovery: metal-rich nodules may play a role in producing oxygen in the deep ocean through geochemical reactions. Removing these nodules could disrupt not just the habitat, but also oxygen levels in certain parts of the ocean floor.
Scientists have already warned that deep-sea mining will cause permanent damage to ocean ecosystems, which will also have a knock-on effect when it comes to coastal communities who rely on the ocean for their livelihoods. Given the geographic focus of deep-sea mining activities, it is Pacific Island communities that are likely to be most affected. Mining has the potential to affect fish populations and marine ecosystems, something that these communities rely on for food and income.
“ The scientific consensus is increasingly clear: the environmental risks of deep-sea mining are high, poorly understood, and largely irreversible. With recovery timelines spanning centuries, or longer, many researchers argue that it’s too soon to begin large-scale mining without significantly more ecological data and regulatory safeguards in place. ”
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What laws govern deep-sea mining?
The deep ocean beyond national borders is considered the “common heritage of mankind” under international law, which means it can’t be claimed or exploited by any one country. But who gets to decide what happens there?
The answer lies in a United Nations treaty and the international body responsible for its implementation: the United Nations Convention on the Law of the Sea (UNCLOS) and the International Seabed Authority (ISA).
The legal framework:
UNCLOS
Adopted in 1982, UNCLOS is the key treaty that governs the use of the world's oceans. It defines the rights and responsibilities of nations with respect to marine resources, including the seabed.
The Area
Under UNCLOS, the seabed beyond national jurisdiction is known as “the Area”, and the mineral resources found there are designated as the "common heritage of mankind". This principle requires that benefits from any exploitation be shared fairly and that environmental protection is a priority.
The International Seabed Authority (ISA)
Headquartered in Kingston, Jamaica, the ISA is the body responsible for regulating all mining activities in the Area. It oversees:
- The granting of exploration licences
- The development of environmental guidelines
- The drafting of a comprehensive Mining Code to govern commercial exploitation
The 2023 deadline and what happened next
In 2021, the Pacific Island nation of Nauru triggered a provision in UNCLOS known as the “two-year rule”, forcing the ISA to complete regulations for commercial mining by July 9, 2023. If regulations were not adopted by that date, Nauru would have the right to submit a mining application, even in the absence of a legal framework.
As expected, the ISA missed the 2023 deadline. Despite years of negotiations, member states could not agree on key provisions, particularly around environmental safeguards, benefit-sharing mechanisms, and liability for damage.
What’s the status as of 2025?
No mining code (yet)
As of May 2025, the ISA has still not finalised the exploitation regulations – a delay that has created legal uncertainty for the deep-sea mining industry. A full first reading of the draft Mining Code was completed in 2024, but key points remain unresolved. ISA member states aim to finalise the text by the end of 2025.
No exploitation contracts approved
No country or company has yet been granted permission to begin commercial deep-sea mining in international waters.
Applications could still come
Nauru and its sponsored company, The Metals Company, have indicated plans to submit a mining application in mid-2025. If they do so before a Mining Code is finalised, the ISA will be legally obliged to consider it, potentially under provisional procedures.
Temporary protections
ISA members have agreed not to rush approvals and have committed to handling any applications cautiously while negotiations continue. However, there is no legal moratorium in place.
Growing calls for stronger protections
In the absence of binding exploitation rules, many countries, scientists, and civil society organisations are pushing for a moratorium or pause on deep-sea mining.
- As of 2025, more than 30 countries - including France, the UK, Germany, Canada, New Zealand, and several Pacific nations - have formally backed a call to halt deep-sea mining until the risks are better understood and stronger regulations are in place.
- The European Parliament has passed multiple resolutions calling for a moratorium, and major companies like Google, BMW, Samsung, and Volvo have pledged not to use minerals sourced from the deep ocean.
Exploration vs exploitation: what's the difference?
Although no country or company has been granted permission to start deep-sea mining, many have already secured exploration contracts from the International Seabed Authority (ISA).
What’s the difference?
- Exploration contracts give companies or state bodies the right to conduct surveys, sampling, and environmental baseline studies in a defined area of the seabed. These contracts typically last 15 years and allow the contractor to map mineral deposits and test mining technology, but not extract commercially.
- Exploitation contracts, which have not yet been granted, would allow full-scale commercial mining. To proceed, companies would need to apply for and be granted a commercial recovery permit, based on environmental assessments and ISA approval.
“ As of 2025, the ISA has granted 31 exploration licences covering over 1.5 million square kilometres of international seabed, mostly in the Clarion-Clipperton Zone. ”
Why does exploration still raise concerns?
Even though exploration is not full mining, it’s not impact-free. Scientists warn that:
- Seafloor sampling and equipment testing can disturb sediment and benthic organisms
- Deep-sea trials (such as those conducted by The Metals Company in 2022) already involve nodule collection and plume generation
- There is a risk of “regulatory momentum” - once companies invest in exploration, they are more likely to pressure regulators to approve mining later
Environmental groups argue that exploration licences create a legal and financial pathway toward exploitation, and that allowing large-scale exploration before completing the Mining Code undermines the precautionary principle.
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Who is supporting deep-sea mining?
Under UNCLOS, only governments can apply for mining rights, but they can sponsor deep-sea mining companies to act on their behalf. As of 2025, over 30 exploration contracts have been issued by the International Seabed Authority (ISA), most of them sponsored by these countries:
| Country | Companies/Entities Sponsored | Type of Mining |
|---|---|---|
| Nauru | Nauru Ocean Resources Inc. (subsidiary of The Metals Company) | Polymetallic nodules |
| Tonga | Tonga Offshore Mining Ltd (also linked to The Metals Company) | Polymetallic nodules |
| Kiribati | Marawa Research and Exploration Ltd (TMC-affiliated) | Polymetallic nodules |
| India | Ministry of Earth Sciences (Gov’t body) | Polymetallic sulphides |
| China | China Ocean Mineral Resources R&D Association (COMRA) | Nodules, sulphides, cobalt crusts |
| Russia | Yuzhmorgeologiya (state company) | Polymetallic nodules |
| Japan | Japan Oil, Gas and Metals National Corporation (JOGMEC) | Cobalt crusts, sulphides (EEZ and ISA) |
| South Korea | Korea Institute of Ocean Science and Technology (KIOST) | Polymetallic nodules |
| France | Institut français de recherche pour l'exploitation de la mer (IFREMER) | Polymetallic sulphides |
| Germany | Federal Institute for Geosciences and Natural Resources (BGR) | Polymetallic nodules |
| Belgium | Global Sea Mineral Resources (GSR) | Polymetallic nodules |
| United Kingdom (until 2023) | UK Seabed Resources (formerly Lockheed Martin; sold to Norway’s Loke Marine Minerals in 2023) | Polymetallic nodules |
Most current exploration contracts focus on the Clarion-Clipperton Zone (CCZ) in the Pacific.
Who is opposed to deep-sea mining?
As of 2025, more than 30 countries have officially called for a moratorium, pause, or outright ban on deep-sea mining in international waters. Their reasons range from scientific uncertainty to environmental concerns and Indigenous rights.
| Country | Position | Details |
|---|---|---|
| France | Ban | President Macron called for a total ban in 2022 |
| Germany | Moratorium | Supports a pause until risks are better understood |
| United Kingdom | Moratorium | Reversed earlier support in 2023 |
| Canada | Moratorium | Strong supporter of environmental safeguards |
| New Zealand | Moratorium | Advocates ocean protection |
| Spain | Moratorium | Formally opposed at ISA |
| Portugal | Legal moratorium (national waters) | Imposed a 25-year ban in its EEZ in 2025 |
| Chile, Brazil, Ireland, Switzerland | Moratorium | Public declarations in ISA sessions and global forums |
| Palau, Fiji, Samoa, Vanuatu, Tuvalu | Moratorium | Pacific nations advocating protection of marine ecosystems |
Companies that have distanced themselves from deep-sea mining
Several major companies and investors have publicly pledged not to use or fund deep-sea minerals, at least not until stronger environmental safeguards are in place.
Google, BMW, Volvo Group, Samsung SDI, and Rivian have all signed the World Wildlife Fund’s moratorium pledge, committing not to source metals from the seabed.
Maersk took a firmer stance by divesting from The Metals Company in 2023, while Lockheed Martin exited the industry altogether, selling its subsidiary UK Seabed Resources that same year.
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A growing divide
- The divide is no longer just North vs South, it cuts across developed and developing nations, often reflecting environmental priorities vs economic opportunity.
- Some Pacific Island nations both sponsor mining (e.g. Nauru, Tonga) and oppose it (e.g. Palau, Fiji) — underscoring internal regional tensions over environmental and economic futures.
- The ISA itself remains under scrutiny, with critics claiming it promotes mining interests while being responsible for environmental protection.
A Complex Trade-Off
Deep-sea mining presents a dilemma with no easy answer. On one hand, the world urgently needs more minerals like nickel, cobalt, and rare earth elements to support the green transition. On the other hand, the risks to the deep ocean are profound and possibly irreversible.
The case for deep-sea mining
Proponents argue that if we’re serious about ditching fossil fuels, we’re going to need a lot more metals and fast. Minerals like nickel and cobalt are critical for batteries, wind turbines, electric vehicles, and large-scale energy storage. The problem? Current terrestrial mining practices come with their own serious environmental and human costs:
Less land destruction
Extracting these minerals on land often means clearing forests, polluting water sources, and generating high emissions. In some regions, it also fuels conflict and displaces Indigenous communities.
Higher-grade ores
Polymetallic nodules are often more concentrated in valuable metals than typical land-based ores, meaning less waste rock and potentially fewer emissions per tonne of metal extracted.
Diversified supply
Today, many of these critical minerals are sourced from just a handful of countries. Deep-sea mining could diversify supply and reduce dependence on politically unstable regions.
Some see it as a potential “lesser evil” - a way to get the minerals we need without further degrading life on land.
The case against it
But many scientists argue that we know too little about the deep sea to mine it responsibly and that moving ahead now could cause irreversible harm.
Ecosystem loss is likely and long-lasting
The deep sea is home to fragile ecosystems that evolve slowly and may never fully recover from disturbance. Many of the species that live on or around nodules are still unnamed, and mining could wipe them out before we even begin to understand their role.
Carbon and nutrient cycles could be disrupted
The seafloor plays a role in storing carbon and recycling nutrients. Disturbing it could release greenhouse gases and alter ocean chemistry.
Scientific knowledge is still limited
The deep sea remains one of the least explored environments on Earth, and many of the species living there have yet to be formally described. Without robust baseline data, scientists warn that we simply can’t predict the full ecological consequences of mining, or reverse them once they occur. Organisations like the Natural Environment Research Council continue to fund deep-sea research to fill these knowledge gaps, but much of the seabed remains unexplored.
A difficult decision
This tension is at the heart of the debate: how do we secure the materials needed to build a cleaner, net-zero energy future without undermining the planet in the process?
There’s no perfect solution. But while proponents of deep-sea mining argue it’s necessary for the energy transition, many scientists counter that we know too little about the deep sea to mine it responsibly, and that moving ahead now could cause irreversible harm. Others argue that instead of racing to mine the seafloor, we should invest more heavily in:
- Battery recycling
- Alternative materials
- Better resource efficiency
“ At its core, deep-sea mining is a question of risk vs. necessity. And right now, the science suggests we should tread very carefully. ”
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