Deep Sea Mining Part 1

The 21st century economy is being rebuilt on minerals. Every electric vehicle, battery, transmission line, data centre, wind turbine, advanced semiconductor and weapons system ultimately depends on enormous quantities of copper, nickel, cobalt, manganese, lithium and rare earth elements. The modern world is entering what can only be described as a new age of material intensity.

In the last 25 years alone, the total tonnage of materials humanity extracts from the Earth has more than doubled. Yet most forecasts suggest we need to at minimum double it again, and potentially triple over the next few decades simply to support global electrification, AI infrastructure, industrial growth and rising living standards. Some aggressive energy-transition scenarios imply an even larger expansion.

This is where the problem begins.

Good ore bodies are becoming harder to find. Ore grades are declining across many major mining districts. New mines increasingly require larger pits, more waste rock, bigger tailings dams, more water, more energy and more capital to produce the same tonne of metal. The mining industry is increasingly experiencing diseconomies of scale: each additional tonne of material often becomes more expensive and environmentally intensive, not less.

At the same time, many of the world’s remaining large terrestrial deposits sit beneath tropical forests, near densely populated regions, or inside geopolitically difficult jurisdictions. Nickel expansion is pushing further into Indonesian rainforest systems. Copper projects face water stress and social conflict across Latin America. Cobalt remains heavily concentrated in the Democratic Republic of Congo. Rare earth supply chains remain dominated by China.

Against that backdrop, attention has increasingly turned toward a frontier that, until recently, belonged more to science fiction than industrial policy: the deep ocean.

Thousands of metres below the surface, vast areas of the seabed contain polymetallic nodules, cobalt-rich crusts and rare-earth-rich muds holding many of the exact metals modern industrial systems are struggling to secure. In some cases, the quantities involved rival or exceed known terrestrial reserves.

This immediately creates a difficult but unavoidable question.

If the choice is not between mining and no mining, but between different forms of mining in different environments, should the deep ocean automatically be excluded? Or should it be assessed using the same comparative standards we apply everywhere else: total environmental footprint, carbon intensity, waste generation, biodiversity impact, geopolitical concentration and human cost?

That is the real purpose of this primer.

Part I examines what deep-sea mining actually is, how the industry developed, the scale of the resource potential, and why it has become strategically important. Part II explores the environmental debate itself: the nature of abyssal ecosystems, the risks and unknowns, the standards being proposed, how they compare to terrestrial mining, and the broader moral argument surrounding mineral supply in an electrifying world.

Part I — What is Deep-Sea Mining?

Deep-sea mining is often discussed as though it were a single activity. In reality, it refers to several very different types of mineral extraction taking place across radically different ocean environments and depths.

The first, and by far the most commercially important today, involves polymetallic nodules scattered across abyssal plains at depths of roughly 4,000–6,000 metres. These nodules are essentially loose rocks lying exposed on the seabed, rich in manganese, nickel, cobalt and copper. The largest known concentration sits within the Clarion–Clipperton Zone (CCZ), a massive region between Hawaii and Mexico covering roughly 4.5–6 million square kilometres.

Importantly, these nodules do not need to be blasted, drilled or excavated from hard rock. They are already sitting on the sediment surface. Most proposed mining systems therefore resemble highly engineered harvesting operations rather than conventional underground or open-pit mining. Large robotic collector vehicles would move slowly across the seabed, gathering nodules and a thin layer of sediment before pumping the material to a surface vessel through vertical riser pipes. A new emerging technology uses an AI guided submarine robotic system that selectively collecting nodules and returns them to the surface.

The second type of deep-sea mining targets seafloor massive sulphides around hydrothermal vent systems, typically between 1,500 and 3,000 metres depth. These are much more analogous to traditional hard-rock mining. Metal-rich sulphide deposits containing copper, zinc, gold and silver form around ancient volcanic systems, and extracting them would require mechanical cutting and fragmentation of the seabed itself. Because hydrothermal vents can host highly specialised ecosystems, this category is generally considered environmentally more invasive and controversial.

The third category involves cobalt-rich ferromanganese crusts coating underwater mountains known as seamounts, usually between 800 and 3,000 metres depth. These crusts accumulate over millions of years as thin mineral layers cemented directly onto rock surfaces. Mining them would likely require grinding or cutting the crust away from the underlying basalt, effectively strip-mining parts of submarine mountains.

There is also a fourth emerging category attracting growing attention: rare-earth-rich muds. Japan, for example, has identified large rare-earth deposits within its own Exclusive Economic Zone around Minamitorishima Island. These Japanese mud deposits sit at depths similar to abyssal nodule fields and may potentially be recovered by collecting shallow sediment layers rather than cutting solid rock. Like nodules, they represent a form of mineral harvesting at the sediment-water interface rather than conventional excavation.

This distinction matters because much of the public imagination still pictures deep-sea mining as underwater open-pit mining. The reality, at least for the dominant commercial focus today, is quite different. The leading projects under development are primarily targeting loose mineral deposits resting on some of the flattest, darkest and least biologically productive regions of the ocean floor.

From Scientific Curiosity to a New Mineral Frontier

Deep-sea mining did not suddenly appear as a futuristic idea dreamt up for the energy transition. The industry has been developing, quietly and intermittently, for more than half a century.

The story began in the 1870s, when the HMS Challenger expedition first dredged strange black nodules from the Pacific seabed. But it was during the Cold War era, particularly through the 1960s and 1970s, that governments and industrial consortia realised these “rocks” contained enormous concentrations of nickel, cobalt, copper and manganese. Attention rapidly focused on the Clarion–Clipperton Zone (CCZ), a vast abyssal plain between Hawaii and Mexico covering roughly 4.5–6 million square kilometres, around 1–1.5% of the entire global ocean floor.

What followed was effectively the first deep-sea mining boom. American, Japanese, German, French, Soviet and multinational consortia spent hundreds of millions of dollars developing prototype collection systems, metallurgical processing flowsheets and seabed mapping technologies. By the late 1970s, engineers were already recovering nodules from depths of 4,000–6,000 metres and testing vertical lifting systems capable of pumping ore slurry to surface vessels.

Then the industry stalled.

Metal prices weakened, the Cold War ended, financing dried up, and perhaps most importantly, nobody could agree who actually owned the seabed. That legal vacuum ultimately led to the creation of the International Seabed Authority (ISA) under the UN Convention on the Law of the Sea.

Under UNCLOS, coastal states control what is known as an Exclusive Economic Zone, or EEZ, extending roughly 200 nautical miles from their coastline. Within that zone, countries have sovereign rights over seabed resources, fisheries and energy development. Beyond that boundary lies “the Area”: international waters and seabed governed collectively through the ISA as the so-called “common heritage of humankind.”

That distinction matters enormously. Japanese rare-earth mud projects near Minamitorishima, for example, sit within Japan’s EEZ and are therefore controlled directly by Japan. The Cook Islands, Norway and others are developing similar domestic frameworks within their own waters. The CCZ, by contrast, sits largely in international waters and therefore falls under ISA jurisdiction.

Today the ISA has issued roughly 30 exploration contracts, including around 19 for polymetallic nodules, most of them concentrated in the CCZ. China holds the single largest position through multiple state-backed entities, alongside licences sponsored by countries including Russia, India, Japan, Korea, France, Belgium, Germany, the UK and several Pacific Island states. Many of these licences are not new. Some trace their origins back nearly 30 years to the earliest ISA exploration regimes in the 1990s, meaning contractors have already spent decades collecting geological, environmental and engineering data across enormous parts of the Pacific seabed.

And while public discussion often implies the industry remains hypothetical, the reality is that large parts of the sector have already moved well beyond basic exploration. Companies such as The Metals Company (via NORI) and Belgium’s GSR have completed integrated pilot mining tests recovering thousands of tonnes of nodules from the seafloor and monitoring sediment plumes and equipment performance in real-world conditions. China, meanwhile, has been aggressively expanding both exploration and technology development globally, including testing collector systems, submersibles and seabed engineering technologies across multiple regions. Unlike Western-listed companies operating under public disclosure regimes, however, Chinese state-backed programmes release relatively little detailed operational data commercially or publicly, making the true extent of their progress difficult to assess externally.

What is clear is that deep-sea mining is no longer theoretical technology. The engineering challenge has largely shifted from “can it work?” to “under what political and regulatory conditions will it be allowed to operate?”

The Regulatory Deadlock and the Global Split

That question has now triggered one of the most politically divisive resource debates of the modern era.

The ISA was originally intended to create a workable international framework allowing seabed minerals to be developed while protecting the marine environment and distributing economic benefits globally. Instead, after more than three decades, the organisation remains locked in prolonged negotiations over a Mining Code that still does not fully exist.

As of 2025–2026, no commercial exploitation licence has been granted in international waters despite billions of dollars having already been spent on exploration, environmental baseline studies, vessel systems, robotics and metallurgical testing. Contractors and sponsoring states increasingly argue that the UN system has failed to convert decades of scientific and financial investment into a functioning regulatory pathway.

Into that vacuum stepped a growing NGO-led campaign calling for a moratorium, precautionary pause, or outright ban on deep-sea mining. Several European countries, along with some Pacific and Latin American states, have aligned themselves with this position, arguing that ecological understanding of abyssal ecosystems remains incomplete and commercial mining should not proceed without stronger safeguards.

But the global picture is far more divided than public narratives often suggest.

China, India, Japan, Korea and Russia continue to actively support commercial development. Small island developing states such as Nauru, Tonga and Kiribati view deep-sea mining not as an abstract environmental debate, but as a potentially transformational economic opportunity capable of generating royalties, infrastructure investment and strategic leverage in a resource-constrained world. Many of these nations sponsored ISA contractors in good faith, spent millions supporting exploration programmes, and now argue that the UN system is effectively paralysed by political activism and endless procedural delay.

The United States has increasingly moved in the same direction, it never ratified UNCLOS, therefore it is not strictly bound by the treaty. Washington has begun revitalising its domestic deep-sea mining framework under NOAA through the Deep Seabed Hard Mineral Resources Act, partly driven by concern that the West risks falling behind China in yet another critical mineral supply chain.

That geopolitical fracture became unmistakable when The Metals Company announced plans to pursue a US NOAA permitting pathway rather than continue relying exclusively on the ISA process. In effect, one of the world’s most advanced deep-sea mining companies concluded that the UN-centred system had become too politically stalled and NGO-dominated to provide a credible route to commercial production.

This is now the core reality of deep-sea mining. The resources are known. The technologies largely exist. The exploration data has been accumulated over decades. The real battle is no longer geological or even engineering.

It is geopolitical.

And beneath the moral language surrounding the debate sits a much harder strategic question: if the world requires dramatically more nickel, copper, cobalt and manganese for electrification, AI infrastructure, defence systems and industrial growth, who will control the next frontier of mineral supply — and under whose rules?

Why the Deep Sea Matters: The Scale of the Resource

The reason deep-sea mining has become such a geopolitical flashpoint is simple: the scale of the resource base is enormous.

Not “interesting.” Not “incremental.” Potentially civilisation-scale.

Polymetallic nodules scattered across abyssal plains contain many of the exact metals modern industrial systems are struggling to secure: nickel, cobalt, copper and manganese. These are the core inputs into batteries, electrical systems, defence technologies, AI infrastructure, transmission networks and industrial alloys. And unlike many terrestrial deposits, the metals already occur together in a single ore body sitting exposed on the seabed, rather than buried beneath forests, villages or hundreds of metres of rock.

Globally, scientists estimate total polymetallic nodule resources may exceed 1 trillion tonnes. The Clarion–Clipperton Zone alone is thought to contain roughly 20 billion tonnes of nodules spread across the seabed between Hawaii and Mexico.

The numbers inside those nodules are staggering.

Estimates for the CCZ alone commonly include:

• More than 5–6 billion tonnes of manganese

• Around 250–350 million tonnes of nickel

• Roughly 200–300 million tonnes of copper

• More than 40–70 million tonnes of cobalt

To understand why that matters, global annual nickel production today is roughly 3.5 million tonnes per year. Global cobalt production is only around 230,000 tonnes annually. The contained cobalt in the CCZ may therefore represent centuries of current global production.

In some assessments, the cobalt contained in CCZ nodules alone exceeds all known economically recoverable terrestrial cobalt reserves combined several times over.

Rare earths tell a similar story.

Within Japan’s EEZ around Minamitorishima Island, researchers have identified large accumulations of rare-earth-rich muds containing potentially tens of millions of tonnes of rare earth oxides. Importantly, these include both light and heavy rare earths, the latter being among the most strategically important and hardest to secure materials in the global economy.

In other words, countries are not exploring the deep sea because it is scientifically interesting. They are exploring it because the numbers are becoming impossible to ignore.

None of this means these deposits are automatically economic. Resources are not reserves. A deposit still has to be technically recoverable, environmentally permitted and commercially viable. Deep-sea mining remains expensive, politically contested and technologically challenging.

But from the perspective of the mineral imperative, the logic is increasingly obvious.