Japan has quietly launched a high-stakes deep-sea operation that could redraw the global map for critical minerals and shake up its dependence on China.
Japan sends its drilling flagship to the abyss
The scientific drilling vessel Chikyu has left the port of Shizuoka bound for waters around Minamitori (also known as Minami-Torishima), a tiny atoll nearly 1,900 kilometres southeast of Tokyo.
For one month, the ship will attempt something no country has ever done at scale: continuously pump mud rich in rare earth elements from around 6,000 metres below the ocean surface straight up to the vessel.
Japan is testing whether a “technological jewel” can turn a remote patch of seabed into a strategic mineral lifeline.
The mission carries huge technical risk. It also carries political weight, as Tokyo tries to reduce its vulnerability to export decisions made in Beijing.
Why these deep-sea muds matter so much
Rare earths are a group of 17 metals used in products that sit at the heart of the digital and green economy: electric cars, smartphones, wind turbines, missiles and radars.
They are not truly rare in Earth’s crust, but they are rarely found in concentrations that make mining profitable. Processing them also needs complex chemical plants and strict environmental controls.
- Electric motors and wind turbines rely on neodymium, dysprosium and terbium magnets.
- LED screens and high-end displays use europium and yttrium for vivid colours.
- Medical imaging systems benefit from gadolinium and lutetium compounds.
Japan currently relies heavily on imports. Even after a decade of diversification, around two-thirds of its rare earth supply still comes from China, especially for the heavier, more strategic elements.
A previous export squeeze from China in 2010 convinced Tokyo that supply security for these metals is not just a trade topic but a national risk.
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Minamitori: a tiny atoll sitting on a huge potential prize
Minamitori itself is little more than a military outpost and a runway surrounded by coral. There is no real tourism industry and only a handful of people live there.
Below it, the picture changes. Japanese research cruises over the past decade have identified thick layers of mud on the seabed loaded with rare earths, especially heavy elements such as terbium and dysprosium.
This mud is soft, more like sticky clay than rock. Over millions of years, metals dissolved in seawater have settled slowly onto the ocean floor, building up a fine, mineral-rich layer.
That texture gives engineers a small advantage: soft mud is easier to vacuum than hard ore is to break and blast. The challenge lies in the depth.
The engineering challenge at 6,000 metres
At 6,000 metres, water pressure is around 600 times higher than at sea level. Temperatures are close to freezing, and any pipe system must withstand cold, pressure and strong ocean currents.
The Chikyu is one of the few ships on the planet designed for this sort of operation. It uses dynamic positioning thrusters to keep itself almost perfectly fixed above a chosen point on the seabed, even in rough seas.
From the ship, engineers will lower a long riser pipe down to the ocean floor. Pumps will then attempt to suck up the mud and send it in a continuous flow up to the deck.
If the mud clogs the pipes, the riser buckles, or the flow becomes unstable, the whole concept of deep mud pumping could be set back for years.
Onboard laboratories will analyse the material almost in real time. Geologists will look at metal grades, particle size, and how much work would be needed to separate the valuable elements from the rest.
Money, timelines and the 2027 milestone
Since 2018, Japan has poured about 40 billion yen (roughly £220–£250 million) into this deep-sea rare earth programme. Officials have avoided dramatic public promises and declined to publish firm resource figures.
The current cruise functions as a technology check. Policymakers and industry partners want answers to a few key questions:
- Can the riser system operate for long stretches without failure?
- Do flow rates stay high enough to make commercial projects realistic?
- Are the metal grades attractive when all processing costs are included?
If the mission goes well, a larger-scale test is pencilled in for around early 2027. Commercial production, if it ever comes, would likely start closer to the end of the decade.
How this fits into Japan’s broader rare earth strategy
Japan has been working on several fronts since the 2010 shock, when a maritime dispute led to a short-lived halt in Chinese rare earth shipments to Japanese firms.
| Supply source | Approximate share (2026) | Key characteristics |
| China | 60–70% | Crucial for heavy rare earths; tighter export controls in recent years |
| Australia | 15–20% | Long-term supply contracts; Japanese-backed processing capacity |
| Domestic recycling | 5–10% | Growing recovery from electronics and motors |
| Strategic stockpiles | Not publicly disclosed | Buffers against sudden trade disruptions |
| Subsea deposits (Minamitori and others) | 0% for now | Facing trials; potential production after 2030 |
Tokyo has supported Australian miner Lynas, funded pilot recycling plants, and quietly built emergency stocks. Yet economists argue that genuine security requires production that Japan can influence more directly, either at home or in waters it controls.
Deep-sea muds around Minamitori sit inside Japan’s exclusive economic zone, giving Tokyo far more legal and political control than it has over foreign mines.
Geopolitics at the bottom of the ocean
This mission unfolds against rising tension over critical minerals. China has already tightened export rules on several strategic materials, including some used for advanced chips and magnets.
Other countries, such as the US and EU members, are searching for new suppliers and backing alternative projects from Greenland to Brazil. Japan’s move into ultra-deep waters reflects the same anxiety: a sense that access to these metals could be used as leverage in future disputes.
If Japan shows that deep mud pumping works and can be managed responsibly, it may encourage similar projects in other exclusive economic zones. That would slowly erode China’s grip on supply and change the bargaining power of countries that rely on imported magnets, batteries and high-tech components.
Environmental questions that still lack clear answers
While the current mission focuses on technology and geology, environmental questions linger in the background.
Pumping mud from 6,000 metres will create plumes of fine particles near the seabed and possibly higher in the water column, depending on where waste water is released. Those plumes could affect deep-sea organisms that scientists barely understand.
Noise, light from equipment, and accidental leaks of fuel or hydraulic fluid also raise concerns. Environmental groups argue that rules for deep-sea mining have not kept pace with the rush for critical minerals.
Supporters reply that Japan’s project targets mud in its own waters and could be regulated more tightly than operations in international seabed areas.
For now, Japanese authorities frame Minamitori as a research and demonstration zone. Long-term production decisions will likely hinge on environmental impact studies as much as on ore grades or market prices.
What “rare earths” and “heavy” elements actually mean
Despite the name, rare earth elements sit in a single row of the periodic table, from lanthanum to lutetium, with yttrium often grouped alongside them. Chemically, they behave in similar ways, which makes separating them expensive and energy-heavy.
They are usually split into “light” and “heavy” categories. Light rare earths, such as lanthanum, cerium and neodymium, are more common and already mined in several countries. Heavy rare earths, including terbium, dysprosium and lutetium, are scarcer and harder to source outside China.
Minamitori’s muds appear particularly rich in some of these heavy elements. That is why Japanese experts see them as a strategic resource, even if operating costs at 6,000 metres turn out high.
Possible futures if the project succeeds – or stalls
If the Chikyu mission delivers stable mud flows and promising lab results, Japan could move towards building dedicated production systems: larger pumping ships, offshore processing units, and onshore refineries tailored to seabed mud chemistry.
That scenario would not replace every tonne of Chinese supply. It could, though, give Tokyo a powerful safety valve during crises and offer Japanese manufacturers a domestic premium product for their most sensitive applications, such as defence systems or advanced motors.
If things go badly – repeated equipment failures, poor ore grades, or strong public resistance on environmental grounds – Japan will probably double down on other strategies: heavier investment in recycling, stronger alliances with Australia and the US, and greater emphasis on using less rare earth per device through smarter design.
For companies in Europe or North America, the outcome has knock-on effects. A viable Japanese deep-sea supply line could stabilise prices and encourage new magnet factories outside China. A failed test would reinforce the sense that, for at least another decade, Beijing’s position in this niche remains hard to challenge.
