Japan prepares deep sea rare earth trials as China tightens export controls

A 6,000 meter test of Japan's mineral security

Japan plans to begin test mining in January 2026 in waters near Minamitorishima, a remote atoll roughly 1,900 to 2,000 kilometers southeast of Tokyo. The target is mud containing rare earth elements at depths of 5,000 to 6,000 meters. Government planners describe the operation as a world first attempt at this depth, intended to build a domestic source of metals used in electric vehicles, wind turbines, smartphones, medical equipment and advanced weapons.

The timetable stretches beyond the first voyage. A pilot system planned for January 2027 would recover about 350 tonnes of mud a day. Supply to private companies could begin around 2028 if extraction, processing and costs meet the project's requirements. As of October 18, 2025, these are targets, with the engineering and commercial tests still ahead.

Japanese researchers have estimated roughly 16 million tonnes of rare earth resources around Minamitorishima. A 2018 analysis described quantities sufficient to supply certain elements for approximately 420 to 780 years, depending on the element. Some concentrations exceed those found in typical deposits on land, and the mud contains valuable medium and heavy rare earths.

China's tighter export controls have made those resources more urgent for Japan. Beijing restricted several medium and heavy rare earths in April, then widened its controls on October 9. Japanese manufacturers have already experienced interruptions: controls earlier this year forced Nissan and Suzuki to briefly stop certain assembly operations.

Tokyo's immediate aim is a dependable alternative supply, even if the first material costs more than imports. Reaching that goal requires a chain of equipment and factories stretching from the Pacific seabed to manufacturers that need precisely processed metals.

Why a small group of metals matters so much

Rare earths are a family of 17 metallic elements used to make electronics and clean energy equipment smaller, stronger and more efficient. Their individual properties determine where they are useful, so securing one element does not automatically resolve shortages of another.

Neodymium, praseodymium and samarium are used in powerful permanent magnets, including those inside electric vehicle motors and wind turbine generators. Dysprosium and terbium help magnets retain their performance at high temperatures, an important requirement in vehicle drive systems and aerospace components. Yttrium, europium and gadolinium have uses in displays, lasers, medical imaging and specialized alloys.

China dominates both mining and the processing that turns raw resources into oxides, metals and magnet alloys. Manufacturers need those processed materials, making separation and refining a critical supply bottleneck. Export restrictions can disrupt production planning, move prices sharply and expose factories to political disputes.

Japan experienced that vulnerability in 2010, when a diplomatic clash triggered a sharp fall in Chinese rare earth exports to Japan. China then supplied about 90 percent of Japanese needs. Contracts in Australia, India and Kazakhstan, together with investment in refineries in Malaysia and Vietnam, helped reduce that share to just under 60 percent.

The change amounts to a reduction of roughly 30 percentage points, using the approximately 90 percent starting share and the current level below 60 percent. China nevertheless remains Japan's largest source, and the interruptions at Nissan and Suzuki show how a shortage of specialized materials can reach assembly lines.

What lies beneath the waters near Minamitorishima?

Minamitorishima's resource is fine mud rather than a conventional deposit of rock on land. Surveys and sediment cores have identified layers containing an unusual mixture of rare earths, including relatively high concentrations of medium and heavy elements. Dysprosium and terbium are especially important, alongside neodymium and gadolinium.

Many deposits on land outside China contain larger proportions of lighter rare earths. The heavier elements in the Minamitorishima mud are scarcer and command higher prices, giving the deposit particular strategic value. The mud also contains relatively little radioactive thorium and uranium compared with many ores on land, reducing some processing hazards and waste handling challenges.

The target area lies roughly 100 to 150 kilometers from the atoll, within Japan's exclusive economic zone. That location gives Tokyo control over exploration and production, while placing operations far from industrial centers. Distance complicates shipping, maintenance and emergency response; the depth pushes offshore machinery toward the limits of current engineering.

Japan's seabed resources extend beyond rare earth mud. A separate survey led by Japanese researchers identified more than 200 million tonnes of manganese nodules in the wider Pacific at depths around 5,500 meters. Those nodules contain an estimated 610,000 tonnes of cobalt, equivalent to roughly 75 years of Japanese consumption at current rates, and 740,000 tonnes of nickel, equivalent to about 11 years of domestic demand.

Nodules sit on the seabed, while the Minamitorishima project must collect mud and pump it upward mixed with water. Engineers estimate that a future operation would need to collect several thousand tonnes of mud daily to reach an economic scale, well beyond the planned pilot's capacity.

The timetable from sampling to factory supply

A national platform for innovative ocean developments manages the government project, working with the Japan Agency for Marine-Earth Science and Technology. The agency's research vessels, including the drilling ship Chikyu, provide the ability to handle heavy equipment and long strings of pipe.

The first operation will test whether the system can collect and lift material reliably. One operation is expected to recover about 35 tonnes of mud for laboratory work, potentially containing a few dozen kilograms of rare earth elements. The planned 350 tonnes a day in the pilot phase would provide enough material to test separation and refining at a larger scale.

• 2010: A diplomatic clash triggered a sharp fall in Chinese rare earth exports to Japan, which then depended on China for about 90 percent of its needs.
• 2018: Japanese scientists described the Minamitorishima resource as sufficient to supply certain rare earths for about 420 to 780 years.
• April 2025: China tightened export controls on several medium and heavy rare earths.
• October 9, 2025: Beijing widened those controls and added more elements.
• January 2026: Japan plans to begin test mining at depths of 5,000 to 6,000 meters.
• January 2027: A pilot system is planned to recover about 350 tonnes of mud daily.
• Around 2028: Material could begin reaching private companies if the project meets its technical and commercial requirements.

The progression gives Japan time to learn how much usable material it can recover and how reliably the machinery operates. Early output would be modest, with expansion dependent on the pilot's performance.

How do engineers lift mud through six kilometers of water?

Chikyu and the other equipment must perform a demanding task: lower pipes to the seabed, collect mud and move it to the surface through a water column as much as 6,000 meters deep. The mud has a claylike consistency, so operators must mix it with seawater to form a slurry, a mixture that can flow through a pipe.

The pipe would be longer than those typically used in deepwater oil operations. Many oilfield risers reach about 3,500 meters. Extending that length adds weight and increases exposure to vibration. Engineers have modeled the pipe's movements to avoid resonance, a repeated motion that can build in strength and cause metal fatigue.

Equipment on the seabed must be sturdy and relatively simple because repairs at that depth would be slow and risky. Japanese teams have developed machinery to break the mud into particles roughly 4 millimeters or smaller, helping it pass through pumps while limiting energy consumption.

The seabed itself creates another engineering problem. Weak sediment layers beneath the target mud could allow heavy machinery to sink or foundations to fail. System designers have considered those layers and adjusted the equipment's foundations accordingly.

Reliable collection is only part of the test. Operators must keep the slurry moving steadily through the long pipe, manage the loads on the vessel and equipment, and bring enough material aboard for meaningful processing trials. Each stage affects how much mud can ultimately be recovered in a day.

Why collecting the mud is only the first step

Once the slurry reaches the ship, operators will remove water and transport the material to mainland Japan for analysis and separation. Elements such as dysprosium, terbium, neodymium and gadolinium must then be turned into products that industrial customers can use.

Rare earth separation requires repeated solvent extraction stages, careful control of acidity through pH measurements, and strict quality checks. The process separates the elements and achieves the purity needed for demanding applications, including powerful magnets and electronic components. Further work turns separated material into oxides, metals and magnet alloys.

Japan therefore needs new refining capacity alongside its offshore machinery. China holds most global separation capacity, particularly for medium and heavy rare earths. Building plants in Japan or partner countries takes time, and investment depends partly on lasting purchase commitments from magnet manufacturers.

Officials have discussed a small unit on Minamitorishima to carry out preliminary processing in later phases. A simple refinery near the atoll could reduce the volume that ships must carry to the mainland. Better ship scheduling, processing near the collection site and container handling could also lower transport costs.

The mud's relatively low radioactive content may make some waste handling easier, but factories would still need dependable chemistry and consistent product quality. Delivering material that meets a magnet maker's specifications is the final practical test of the supply chain.

The environmental questions beneath the surface

Deep sea mining faces opposition because ecosystems at abyssal depths remain poorly understood and can recover slowly after disturbance. Collectors and pumps can raise clouds of sediment that smother animals feeding by filtering water and alter surrounding water chemistry.

Fine particles may travel through the water column, and scientists are concerned about trace metals entering food webs. Noise from heavy equipment may also affect fish and marine mammals. Few controlled studies have examined these effects at the scale proposed for commercial mining, making their extent difficult to quantify.

Japan's staged program is intended to gather environmental information as the technology develops. Tests near Minamitorishima will map how sediment plumes move in local currents and measure how particles settle again. Engineers can adjust pump rates, collection heads and discharge locations to limit their spread.

Regulators assessing future permits will consider the size of the disturbed area, seasonal operating schedules and biodiversity monitoring. Decisions about acceptable environmental risk will develop alongside the engineering trials.

The International Seabed Authority plans to finalize a mining code for international waters. Japan's project lies within its exclusive economic zone and proceeds under domestic regulation. International standards still matter to lenders and companies considering purchase agreements, and several major banks have tightened or restricted financing for deep sea mining until environmental effects are better understood and comprehensive assessments are available.

A costly insurance policy against supply shocks

Japan is treating the project as economic and national security policy. The government wants an alternative source of critical minerals even if early production costs exceed market prices. Each offshore voyage is expected to cost more than 150 million yen.

The specialized pipe system reaching 6,000 meters and associated equipment cost on the order of tens of billions of yen, with one procurement reported at around 12 billion yen. Moving from an initial test to a pilot and then steady production would require further spending on ships, seabed machinery and plants on land.

Market prices will help determine whether those investments can support commercial production. Faster growth in magnet demand or tighter export controls could raise prices enough to support expensive offshore recovery. Falling prices would make it harder to cover costs.

Government support and purchase contracts will also matter. Refining plants require capital before they can deliver material, while manufacturers need confidence in quality and supply. Restrictions imposed by some international lenders add another financing pressure.

Officials stress patience and the value of learning every stage, from extraction to oxide, metal and magnet alloy production. The intended return is a buffer against disruption and an ability to expand as technology improves, rather than quick profit from the first voyages.

Export controls push Japan toward wider partnerships

China's April restrictions included dysprosium and terbium, which help magnets perform at high temperatures. Its October 9 expansion added further elements and intensified concern among countries dependent on Chinese processing.

Officials in Washington called the measures a direct threat to industrial supply chains. The United States signaled that additional tariffs of up to 100 percent on Chinese imports were under consideration, while allied governments urged coordinated efforts to diversify supplies and prevent further production disruptions.

Japan has accelerated coordination with the United States, India and Australia and discussed supply chain cooperation with the European Union. The discussions cover exploration, sharing data, refining and stockpiling. Their common purpose is to spread production across more regions and reduce dependence on a single supplier or processing center.

Other Pacific governments are examining seabed resources too. The Cook Islands has opened parts of its waters for exploration of nodules containing nickel, cobalt and manganese. Like Japan's project, activity inside a country's exclusive economic zone can proceed under domestic rules while the International Seabed Authority develops rules for international waters.

Buyers' willingness to accept minerals from the seabed will depend on environmental standards, the ability to trace their origin and confidence in monitoring. Japan's domestic control over its resource therefore sits alongside demands from international customers and financiers.

Recycling and different magnets are part of the same strategy

Japan's investments in Malaysia and Vietnam have helped expand refining outside China, but processing medium and heavy rare earths remains a particularly tight part of the supply chain. Minamitorishima offers a potential source of those elements if they can be separated efficiently and at the required purity.

Researchers and manufacturers are also developing magnets that use fewer rare earths or none at all. Some designs replace part of the dysprosium content or use less constrained elements, although changes can involve trade offs in magnet size or performance.

Nissan and Waseda University are developing processes to recover rare earths from motors at the end of their useful lives and from magnet scrap. Japan has also expanded strategic stockpiles and established systems to collect and reprocess valuable components from used products.

Recycling, changes in materials and stockpiling can reduce pressure on new supplies and give manufacturers more time during disruptions. They remain complementary to the effort to build mining and refining capacity outside China.

For Minamitorishima, the central challenge is joining all those industrial steps into a dependable operation. A successful trial must lead to reliable collection, manageable transport costs, effective separation and material that customers can use repeatedly at the same quality. The January 2026 test is the first planned step toward that chain, with the larger pilot scheduled for January 2027.

Key Points

• Japan plans test mining near Minamitorishima in January 2026 at depths of 5,000 to 6,000 meters.
• Researchers estimate roughly 16 million tonnes of rare earth resources, including valuable medium and heavy elements.
• A pilot planned for January 2027 would recover about 350 tonnes of mud daily, with possible private sector supply around 2028.
• Engineering challenges include a pipe reaching 6,000 meters, stable slurry transport, seabed foundations and processing capacity.
• Environmental monitoring will examine sediment plumes, settling particles and effects on deep sea ecosystems.
• Each voyage is expected to cost more than 150 million yen, while specialized equipment requires spending in the billions of yen.
• Japan has reduced its dependence on China from about 90 percent in 2010 to just under 60 percent, but remains exposed to export restrictions.
• Partnerships, refining investment, recycling, different magnet designs and stockpiles support Japan's search for more dependable supplies.