JAMSTEC's research vessel Chikyu.
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The Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has successfully carried out test drilling off Minamitorishima Island (Ogasawara Village, Tokyo), within Japan's exclusive economic zone (EEZ). The team recovered mud containing rare earths under the seafloor at a depth of about 5,700 meters.
Rare earths are essential for high-tech products. However, Japan has no commercial rare-earth mines, which has left it heavily dependent on overseas supply, especially from China, creating an economic security vulnerability. Against that backdrop, the successful test is being seen as an important step toward building a domestic supply.
Confidence in Large-scale Extraction
The rare-earth mud off Minamitorishima was selected for Japan's Cross-ministerial Strategic Innovation Promotion Program (SIP), which aims to commercialize it as a seabed mineral resource. A large-scale extraction demonstration is planned for February 2027, and the test drilling marked a key milestone in determining whether the project is ready to proceed.
SIP Program Director Shoichi Ishii called it a "world-first challenge." He said the team succeeded in "continuously lifting solid material from a depth of 5,700 meters," and that the achievement gave them "the confidence to take on large-scale extraction next year (2027)," he told the Sankei Shimbun.
In the test drilling, engineers lowered a special double-structure pipe from the deep-earth exploration vessel Chikyu and drove the tip into the seafloor. A propeller at the tip stirred the mud and seawater into a slurry that was easier to collect. Water was then pumped from the ship down the inner pipe, and water pressure was used to lift the slurry back up to the vessel through the outer pipe.
Operations were carried out with support from an ROV (remotely operated vehicle), which opened and closed valves at the pipe tip and helped monitor conditions. A deep-sea probe called Edokko 1 tracked possible environmental effects, including impacts on the ecosystem, seawater turbidity, and the generation of sound.
Strategic Stakes and the Problem of Refining
Rare earths are used across a wide range of products, including electric vehicle motors, camera lenses, and LED lighting. Because even small amounts can sharply improve performance, they are sometimes called the "vitamins of industry."
The geopolitical risk is that supply chains are concentrated. China accounts for 91% of the world's refined rare earths. In the past, it has used export restrictions and other pressure when geopolitical tensions rise, effectively treating rare earths as a diplomatic "card." The test-drilling success, therefore, carries major economic security significance, as it increases the likelihood that Japan could secure a supply from within its own EEZ.
Another issue is environmental cost. Rare earth ore mined on land often contains radioactive materials such as thorium and uranium, making refining a pollution-control challenge. In Europe and the United States, where environmental regulations are strict, compliance costs have contributed to downsizing or withdrawal from refining projects.
China, by contrast, came to shoulder refining by taking advantage of looser regulations and lower labor costs. However, the environmental destruction and health impacts associated with refining have become domestic social problems.
By comparison, the mud lifted from off Minamitorishima, which contains rare earths at high concentrations, is said to contain almost no radioactive materials. Some estimates suggest the reserves could cover "several hundred years of global demand." Observers have also noted the presence of especially scarce types. Together, these points have raised expectations that Japan could secure high-quality strategic resources while keeping countermeasure costs down.
Reserves on a National Scale
The rare-earths mud off Minamitorishima was discovered in 2012 by a research team led by Professor Yasuhiro Kato of the University of Tokyo. Surveys at the time estimated reserves of about 6.8 million tons, equivalent to roughly 230 years of Japan's domestic consumption.
Analyzed by element, the team estimated about 400 years' worth of dysprosium, which is essential for EV motors and an area where Japan's dependence on China is especially high. It also estimated about 4,600 years' worth of terbium, used for magneto-optical disks. They hailed it as a 'dream deposit' within Japan's EEZ.
Fourteen years later, Kato welcomed the latest test drilling as "a major step toward developing it as a rare-earth deposit." He added, "What matters most is whether it can ultimately be commercialized, and I want to encourage the efforts forward."
Looking ahead to commercialization, the biggest challenge will be cost-effectiveness. Ishii said that next year's large-scale extraction demonstration will be used to gather more detailed data, and that SIP will "compile an economic evaluation and other assessments by March 2028."
A Historic First Step
Mariko Mabuchi, representative director of the Japan Institute of Finance and Economics, described the Minamitorishima test as "a historic first step" in shifting Japan's economic security. She said the significance lies in the technical feat of lifting material from a depth of nearly 6,000 meters, and in what it represents as Japan works to reduce its reliance on China for strategic resources.
Mabuchi noted that Japan imports 66% of its rare earths from China and argued that Japan should build a domestic self-sufficiency system as quickly as possible. Verification will now move toward production volume and the costs of recovery and processing for full commercial extraction. Even if costs prove high, she suggested Japan is unlikely to abandon extraction.
Global demand is rising for resources used in advanced industries such as AI and semiconductors, Mabuchi said. In that environment, she argued, Japan can create value through domestic self-sufficiency. She also pointed to exports as a potential path. Japan could "export to friendly countries" and generate profits, she said, an approach that could help Japan "emerge as a resource powerhouse."
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(Read the article in Japanese.)
Author: Juichiro Ito, Hikaru Ichinosawa, The Sankei Shimbun
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