News Analysis: Japan's deep-sea rare earth mining ambition: feasible or not?

TOKYO, Feb. 6 (Xinhua) -- The Japan Agency for Marine-Earth Science and Technology announced earlier this week that Japan has recently successfully collected mud containing rare earth elements from the seabed in waters off the country's easternmost Minamitori Island.

Despite the test's success, experts remain cautious about deep-sea mining as a rare earth supply source, noting that the mission near Minamitori Island is constrained by technological hurdles, high costs and environmental concerns, with the feasibility of industrializing deep-sea rare earth elements still uncertain.

DRIVE TO EASE SUPPLY ANXIETY

Rare earth elements are widely used in renewable energy technologies, advanced materials, aerospace, electronics and defense industries. Often described as the "vitamins of industry," they are considered critical strategic resources for modern economies.

Japan has long relied almost entirely on imports for its rare earth supply, prompting efforts to diversify its sources of supply. Two Japanese firms have acquired significant stakes in Australia-based Lynas Rare Earths, though the first shipment of heavy rare earth products from Lynas mines did not reach Japan until October 2025, according to media reports.

Much of Lynas' raw material is processed in Malaysia, where export prices to Japan between 2020 and 2024 were notably higher than those of other suppliers, according to data from Japan's Mizuho Bank. While defense manufacturers may tolerate such premiums, consumer-oriented industries face tighter cost pressures.

The current exploration of deep-sea rare earth elements, which Japanese officials described as an initial step toward industrializing domestic rare-earth elements, is part of Japan's Cross-ministerial Strategic Innovation Promotion Program.

Minamitori Island lies around 1,800 km southeast of central Tokyo. A University of Tokyo research estimates that the seabed near the island contains over 16 million tonnes of rare earth resources -- theoretically enough to meet global demand for hundreds of years. The Japan Agency for Marine-Earth Science and Technology said a full-scale rare earth mud mining test could begin in February 2027.

HURDLES REMAIN

Despite decades of seabed exploration, large-scale commercial extraction of metals from the deep ocean has yet to be realized anywhere in the world. Experts warned that technological complexity and low economic returns make industrialization difficult in the near term.

Yang Fan, a researcher at the Xiamen Institute of Rare Earth Materials under the Haixi Institutes, Chinese Academy of Sciences, told Xinhua that while short-term scientific trials are feasible, long-term industrial operations would require equipment capable of withstanding extreme water pressure and severe corrosion while maintaining continuous and stable performance.

He added that energy consumption during the retrieval mission may not align with the value of the resources extracted.

Yang also pointed to challenges in processing. The composition of rare earth mud near Minamitori Island is complex, and Japan's current rare earth separation technology lags behind international advanced standards, making it difficult for its output to meet domestic demand in terms of volume, cost or quality for a considerable period of time.

Cost remains a major obstacle. Earlier estimates by Japan's Ministry of Economy, Trade and Industry suggested that, before economies of scale are achieved, extraction costs alone could reach 50 to 100 U.S. dollars per kilogram and, in some cases, exceed 150 dollars.

Besides, the research vessel for carrying out the test mission, named Chikyu, reportedly carries annual operating expenses of around 10 billion yen (about 64 million U.S. dollars), further inflating total project costs.

ENVIRONMENTAL CONCERNS

The ecological consequences of seabed rare earth mining remain largely unknown and could cause irreversible disruption to deep-sea ecosystems.

Yang noted that while the radioactivity of seabed rare earth mud is usually lower than that of terrestrial ores, the risks are not zero, and large-scale seabed disturbance could have impacts on fishery resources and marine ecosystems.

The Australian Broadcasting Corporation reported that many environmental groups and Pacific island nations have warned that seabed mining could damage marine habitats, contaminate food chains and generate large sediment plumes.

Environmental risks associated with the refining of rare earth mud have also drawn attention. Toru Okabe, a professor at the University of Tokyo, told Japanese media that there is still no clear solution for handling the large volumes of waste produced during the refining process.

Experts said the Minamitori Island project at present remains a technology demonstration rather than an industry venture with clear commercial prospects. Even if limited commercialization is attempted in the future, it would likely depend heavily on government subsidies and struggle to achieve sustainable operations through market competitiveness alone.

James Tekune, a research associate at the Netherlands-based consultancy Adamas Intelligence, remained cautious about the prospects for deep-sea mining in general as a future source of rare earths, noting it could, at best, "emerge as a niche supply stream."