Japan reveals rare earth mud composition from deep seabed off Minamitori Island

Japan has disclosed that rare-earth-rich mud from a depth of 6 km near Minamitori Island contains 54% medium and heavy elements, as the country prepares a large-scale mining trial amid escalating Chinese export controls.

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Japan has disclosed the composition of rare-earth-bearing mud recovered from the deep seabed near Minamitori Island, a step toward reducing reliance on Chinese supplies. Government analysis shows that medium and heavy rare earth elements account for approximately 54% of the total rare earth content in the samples, according to a release on July 26, 2026.

The mud was retrieved during a month-long mission by the scientific drilling vessel Chikyu in February 2026, operating about 1,900 kilometers southeast of Tokyo. The vessel achieved what project manager Kazushige Kikuchi called the world's first continuous lift of rare-earth-bearing seabed mud from a depth of roughly 6 kilometers. Around 50 metric tons of material were brought to the surface.

Among the elements identified are yttrium, gadolinium, and dysprosium, all critical for electronics, magnets, and defense applications. However, the Japanese government has not disclosed the total size of the deposits, citing limited sampling.

Japan plans a month-long large-scale mining trial in February 2027 in the same waters, targeting 350 tons of mud per day. The extracted mud will be dewatered on Minamitori Island and then sent to the mainland for testing separation, refining, and smelting technologies. "The trial is expected to verify the feasibility of domestic rare earth production," Kikuchi said.

The push for domestic supply comes as China tightens export controls. Beijing imposed restrictions on some heavy rare earths and magnets in April 2025. In January 2026, China further tightened limits on exports to Japan, with two additional rounds of restrictions that month targeting major conglomerates.