Japan's deep-sea mud sample yields heavy rare earths, paving way for 2027 mining trial

Japan's seabed sample analysis

Japan's government reported on Friday that an analysis of rare earth-rich mud retrieved from the deep seabed near Minamitorishima island, about 1,900 kilometers southeast of Tokyo, found that medium and heavy rare earth elements accounted for about 54% of the total rare earth content. The Japanese scientific drilling vessel Chikyu completed a monthlong mission in February near the remote Pacific island, marking what officials described as the world's first successful attempt to continuously lift rare-earth-bearing seabed mud from depths of around 6 km. Officials did not disclose the overall size of the deposits, citing insufficient data from the limited duration and geographic scope of sampling.

Elements identified and scale of recovery

About 50 metric tons of mud were recovered during the mission. According to the Cabinet Office's national platform for innovative ocean development, the analysis identified yttrium, used in aerospace, energy and semiconductor applications; gadolinium, used in magnetic resonance imaging and other high-tech applications; and dysprosium, used in high-performance magnets for electric vehicles. The identification of these elements aligns with Japan's strategic interest in diversifying supplies of materials used in defense, automotive, and clean-energy technologies.

Planned 2027 large-scale mining trial

Japan plans a monthlong large-scale mining trial in the same waters from February 2027, aiming to dredge 350 tons of mud a day. The material will be dewatered at Minamitorishima island and processed on the mainland to test separation, refining, and smelting technologies. Kazushige Kikuchi, project manager at the Japan Agency for Marine-Earth Science and Technology, which operates the Chikyu, said the trial is expected to verify the feasibility of domestic rare earth production, with a comprehensive assessment of industrialization prospects due by March 2028.

Context of Chinese export controls

The Japanese project comes amid tightening Chinese export controls on heavy rare earths and related magnets. Beijing imposed export controls on some heavy rare earths and related magnets in April 2025 and tightened restrictions on exports to Japan in January, and twice again the following month, targeting major conglomerates. The controls have heightened concerns in Japan about supply security for materials critical to defense and automotive industries.

Sweden draws attention as alternative source

ScienceDaily published coverage on Friday headlined "Sweden's hidden rare earth deposits could help break China's grip," highlighting growing European interest in diversifying critical mineral supply. Full details of the Swedish assessment were not available in the supplied evidence, but the headline indicates increasing attention to non-Chinese rare earth sources as Beijing tightens its export regime.