Japan deep seabed rare-earth mud test: system design and impacts for miners
Reviewed by Joe Ashwell
First reported on MINING.com
30 Second Briefing
Japan will run a month-long pilot from 11 January to 14 February to continuously lift rare-earth-rich mud from about 6,000 m depth near Minamitorishima Island, targeting 350 t/day via a full integrated deep-sea mining system 1,900 km southeast of Tokyo. The Japan Agency for Marine-Earth Science and Technology will monitor environmental impacts both on the seabed and onboard while operating within Japan’s exclusive economic zone. Dewatering will occur on Minamitorishima using spin-dryer-style equipment to cut mud volume by roughly 80% before shipment to mainland refineries, following ¥40 billion of government funding since 2018.
Technical Brief
- Strategic Innovation Promotion Program is directing the work, targeting a domestically controlled rare earths supply chain.
- No formal production target or resource tonnage has been disclosed, limiting current economic feasibility assessments.
- Dewatered concentrate will still require transport from Minamitorishima to mainland Japan for separation and refining.
- Government funding totals about ¥40 billion since 2018, covering exploration, system development and pilot operations.
- The test area lies within Japan’s exclusive economic zone, simplifying permitting but sharpening geopolitical sensitivities.
Our Take
The Japan rare earths push around Minamitorishima sits alongside other non-Chinese supply strategies in our database, such as Iluka Resources’ and Lynas Rare Earths’ projects highlighted in the Wood Mackenzie–centred piece from 11 December 2025, signalling a multi-continent effort to dilute China’s dominance in refined rare earths.
A government-funded spend of about ¥40 billion since 2018 on seabed mud extraction suggests Japan is treating this as strategic infrastructure rather than a pure R&D exercise, which could give downstream Japanese magnet and electronics manufacturers more leverage in long-term offtake negotiations referenced in broader critical minerals coverage.
Testing the ability to handle 350 t/d of deep-sea mud with an 80% volume reduction is technically significant because it directly addresses one of the main bottlenecks flagged in other rare earths projects in our coverage: the cost and logistics of moving and processing very low-grade, high-mass feedstocks at scale.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
Related Articles
Related Industries & Products
Mining
Geotechnical software solutions for mining operations including CMRR analysis, hydrogeological testing, and data management.
Construction
Quality control software for construction companies with material testing, batch tracking, and compliance management.
CMRR-io
Streamline coal mine roof stability assessments with our cloud-based CMRR software featuring automated calculations, multi-scenario analysis, and collaborative workflows.
HYDROGEO-io
Comprehensive hydrogeological testing platform for managing, analysing, and reporting on packer tests, lugeon values, and hydraulic conductivity assessments.
GEODB-io
Centralised geotechnical data management solution for storing, accessing, and analysing all your site investigation and material testing data.