Highlights

• Japan plans a pioneering deep-sea rare earth extraction trial in January 2026.
• The trial will use the Chikyu vessel to retrieve mineral-rich mud from a depth of 5,500 meters.
• The project aims to disrupt China's near-total control of rare earth mineral supply.
• Potential implications include geopolitical and technological impacts.
• Despite promising goals, significant challenges remain in the following areas:
  • Technical challenges
  • Economic challenges
  • Environmental challenges
• The challenges must be overcome to make deep-sea rare earth extraction commercially viable.

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Japan is gearing up to launch what it calls a “world-first” deep-sea rare earth extraction trial in January 2026—an ambitious plan that could, if successful, disrupt China’s near-total dominance in rare earth refining. However, behind the headlines, Rare Earth Exchanges (REEx) raises serious questions about the feasibility, environmental risks, and long-term viability of this seabed mining venture.

According to a report (opens in a new tab) from Channel News Asia, the project will involve the Chikyu, Japan’s state-of-the-art deep-sea scientific drilling vessel, retrieving rare earth element (REE)-laden mud from a depth of 5,500 meters off Minami Torishima, a remote Pacific island within Japan’s Exclusive Economic Zone (EEZ). Officials from Japan’s Cross-ministerial Strategic Innovation Promotion Programme (SIP) confirmed that the mission will extract up to 35 tonnes of sediment over three weeks, not for commercial gain but to test full equipment functionality in extreme underwater conditions.

Each tonne of sediment is expected to yield just 2 kg of rare earths—mostly in the form of magnetic elements like neodymium and dysprosium. But even this modest estimate raises fundamental questions. Can a process that retrieves only a few kilos of metal per tonne of wet, gritty mud—at miles below the ocean surface—ever become commercially viable? Or is this yet another taxpayer-funded techno-nationalist moonshot with more PR value than real-world promise?

The article accurately notes China’s overwhelming grip on the REE supply chain, with over 60% of mining and 92% of global refining, according to the International Energy Agency. It also references Japan’s Quad partnership with the U.S., India, and Australia to diversify supply sources. But there’s a certain gloss over the complexity of what’s being attempted.

Let’s be clear: deep-sea mining at this depth is not new in concept, just in Japanese REE-specific applications. Countries like France, Korea, and China have long trialed the retrieval of nodules and mud from similar depths, often with mixed results and high costs. What makes Japan’s move unique is its focus on REE-bearing mud rather than polymetallic nodules and its intention to build a seabed-to-magnet domestic value chain.

Serious Questions

Yet major gaps remain in the coverage. For one, the article only gives a fleeting nod to environmental concerns despite widespread warnings from marine scientists about irreversible damage to deep-ocean ecosystems. And while the Chikyu is a marvel of engineering, extracting, lifting, processing, and separating valuable metals from seabed silt is a thermodynamic and economic nightmare—especially when compared to land-based projects.

CNA’s piece also misses the opportunity to ask: who’s funding this long-shot experiment? What Japanese companies or agencies are involved? And how does this strategy compete with ongoing efforts in REE recycling, solvent-free separation, or U.S.-led monazite reprocessing?

If Japan succeeds, it could open a new frontier in resource security. But success here should not be measured in tonnes of mud lifted—it must be judged on cost, scalability, and sustainability. Until then, we’re watching a nation dive deep into uncharted waters—technologically, financially, and literally.

What’s the Feasibility

Deep-sea mining of rare earth elements presents formidable technical, economic, and environmental challenges. Extracting mineral-rich mud or nodules from depths exceeding 5,000 meters requires specialized equipment capable of withstanding crushing pressures and operating in pitch-black, high-current environments. Even if sediment is successfully retrieved, separating trace amounts of valuable rare earths from vast volumes of waterlogged material remains energy-intensive and chemically complex.

The costs of lifting, drying, transporting, and refining seabed mud are steep—and currently uneconomical without major subsidies or breakthroughs in extraction efficiency. Furthermore, environmental concerns are significant: deep-ocean ecosystems are poorly understood, and mining operations risk irreparably damaging fragile habitats, disrupting sediment layers, and introducing pollutants into pristine marine environments. Regulatory uncertainty, especially in international waters, further complicates investment and deployment.

Rare Earth Exchanges™ Bias & Depth Meter

Category	Score (0–10)
Accuracy of Factual Claims	9
Depth of Technical Analysis	4
Disclosure of Economic Realities	3
Geopolitical Context & Balance	6
Stakeholder Transparency	2
Environmental Risk Acknowledgment	3
Hype vs. Reality Framing	4

Total Score: 31/70 – Moderately Shallow, Technically Sound But Critically Underdeveloped—Investor Caution