Manganese Nodules: The Ocean Resource Not Yet Profitable to Mine
Manganese nodules (polymetallic nodules) are the poster child for "resources that exist but aren't economic."
What They Are
- Potato-sized (2–10 cm) concretions on abyssal plains (4,000–6,000 m depth)
- Composition: Mn (24%), Fe (14%), Ni (1.3%), Cu (1.1%), Co (0.25%), + REEs, Mo, Li, Te
- Growth: 1–10 mm / million years (slowest geological process)
- Clarion-Clipperton Zone (CCZ, Pacific): 21B tonnes estimated — largest deposit
Why Not Profitable (Yet)
| Barrier | Details |
|---|
| Depth | 4–6 km → extreme pressure, cold, darkness; requires ROVs/AUVs, not divers |
| Lift Cost | Riser pipe 4+ km, pump slurry, dewater — energy intensive |
| Processing | Complex metallurgy (Cu-Ni-Co-Mn separation); no commercial plant exists |
| Capital | $10–20B for first commercial system (nodule collector, riser, ship, plant) |
| Metal Prices | Volatile; Ni, Co, Cu must stay high for years to justify CapEx |
| Regulation | ISA (International Seabed Authority) — Mining Code not finalized; sponsorship state liability |
| Environment | Sediment plumes, biodiversity loss (nodule fauna), noise, light — unknown recovery times |
| Social License | NGOs, Pacific nations, BMW, Volvo, Google, Samsung pledge moratorium |
Competitors: Other Seabed Resources
- Cobalt-rich crusts (seamounts) — thinner, harder to mine
- Seafloor massive sulfides (SMS) (hydrothermal vents) — higher grade, smaller, active ecosystems
- Rare earth muds (Pacific) — REE-rich, but diluted
Timeline
- 2024–2025: ISA Mining Code adoption decision
- 2026+: First test mining (The Metals Co / Nauru; GSR / Belgium; China Minmetals / COMRA)
- 2030s?: Commercial if economics + regulation align
Verdict
Manganese nodules are a strategic reserve, not a current reserve. Land-based mining (Indonesia Ni, DRC Co, Chile Cu) and recycling (EV batteries) currently outcompete. Deep-sea mining remains "10 years away" — as it has since the 1970s.
Wanderlust World