What’s inside a nodule, and why the world wants it.
Deep-sea mining is the collection of mineral resources from the deep ocean floor — typically at 4,000 to 6,000 metres depth. The primary target is polymetallic nodules: potato-sized formations rich in high-value critical minerals. The key minerals are manganese, nickel, copper, cobalt and rare earth elements, all of which are vital for clean-energy technologies, electronics, medical devices and national defense.
Worth knowing: no commercial nodule mining is occurring anywhere in the world today. Every project, everywhere, is still at the exploration or testing stage.
Concentric layers of metal, built one micron at a time.
Cut a nodule open and you see rings, like a tree. Each ring is metal oxide that precipitated out of seawater and pore water around a tiny nucleus. The valuable metals concentrate in a band just under the surface.
- MnManganese
- FeIron
- NiNickel
- CuCopper
- CoCobalt
- REERare earth elements
- Growth rate≈ 1 mmper million years — among the slowest geological processes known
- Where they sitLooseon the sediment surface of abyssal plains, not embedded in rock
- SizePea → potatofrom a few millimetres to a large potato
Five metals, and where they end up.
- MnManganeseBatteries & steel production
- NiNickelElectric-vehicle batteries & stainless steel
- CuCopperElectronics, wiring & renewable energy
- CoCobaltHigh-performance batteries & defense systems
- REERare Earth ElementsAdvanced electronics, magnets, medical devices & clean-energy tech
“One small nodule contains the key ingredients for the technologies that power our modern world.”
These minerals are already part of everyday life.
Today they come mostly from land-based mines. The question is not whether we use them — we already do — but where the next decades of supply should come from.
Smartphones
Copper, nickel, cobalt, manganese
Laptops & electronics
Copper, nickel, cobalt
Cars
Manganese & nickel in steel; copper in electrical systems
Rechargeable batteries
Nickel, manganese & cobalt in some lithium-ion batteries
Homes & appliances
Copper wiring, motors & stainless steel
Power grid
Large amounts of copper
Medical technology
Specialty metals & rare earth elements
Aircraft & defense systems
Nickel/cobalt alloys & other critical minerals
Demand is rising across five sectors at once.
- 01
Smartphones & electronics
Compact, high-performance devices we rely on daily.
- 02
Defense systems
Advanced weaponry, communications, and national security.
- 03
Medical equipment
MRI machines, pacemakers, surgical tools.
- 04
Renewable energy
Wind turbines, solar panels, battery storage.
- 05
Modern infrastructure
Transportation, power grids, digital connectivity.
Global demand for these metals is rising, and every source has trade-offs. Whether the deep sea should be one of those sources — and whether American Samoa’s waters should be part of it — is exactly the open question this site exists to explore. Weigh the environmental questions alongside the potential benefits and risks.
From the abyssal plain to a ship: the basic idea.
Because nodules lie loose on the sediment, the concept is closer to harvesting than to digging: a collector gathers nodules from the seafloor, they are lifted to a production vessel at the surface, and the ore is transferred to a carrier for transport to shore. How the first two steps are done is the part still being worked out — switch between the two designs below.
Collector design
Nothing at commercial scale
Newer concepts hover above the seabed and lift nodules with a flow of water rather than scraping, then raise them in a sealed container instead of pumping a sediment slurry up an open riser. Every part of this is still being developed and tested — no system is collecting nodules commercially anywhere in the world.
This is a concept diagram, not a photograph of any real system, and no system of either kind is collecting nodules commercially anywhere in the world. See Technology for how older designs differ from the newer ones being tested, and The process for why none of this is happening in American Samoa today — and the steps that would have to come first.