Why the next gold rush is happening at the bottom of the ocean
PRIMER
Down past the jellyfish, through the water column and beyond the light is the deep sea: the place between 200 to 11,000m (650 to 36,000ft) below the ocean’s surface. The extremely high pressures and cold, dark conditions make unique habitats for the surprisingly colourful life here – bizarre creatures like hairy-chested crabs and glittery Elvis worms.
But some people have their eyes on a different sort of riches formed in these unusual conditions: rare earth metals. Dr Helen Scales explains the drive to mine the materials buried in the deepest parts of the ocean.
THE WORD ‘MINING’ USUALLY BRINGS UP IMAGES OF GRUBBY FACES IN HARD HATS DISAPPEARING UNDERGROUND. SO WHAT IS MINING WHEN IT’S IN THE DEEP SEA?
It’s just as grubby as mining on land – the difference is there aren’t people actually in deep-sea mines. It’s all going to be done remotely, using similar sorts of camera and robot technologies to those scientists are using to explore the deep sea. Only they’ll be much bigger, with mining machinery bolted to them.
There are three main mining targets: polymetallic nodules, seamount crusts and hydrothermal vents.
For mining nodules – these dense lumps of rare metals – imagine a massive digger with caterpillar treads and, on the front, a massive scoop. That scoop is going to stick forks into the seabed and then drag them forwards, pick up the rocks and pop them into a tube – a huge pipe that’s several miles long and will suck those rocks up to the surface.
One of the other places people want to mine is seamounts – those enormous mountains covered in metal-rich crusts. To mine these and hydrothermal vents, it’ll be the same big digger with caterpillar treads, but with a big mining drill head. One thing that’s not yet truly apparent is the scale on which this mining is going to happen.
WHAT ARE POLYMETALLIC NODULES?
They look like lumps of coal, or black potatoes. They’re very dense as they’re full of metals, so they’re incredibly heavy for their size – and they’re actually radioactive.
The way they form is fascinating – they basically form from the water itself. It begins with a little fragment of something, such as a shark tooth or a piece of whalebone lying on the seabed. Then over the eons, dissolved minerals and metals in the seawater
