The Australian TV science magazine show, Catalyst, screened a segment on deep-sea mining Thursday evening (AEST), with a special focus on the Solwara 1 deep-sea mine in Papua New Guinea.
You can read the transcript below or watch the video HERE
Most volcanic activity happens not on land, but kilometres down in the deep ocean. Geological research has revealed that underwater volcanoes, or hydrothermal vents, are rich in metals like copper, zinc, silver and gold at concentrations that make them commercially attractive to miners. But, they are also colonised by exotic life-forms and scientists believe the vents may have been the location where life originated. Mark Horstman takes a look at a mining project that is set to commence operations in the deep waters off Papua New Guinea.
NARRATION
You may not get to see an eruption very often, but we live on a volcanic planet where they happen all the time. Most volcanic activity happens not on land but kilometres underwater in the deep ocean covering two thirds of the earth’s surface. Wow! Holy Moly. This is a story about volcanic hot springs called hydrothermal vents. Told by two explorers from different scientific view points. One a geologist.
Dr Chris Yeats
There’s ones about dinosaurs and ones are live volcanos. And I’m one of the volcano loving ones. So it was, it’s great for me.
NARRATION
And the other a biologist.
Professor Cindy Lee Van Dover
The roots of, of the tree of life as we know it right now, the deepest roots we know of come from hot springs.
NARRATION
And both have undertaken research in deep sea vents with a daring plan to mine them. In 1990 Cindy Lee Van Dover became the first woman to pilot the US submersible ALVIN. Routinely diving to depths greater than two thousand metres she’s explored nearly all of the world’s hydrothermal vent fields. Chains of them occur along fault lines, like the Pacific Rim of Fire and the Mid Atlantic Ridge.
Professor Cindy Lee Van Dover
Even after a hundred dives, like I’ve made, there’s a sense of anticipation of not knowing what you’re going to see when the flood lights come on.
NARRATION
Here’s how hydrothermal vents work. Under incredible pressure sea water pushes into fractures, is rapidly heated, picks up chemicals as it reacts with the hot rock and gushes out of the sea floor at scalding temperatures. What was once plain sea water is now hydrothermal vent fluid.
Professor Cindy Lee Van Dover
What’s special about these environments is that it’s this wonderful mixture of vent fluid and cold sea water with chemicals that microbes can use to make new organic material. So it sets up a food web. And once you have that food web set up then species can come in and use it.
NARRATION
This dark, toxic unstable environment supports an amazing array of bacteria, snails, muscles and crabs. In the Eastern Pacific giant tube worms grow to two metres in just a couple of years.
Professor Cindy Lee Van Dover
They have no mouth, they have no gut – how do they make a living? This is a giant animal on the sea floor. Where is, where is it getting its nutrition. And the answer is that they have bacteria that live inside of them.
NARRATION
With their symbiotic microbes the animals crowding around deep sea vents aren’t the only ones seeking out plumes of sulphide minerals. So do geologist.
Dr Chris Yeats
That’s a really, really nice black smoker. And that’s, yeah that’s about as black as you get.
Mark Horstman
How big would something like this be?
Dr Chris Yeats
Oh that’s probably one and a half to two metres in height.
NARRATION
But they come a lot bigger than that.
Dr Chris Yeats
That’s enormous. That’s absolutely enormous.
NARRATION
That’s Chris Yeats you can hear in the submersible at a depth of more than sixteen hundred metres exploring a vent field and collecting samples of chimneys, like this one.
Dr Chris Yeats
This central cavity here would have been full of very hot water. Um, you’re talking about stuff which is two hundred and fifty or three hundred degrees centigrade. And pumping very rapidly, it, it may well have been a black smoker with black smoke coming out of the top of it. And you sort of get a very sharp temperature grade in between, three hundred degrees here, and three degrees out here.
NARRATION
As the hot acidic chemical laden fluid hits the cold sea water the metal sulphides drop out a solution to grow a chimney. But when the fluids are really hot to form a huge plume of particles that looks like black smoke.
Professor Cindy Lee Van Dover
You come on a black smoker and it’s like being in an industrial landscape. They can be really quite tall structures in some places, thirty metres tall.
Dr Chris Yeats
You’re sitting on the side of an active volcano, there’s this constant earthquake, these structures are quite fragile. They’re constantly changing and evolving. Collapsing, starting, finishing.
NARRATION
To biologists the discovery of more than five hundred previously unknown species living on deep sea vents makes them cradles of biodiversity.
Professor Cindy Lee Van Dover
I could take you tomorrow to a place where we’d find a new hydrothermal vent that would almost certainly have dozens, if not hundreds of new species.
NARRATION
To geologists vent fields are the birth place of giant ore bodies with grades of copper and zinc many times higher than those found on land. And that’s got the attention of mining companies.
Dr Chris Yeats
This is the Bigpela Chimney, it’s the biggest chimney ever dredged on the sea floor, and I’m sitting down near the base here and, and the fluid would have been gushing up from the bottom towards the top.
Mark Horstman
So it’s extinct now? That’s why it’s all filled in, but it’s full of minerals like gold, silver, zinc. Is it worth mining?
Dr Chris Yeats
Oh certainly worth mining.
NARRATION
This chimney comes from a vast hydrothermal vent field deep in volcanically active Bismarck Sea off Papua New Guinea. And it’s here that a company called Nautilus Minerals is planning Solwara One, the world’s first open cut mine for copper and gold on the sea floor.
Dr Chris Yeats
The amount of metal value you gain from, from mining something like Solwara One is the kind of metal you’d gain from mining something ten or fifteen times the size on land. So potentially they’re a very efficient way of mining.
NARRATION
Here’s the plan. On the sea floor at one point six kilometres deep three remote control robotic miners crush the chimneys and grind up the sulphide deposits, which along with everything living on them are sucked up by a giant vacuum cleaner to a ship on the surface. The slurry is filtered and the waste sent back down the pipe to the seabed where it’s released. Over a period of eighteen months two million tonnes of ore would be mined from the vent field and shipped to nearby Rabaul.
Mark Horstman
During the time I was making this story Nautilus Minerals declined my invitation for an interview and announced a joint venture with the PNG Government to start mining within the next few years.
Dr Chris Yeats
The activities that Nautilus are proposing are something like ploughing a field or raking your garden, that you’re, you’re, you’re stirring up the environment but you’re not fundamentally changing it.
Professor Cindy Lee Van Dover
We don’t know when you scrape away five thousand years of deposit, what influence did that five thousand years of deposit have on the fluid chemistry and the kinds of animals that might be able to colonise it.
NARRATION
After mining it’s likely that vent structures will reform and animals will recolonise. But the question is, how long does it take?
Professor Cindy Lee Van Dover
What interests us as scientists is that here’s a question we just don’t know the answer to. And if mining, if extraction of metal, metals on the seabed takes place we’d like to know what happens and how quickly the animals come back.
NARRATION
If Nautilus Minerals is successful it could spark a gold rush of sea floor mining in International Waters without knowing how to restore the habitats after mining.
Professor Cindy Lee Van Dover
There’s nobody who’s an expert in that. No expert exists right now who has any idea how to tackle that. I’d love to know that a hundred years from now people would look back and say, ‘That’s the generation that got it right’.
Papua New Guinea Mine Watch 