Ocean yields precious diamonds
Gem companies hunt for riches on the seafloor
Off the coast of Namibia, deep beneath t he Atlantic Ocean, some of the world’s most valuable diamonds are scattered like lost change. The discovery of such gems has sent mining companies on a race for the precious stones buried just under the seafloor.
For over a century, open-pit diamond mines have been some of the most valuable real estate on Earth, with small areas of southern Africa producing billions of dollars of wealth. But experts predict that the output of existing onshore mines will decline by around 2 per cent annually in coming years. By 2050, production might cease.
Now, some of the first “floating mines” could offer hope for the world’s most mythologised gemstone. Last year, mining companies extracted US$600 million ($825m) worth of diamonds off the Namibian coast, sucking them up in giant vacuum-like hoses.
“As [Namibia’s] land-based mines enter their twilight years, it’s very important for us and for Namibia that we have long-term mining prospects,” says Bruce Cleaver, the chief executive of De Beers.
But as companies weigh the prospect of more offshore operations, environmentalists have raised concerns about the damage that could be inflicted on the seafloor.
From above, the mining vessels look like oil rigs, 90m-long ships with helicopter landing platforms and dredging equipment.
In recent decades, geologists realised that because diamonds could be found in Namibia’s Orange River, there was a good chance they could also be detected at sea, swept there by the current. As it turned out, the underwater gems were among the world’s most valuable stones — with far greater clarity than diamonds mined on land.
The technology to extract the underwater diamonds took years to develop. Only recently has De Beers been able to efficiently scavenge the sea for diamonds. Underwater gems only represent about 13 per cent of the value of diamonds De Beers mines onshore each year, but more countries are pushing for exploration to begin along their coastlines.
Last year, the world spent US$80 billion on diamond jewellery, more than half of it in the United States, an all-time high. Demand in emerging economies such as China and India is also expected to increase.
Diminishing supply and that rising demand have made Namibia’s offshore deposits all the more important. In the 1990s, De Beers sent its first commercial vessels into the Atlantic in search of diamonds.
These days, the company uses drones to fly over vast stretches of the ocean, looking for areas that might be worth exploring. Then it sends vessels to dredge the most promising areas. Most diamonds are close to the surface, De Beers says, so it does not go deeper than 2m beneath the seafloor.
A remote control, tractor-like crawler moves slowly along the seafloor, directing a hose that sucks up tonnes of sediment every hour.
The sediment is then passed through a series of machines that cull material first by size and then, using X-ray technology, by geological composition. Diamonds make their way down five floors of conveyor belts and machines into a metal container that looks like a soup can.
Diamond mining contributes roughly a tenth of Namibia’s gross domestic product, and its offshore contract with De Beers is a 50-50 partnership with the government. But while the soaring revenue has made some Namibians rich, this remains the world’s third most unequal country, according to the World Bank.
Although Namibia is considered the easiest place to extract offshore diamonds, mining executives are not ruling out exploring other stretches of ocean. Marine mining has also taken place off the coast of South Africa, though it has proven less lucrative.
But environmental groups have raised concerns about the offshore mining operations, which spew the sediment back into the ocean after it is processed for diamonds. Companies also plan to begin mining offshore for gold in coming years, with one commercial operation scheduled to launch next year off Papua New Guinea.
“My concern with this and all deep-sea mining is that we just don’t know much about the deep sea at all,” says Emily Jeffers, a lawyer with the Centre for Biological Diversity, a US nonprofit organisation. “The worry is that we are going to irreparably harm this environment and these species before we discover them.”
De Beers says its offshore operations do not cause significant ecological damage, as the sediment eventually resettles.
The company says it employs ecologists who monitor the environment where they have mined to make sure it is recovering.
Sitting on the bridge of the diamond ship Mafuta one recent day, a middle-aged South African man named Leonard Bunce manned the joysticks that control the dredging equipment. In front of him, screens showed a live stream of various stages in the mining process. Sometimes, he says, he sees fish and octopus sucked up by the hose, but they appear to survive as they are dumped back into the sea.
Mostly, what Bunce saw that day were the tonnes of sediment churned into the vessel — any diamonds indistinguishable on his screen. The culling process is entirely mechanised, and the diamonds are only visible to workers when they are dropped into the can. When enough of the gems accumulate there, the can is sealed and flown to Windhoek, Namibia’s capital.
That is where, in an office in a nondescript building, Peter Kayser inspects high-value diamonds that could be worth anywhere from tens of thousands to millions of dollars.
One day last month, his attention was on a diamond about the size of the tip of his thumb that had recently been vacuumed up from the ocean floor. He passed the gem through a machine that calculated its weight and a number flashed on a screen: at least seven carats.
Kayser smiled. “This could be a very expensive stone.”
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