OFF THE COAST OF NAMIBIA — Deep beneath this frigid stretch of the Atlantic Ocean, some of the world’s most valuable diamonds are scattered like lost change.
The discovery of such gems has sparked a revolution in one of the world’s most storied industries, sending mining companies on a race for 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 swaths of southern Africa producing billions of dollars of wealth. But those mines are gradually being exhausted. Experts predict that the output of existing onshore mines will decline by around 2 percent annually in coming years. By 2050, production might cease.
Now, some of the first “floating mines” could offer hope for the world’s most mythologized gemstone, and extend a lifeline to countries like Namibia whose economies depend on diamonds. Last year, mining companies extracted $600 million 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,” said Bruce Cleaver, the chief executive of De Beers, in an interview.
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, 300-foot-long ships with helicopter landing platforms, dredging equipment and industrial metal pilings. On a recent day, a family of seals swam off one of them, as the machines hummed and sediment was sucked on board through a 170-yard hose to be sorted. It might be the world’s most complex commercial mining endeavor.
Diamonds are formed when carbon is subjected to high temperatures and pressure deep underground. Some were hurled toward the surface millions of years ago in volcanic eruptions. In recent decades, geologists realized 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.
De Beers, which historically dominated global diamond production, purchased mining rights to more than 3,000 square miles of the Namibian seafloor in 1991. So far, it has explored only 3 percent of that area.
The technology to extract the underwater diamonds took years to develop.
