Moment We Found a 1,098-ct DiamondJuly 01, 21
There were three people present when the seal was broken on a "diamond over-size collection bin" at Jwaneng mine, Botswana - revealing by far the biggest diamond they'd ever seen. Three people and some excited screaming.
This was the moment, on 1 June 2021, when an otherwise ordinary working day became anything but ordinary.
Two plant operators and their security escort had just become the first people to set eyes on a rough stone from the mine's South Kimberlite Pipe, that was later measured at 73mm x 52mm x 27mm.
Within 12 hours it had been validated as a genuine diamond - rather than any other mineral - and weighed at 1,098.3 carats. It became, subject to confirmation, the third largest gem quality diamond ever recovered in the world.
There was no clue until they opened the diamond over-size collection bin, that such a huge stone was lurking within. Ore blasting from the pit is taken to the primary crusher in a routine and automated process. They're broken into pieces of less than 150mm, then sent to scrubbing to remove clay-rich material around the kimberlite.
They're taken to a gravity separation process (dense media separation) based on density. And from there they're sorted by size into different collection bins, and it's only when the bins are unsealed by the security escort that it becomes clear what's inside.
"The security guy breaks the seal once it's full," said Edwin Elias, head of ore processing at Debswana Mining Company, jointly owned by De Beers and the Botswana government.
"One of the operators looked inside and saw something that was way bigger than he expected. He screamed to the other guy and they called the plant supervisor.
"When you recover a stone of this magnitude the excitement is amazing. The first thing is that you look at its size and then you ask 'is this real?'
"It's an historic moment. I've been in the business for 20 years and I've never held a stone of that size. We've never recovered a diamond of this magnitude, during more than 50 years of our mining.
There's always a risk that such an enormous stone will be broken into smaller pieces as it passes through the various crushers, but Elias says there's been a huge investment in technology since the mine went into full production in 1982.
"We've invested fully to be able to recover stones of this magnitude. This demonstrates that we have the machinery to do it and we have the skills and capacity to do it."
Debswana have been celebrating the recovery but Elias said: "We will celebrate more when we know the valuation of this stone."
The stone is expected to be valued next week by the Diamond Trading Co. Botswana. The decision will then be taken as to whether it is sold by De Beers, which owns 50 per cent of Debswana, or through the state-owned Okavango Diamond Co.
For context the 1,111-ct Lesedi La Rona, recovered in 2015 by Lucara at its Karowe mine, also in Botswana, sold for $53m. It was bought by the British jeweler Graff.