Modern Mining May 2023

Venetia’s open pits bow out in style

Three decades of continuous open pit mining at De Beers’ Venetia diamond mine came to an end in December 2022 when the last load of ore was hauled out of the K1 pit. A total of three open pits were mined over the life of the mine. According to Venetia’s outgoing Gen eral Manager, Gerrie Nortje, the open pit operation ended on a strong note, with the main pit, K1 working so efficiently in 2021 and 2022 that carat production was at near-record levels during these years. Modern Mining recently spoke to Nortje about the highlights of his tenure as GM.

T he ore from the open pits will ultimately be fully replaced by ore from the US$2 billion Venetia Underground Project (VUP), which will com mence production in 2023. The VUP’s ramp-up will be complete around 2026, at which point the mine will be producing at a rate in excess of 5 mt/a (with up to 5.9 mt/a expected at peak). According to Nortje, Venetia will rely on stock piles to bridge the short gap between the end of open pit production and the start of the VUP. “This stockpiled material will be fed to the plant for the next few years,” he explains. “In parallel, the VUP

will be producing ever increasing tonnages of ore month by month as it ramps up. Inevitably, there will be some impact on carat production in the short term but this was always expected and, fortunately, was partially offset by the excellent results achieved in 2021 and 2022.” Elaborating, he says Venetia produced 5.3 mil lion carats (mct) in 2021 and 5.5 mct in 2022. “These were the best figures since 2008 and significantly higher than the annual average of 4.6 mct recorded over the life of mine,” he states. “When open pits are coming to an end, you normally expect a gradual fall ing off in production. We achieved the opposite.” Nortje notes that in 2017 the Venetia manage ment team studied ways and means of optimising the open pits to ensure that maximum value could be extracted from them during their last few years of operation without the development of the under ground mine being in any way negatively impacted. “Basically, we looked at the open pits and the underground as an integrated business,” he says. “The timelines generated by this study suggested that we would finish open pit mining during 2023, a target we bettered by a full year. We also managed to add a few benches and go deeper in K1 than originally planned by pursuing late-stage optimisa tion opportunities. In all, we added around US$400 million in value while still finishing early. It’s a phe nomenal achievement.”

Outgoing General Manager of Venetia Mine, Gerrie Nortje.

Outgoing General Manager of Venetia Mine, Gerrie Nortje and employees pose for the camera at the pit closure celebrations.

14  MODERN MINING  May 2023