A trial of TOMRA’s XRT technology quickly reveals its potential
Jaco Houman, Senior Manager Technical and Projects at Gem Diamond Technical Services, explains: “We had quite a lot of historic tailings material. We had a view that, since we had commissioned a new Coarse Recovery in 2015, we weren’t quite getting all the diamonds we were looking for. We worked with our supplier to improve, but we felt we had reached a ceiling point. That’s when we decided to augment the installed base and contacted TOMRA.”
Gem Diamonds rented a TOMRA COM Tertiary XRT sorter, which was deployed in the second half of 2017 to process historic tailings. “Our objectives were to audit the Coarse Recovery Plant performance, increase diamond recovery, improve the recovered revenue and evaluate the TOMRA unit as a recovery and bulk sorting unit,” says Jaco Houman.
The initiative was a success and the TOMRA sorter delivered on all the objectives Gem Diamonds had set: “During the 6-month rental of this unit, we got a better understanding of our primary recovery efficiencies, we were able to conduct off-line auditing and scavenging activities, we increased our diamond recovery and revenue, and we effectively introduced bulk treatment of historical recovery tailings.”
TOMRA’s XRT sorter exceeded all expectations: “The unit showed that it recovers consistently from the tailings material. The value that came from it spoke volumes about the technology and the potential that could still be obtained with the material available. It cemented the realisation that we needed a recovery unit for scavenging, auditing and second-pass recovery.”
In January 2018, we had pretty much just finished commissioning this unit and we recovered the biggest stone Letseng had ever seen, the 910-carat Lesotho Legend. There was no question about performance after that.