THE development of unique sorting algorithms that allow for extremely high accuracy in detection of diamonds has created significant opportunities for new and cost-effective ways to separate minerals from waste, according to IMS Engineering managing director Paul Bracher. Leading the way is the STEINERT XTS x-ray transmission technology (XRT).
IMS has a joint venture with STEINERT Elektromagnetbau for the supply and development of sensor sorting technology into the mining, industrial minerals and recycling industries.
“The STEINERT XTS is outstanding for recovery of large diamonds, and precise and reliable while finding small diamonds, which are much harder to detect,” says STEINERT business development manager Kai Bertram.
The unit is designed to recover diamonds 4mm and larger but even 3mm diamonds can be recovered efficiently due to the sophisticated algorithms paired with a high pixel resolution of 0.5mm. The STEINERT XTS has a state of the art solution that recognizes all types of diamonds which stands it apart from previous technologies.
A southern African diamond mine famous for its large, top quality diamonds, reports success with two STEINERT XTS sorters used in the mine’s Final Recovery Plant. They are the first XRT sorting systems used in final recovery at any diamond mine.
Extensive test work was carried out at the project to show that the x-ray transmission technology could detect diamonds as predicted. “It was as a result of this test work that we could provide our process guarantees. We tested simulants and diamonds provided by the client with the goal to achieve 100% recovery during test work and we are proud to report that this was achieved,” says Paul Bracher.
During the test work, separation algorithms were further developed for detecting and ejecting diamonds while hardware optimizations were carried out. For this application the equipment had to be re-designed to fit the client’s footprint requirements.
During this process, STEINERT integrated the latest developments in detection equipment as well as improvements in the algorithms developed during the tests. “We were able to customize the sorter to fit the required footprint, while retaining maintainability through using standard components,” says STEINERT CTO Dr Uwe Habicht.
“We improved all areas of performance including detection and ejection into a secure area while obtaining the lowest possible yield to increase the diamond by weight ejected.” XRT will enable the mine to recover large, high-value diamonds early on in the recovery process, which reduces the chance of damage.
During commissioning a 2-carat diamond was recovered from tailings material fed to the machine and shortly after a 50-carat GNT type 2, 75% unbroken diamond was recovered by the STEINERT XTS.
A mine spokesman says he looks forward to continuing to reap the benefits of the STEINERT XTS at this critical stage of the sorting process. “We are pleased to be pioneers for this technology in the diamond industry. The results of the extensive pilot work that we did were indeed most encouraging and this has been verified by a significant 50-carat recovery.”
STEINERT has shown that STEINERT XTS is the cutting edge in diamond recovery and sorting technology with its main advantage being that it detects different x-ray absorption levels of different material types. The resulting x-ray images relate to the atomic make-up of each particle going through the detection zone of the machine.
Therefore, a diamond, which consists of carbon atoms, appears as a light-grey x-ray image when compared to denser waste rock and, because this is sorting on an atomic level, all diamonds, no matter what their physical characteristics, can be detected with the STEINERT XTS XRT.