How one global diamond producer uses sorting technology and digital solutions to recover unbroken diamonds.
Global diamond producer Lucapa Diamonds owns 70% of Mothae Diamonds, an open-pit mine located in the Maluti Mountains of Lesotho, Africa. The mine started commercial operation in 2019 following the commissioning of its kimberlite processing plant. The mine is known for producing large, high-quality diamonds, and has had significant gem-quality recoveries including a 215 carat D-colour Type IIa, a 204 carat Type IIa, and rare pink, blue and yellow diamonds.
When planning the recovery plant, Mothae turned to TOMRA Mining for a solution: “We wanted to recover large diamonds at the highest sorting efficiency with the highest throughput, and TOMRA met Mothae’s requirements with its modern and innovative technology,” says Macobone Semelane, recovery superintendent.
The recovery plant operates two TOMRA COM Tertiary XRT 1200 sorters: one for fine materials from 10mm to 20mm, and the other for coarse materials from 20mm to 45mm. The ore extracted from the mine is treated through primary crushing, scrubbing and screening, then transferred to the recovery area: “That’s where the TOMRA sorters separate diamonds from the ore,” explains Kothalo Matoli, a recovery mechanician at the mine. “TOMRA sorters help us to recover large diamonds prior to secondary and tertiary crushing, hugely reducing the risk of breakages, and our throughput is high, with 98% efficiency.”
The two TOMRA XRT sorters at Mothae are connected to the TOMRA Insight cloud-based data platform that turns the machines into connected devices generating valuable data and helping operators to control the sorting process. They also feature the TOMRA ACT user interface, which helps optimise the workflow and improve productivity.
Macobone Semelane explains: “As a relatively small and low-grade mine, we are always investigating the latest technologies. With our sorters operating 24 hours a day, seven days a week, we wanted to ensure they were connected to the latest compatible software and hardware.”
“We also wanted to ensure our operators could interact with the sorters and so needed a user-friendly portal. The TOMRA ACT user interface provides a clear view of events and alarms as well as images of belt occupancy. It also shows ejection activity, which is useful.”
“TOMRA Insight has changed the way we run our production because we can monitor our sorters remotely as well as access reports from both machines in one interface,” says Kothalo Matoli. “All the alarms and events are logged on the sorter in real time, allowing us to troubleshoot very fast. My troubleshooting skill has improved a lot.”
TOMRA Insight also stores and backs up all the data generated by the sorters so that the operator can analyse the complete history of each machine. “Digital data is crucial. TOMRA Insight has exceeded my expectations because I can access data whenever I want, wherever I am. I have all the learnings about my sorters, their operation and maintenance. We can also see the belt occupancy and our ejection rate, and understand if a machine is over-ejecting owing to foreign objects in the material, for example. The utilisation of the sorters has improved, enabling us to process more tons and recover more carats.”
“In addition, I can monitor the sorters’ operational and health status from the office or offsite since TOMRA Insight captures and compiles all the data in one interface, generating reports and data analyses, as well as improving data management and analytics. With TOMRA Insight, I expect to see advanced sorting solutions and automated recovery plants in the not too distant future,” adds Macobone Semelane.
The technology also enables a smooth production process since it fine tunes many parameters at the same time. Planning, productivity, quality management and logistics can be accessed by all teams and departments, and staff will be looking at the same near real-time information.
Customer support Macobone Semelane is also impressed with the support TOMRA offers. He says: “The team have been very supportive and their service is excellent.” Kothalo Matoli agrees: “They are available whenever we need them. They help us remotely and if we need somebody on site, they will send someone along.
