Mining sorting equipment manufacturer TOMRA Mining highlights that its X-ray transmission (XRT) technology, powered by TOMRA Insight, has delivered significant results at the Mothae Diamonds operation, in Lesotho.

Global diamond producer Lucapa Diamonds owns 70% of Mothae Diamonds, a mine located in the Maluti mountains of Lesotho, a region known to produce large, high-value diamonds that command the second-highest dollar per carat for kimberlite diamonds, worldwide.

The mine started commercial operation in 2019 following the commissioning of its kimberlite processing plant. The mine is known to produce large, high-quality diamonds, and has had significant gem-quality recoveries including a 215 ct D-colour Type IIa, a 204 ct Type IIa, and rare pink, blue and yellow coloured 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 Mothae mine recovery superintendent Macobani Semelani.

The recovery plant operates two TOMRA COM Tertiary XRT 1200 sorters: one for fines from 10 mm to 20 mm, and the other for coarse materials from 20 mm to 45 mm.

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 Mothae mine recovery mechanician Kothalo Matoli.

“TOMRA sorters are the best of the best. With them, we are able to recover large diamonds prior to secondary and tertiary crushing, hugely reducing the risk of breakages, and our throughput is high, with 98% efficiency guaranteed,” he adds.

Unlocking the Power of Data

The two TOMRA XRT sorters at Mothae are connected to the TOMRA Insight cloud-based data platform that turns the machines into connected devices that generate valuable data, placing operators in control of the sorting process. They also feature the TOMRA ACT user interface, which facilitates workflow optimisation and improves productivity.

Semelani explains that the miner is always exploring the latest technologies. “We wanted a portal that is user-friendly so our operators can easily interact with the sorters. TOMRA ACT now provides clear visualisation of events and alarms, and captures the images of the belt occupancy. It also shows the ejection activity,” he highlights.

“TOMRA Insight has changed the way we are running our production because we can monitor our sorters remotely and we can access reports from both machines in one interface,” says Matoli. “All the alarms and events are logged on the sorter in real time, enabling me to troubleshoot very fast. My troubleshooting skill has improved a lot.”

In addition, 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. TOMRA stresses that digital data is crucial.

“TOMRA Insight has exceeded my expectations because I can access data whenever I want, wherever I am. I have at my fingertips the learnings about my sorters, their operation and maintenance. “We can 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.With TOMRA Insight, I see advanced sorting solutions in the future and automated recovery plants,” Semelani concludes.