TOMRA

Lucara Diamond Corporation owns the Karowe diamond mine in Botswana, which has been in production since 2012. The mine is recognised as one the foremost producers of very large, high-quality Type IIA diamonds in excess of 10.8 carats. Historic recoveries include the 1,109 carat Lesedi La Rona – the second-largest gem quality diamond ever found – and the 813 carat Constellation diamond. Lucara’s success at the Karowe mine continues, most recently with rare gem quality blue and pink diamonds recovered in September 2019.

TOMRA’s technology and know-how unlocks the massive potential of the Karowe mine

Initial work on the mine was carried out by previous owners in the 1970s with the technology available at the time, which had its limitations: “what we realised in looking at the diamonds that resulted from that work is that many of them were actually broken,” explains Eira Thomas, CEO of Lucara. “When production started, it became apparent that the diamond population was quite coarse, and that necessitated a re-think on how we could adjust or optimise flow sheet focused on diamond value preservation. That was our real focus and goal in starting the conversation with TOMRA, about how can we do this better, how can we actually get diamonds out of our mineralized ore in a more efficient way and in a way that actually maximizes the value of those diamonds and minimizes the damage of those goods.”

The AK6 Kimberlite found in the Karowe presents a difficult challenge, as John Armstrong, Vice President, Technical Services for Lucara explains: “it has a very high Dense Media Separation yield, in that up to 10 to 15% of the material that would go into the plant would report as a heavy-metal concentrate, making it a very difficult ore body to process in a traditional diamond processing scenario. We undertook a series of testing campaigns and investigations to explore alternative technologies. We elected to go with TOMRA as our partner in moving forward in getting this technology to the mine into part of the circuit that hadn’t been envisioned previously.”

TOMRA’s solution delivered very quickly, exceeding all expectations: “When we put in the large diamond recovery circuit in 2015, it was within 2 weeks of making this investment, which was somewhere around 30 to 35 Million dollars, that we recovered those two exceptionally large diamonds, so in this case it was under 2 weeks we’d already had two times our return on that investment,” says Eira Thomas.

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TOMRA’s true collaborative, partnership approach stands out and delivers

The Lucara project clearly shows that TOMRA stands out not only for its industry-leading technology but, very importantly, for its extensive know-how and approach to working with customers, which it views as a true business partnership.

Eira Thomas explains the reasons for their choice of working with TOMRA: “We felt, certainly, that the technology that TOMRA offered was the best. But, more importantly, I think it was really around the approach, the attitude of collaboration and willingness to actually work with Lucara as we undertook to solve this problem, and that to us was a very appealing element because we weren’t entirely certain what the solution was going to be, we just felt that by working with a team of experts that understood the problem and had technology that could help us, we could together come up with a solution that made sense. And I think that was the big opportunity for us as we sought in working with TOMRA.”

John Armstrong agrees: “As part of the process that made working with TOMRA unique and special was their willingness to view the relationship between Lucara and TOMRA as a partnership, and we were both investing in this, and we were both going to learn a lot from it, and we relied on each other to ensure that we were going to be successful.”

TOMRA: a game changer for the future of diamond mining

“I think the Lesedi and The Constellation recoveries really did open up a lot of eyes, and I think it opened a lot of minds to the idea that technology can and will make a big difference to not only existing diamond mining operations, but future mining opportunities and it’s a great testament to the efforts that we’ve made in collaboration with TOMRA to really get out and tell the story,” comments Eira Thomas.

John Armstrong agrees: ‘With the early record-breaking diamond recoveries, “we were able to demonstrate to the world that we can recover large high-quality gem stones using the TOMRA technology and using the systems and processes that we have in place at the Karowe mine. And we look forward to challenging the convention further with other innovations that we will employ with TOMRA going forward.’

Further information:
TOMRA Sorting Mining
www.tomra.com/mining

TOMRA’s advanced sensor-based sorting technologies offer mining operations the dual benefits of energy efficiency and the ability to recover valuable ore even from sub-economic deposits or dumps. This has become increasingly relevant as the mining industry – a very large consumer of energy – is shifting towards a Green Mining approach to reduce its environmental footprint in the face of climate change, while running profitable operations.

Tord Svensson, TOMRA’s Head of Sorting Mining, explains: “For a mining company to become more sustainable and profitable, it requires a shift in focus that places more value on potentially limited commodities like water and ore. To achieve an environmentally-focused and efficiency-oriented production process – which is integral to Green Mining – it is necessary to implement solutions right from the beginning of the process. This is where ore sorting equipment comes in: using these technologies in the early stages of mining reduces waste material and shrinks the carbon footprint, while increasing profitability.”

TOMRA is a leading pioneer of sensor-based sorting technologies, which are able to give a significant contribution to a more environmentally sustainable approach in mining. It offers smart technologies for sorting and separating a variety of valuable substances (Figure 1). Its solutions range from industrial mineral processes to sorting gemstones, ferrous and non-ferrous metals, coal and other fuels and slag metal. The sensor-based sorting technology by TOMRA not only significantly reduces the amount of energy and water required compared to more traditional methods such as grinding and DMS (Dense Media Separation), but also maximizes the efficiency and quality recovery of valuable ores.

X-Ray Transmission (XRT), one of TOMRA’s leading solutions, separates dry material of various ore and minerals based on their atomic density, irrespective of surface properties and thickness. This means that it is not necessary to crush or grind every rock into smaller particles, which results in massive savings of energy, water, and their related costs. Considering that grinding is the most energy-intensive part of the production cycle, as an estimated 50-75% of the energy used in mining is for the liberation and comminution of ore and minerals¹, this technology can have a significant impact on the sustainability and profitability of a mining operation.

Pre-concentration techniques like sensor-based sorting have been proven to reduce energy consumption by about half, resulting in a considerable reduction of the CO₂ footprint and providing a highly cost-effective solution.

TOMRA has created a Green Counter that displays on its website the total amount of CO₂ reduced through the utilization of TOMRA’s sorting machines in real time. It uses the smart technology within the equipment, which records the amount of rock sorted and eliminated, as well as throughput and total hours of operation. With this data, TOMRA and mining companies are able to calculate the energy in kWh saved by not treating the waste which has been removed by the sorters. The amount of energy saved is converted into CO₂ equivalents, which in turn are converted into CO₂ metric tons. Through the use of TOMRA sorting machines, client companies have saved 123,696 metric tons of CO₂ in 2018 alone.

TOMRA’s sorting solutions have proven to be more than just technological innovation – they are also considered the benchmark for industry standards in both efficiency and sustainability. TOMRA remains committed to evolving its technology with a clear focus towards preserving our shared natural resources.

¹Source: “The Mining Industry and the Circular Economy” Mines – NREL Joint Workshop September 13, 2018

Further information:
TOMRA Sorting Mining
www.tomra.com/mining