Tag Archives: x-ray transmission

Ore sorting has role to play in ‘Green Mining’ developments, TOMRA says

TOMRA says its advanced sensor-based sorting technologies can provide mining operations with the energy efficiency and ore recovery benefits they require to reduce their environmental footprints.

The ability to recover valuable ore from even sub-economic deposits or dumps has become increasingly relevant as the energy-intensive mining industry shifts towards a ‘Green Mining’ approach, according to the company.

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 pioneer of sensor-based sorting technologies, offering smart technologies for sorting and separating a variety of valuable substances. 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 not only significantly reduces the amount of energy and water required, compared with more traditional methods such as grinding and dense media separation, but also maximises the efficiency and quality recovery of valuable ores, according to TOMRA.

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 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, according to the company.

“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 minerals, this technology can have a significant impact on the sustainability and profitability of a mining operation,” TOMRA said.

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

TOMRA has created a Green Counter on its website that displays the total amount of CO2 reduced through the use of its 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 company said. “The amount of energy saved is converted into CO2 equivalents, which in turn are converted into CO2 metric tonnes.”

Through the use of TOMRA sorting machines, client companies have saved 123,696 t of CO2 in 2018 alone, the company said.

The company concluded: “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.”

North Arrow brings in Imilingo, TOMRA, Microlithics for modular diamond recovery

North Arrow Minerals says it has engaged Imilingo Mineral Processing of Pretoria, South Africa, TOMRA, and Microlithics Laboratories of Thunder Bay, Ontario, to investigate modular diamond recovery design options incorporating TOMRA’s X-Ray Transmission (XRT) sorting technology at its 100% owned Naujaat diamond project in Nunavut, Canada.

The engagement is with a view to recovering diamonds greater than 3 mm (nominally >0.5 ct) in size from a diamond recovery plant, it said.

North Arrow is currently planning for collection of a 10,000 t bulk sample from the Q1-4 deposit at Naujaat and, as part of this work, has initiated an engineering design and costing study of a small-scale mobile diamond recovery plant. The purpose of the sample will be to evaluate diamond size distribution and value characteristics, with emphasis on a distinct population of high-value, fancy, yellow to orangey-yellow diamonds that have been identified in the deposit, the company said.

Ken Armstrong, President and CEO of North Arrow, said: “We are pleased to be working with Imilingo, TOMRA and Microlithics to study diamond recovery plant design options for use in our continued evaluation of the Q1-4 diamond deposit.

“Over the last number of years, TOMRA’s XRT sorting technology has changed the diamond mining landscape by providing an XRT sorting solution that improves diamond recoveries while reducing breakage and water use compared to more traditional diamond recovery circuits. We believe XRT sorting technology can also be used for the evaluation of diamond deposits and is an ideal recovery solution for the Q1-4 diamond population.

“Locating a small-scale diamond recovery plant at or near the project site will also reduce costs, improve logistics and increase local employment and business opportunities for the residents of Naujaat,” he said.

Imilingo’s iPlant packages combine XRT solutions from the likes of TOMRA to sort and deliver feed material in a clean and well classified state, Managing Director, Jaco Prinsloo, told IM recently. Microlithics Laboratories, meanwhile, provides a number of diamond-specific services to clients in North America.

The focus on recovery of diamonds greater than 3 mm is an important component of the study, the company said, with a significant amount of the cost associated with processing past Q1-4 kimberlite samples related to ensuring and documenting the recovery of smaller diamonds (down to 1 mm in size).

Armstrong added: “While information on the 1 mm to 3 mm diamonds is important, most often the value of these diamonds does not impact the potential viability of the deposit being tested. This is certainly the case for Q1-4 where the value and size distribution of the fancy coloured diamond population will be critical in determining the economic potential of the deposit.

“We are therefore looking to design a small-scale mobile plant that can produce a hand-sortable concentrate for the recovery of +3 mm diamonds while saving significant costs and time delays associated with shipping bulk samples south for processing.”

Locating a diamond recovery plant at Naujaat as part of the Q1-4 bulk sampling program is possible due to the deposit’s proximity to marine transportation infrastructure and the improved accessibility that will be provided by a proposed new community access trail, the company said.

TOMRA XRT technology recovers massive diamond at Lucara’s Karowe mine

Lucara Diamond Corp claims to have found and recovered one of the largest diamonds in recorded history at its Karowe operation in Botswana.

The 1,758 ct diamond was recovered through Lucara’s X-ray Transmission (XRT) circuit, commissioned in April 2015 by TOMRA Sorting Mining.

Lucara said it is the largest diamond recovered in Botswana, and the largest diamond to be mined at Karowe to date. It comes on top of the 1,111 ct diamond the company recovered in 2015.

“Weighing close to 352 g and measuring 83 mm x 62 mm x 46 mm, the diamond has been characterised as near gem of variable quality, including domains of high-quality white gem,” Lucara said.

Since commissioning of the XRT circuit in 2015, a total of 12 diamonds in excess of 300 ct have been recovered at Karowe, including two greater than 1,000 ct, from a total production of around 1.4 Mct. Of the 12 plus-300 ct diamonds recovered, 50% were categorised as gem quality with 11 sold to date generating revenue in excess of $158 million, Lucara said.

Geoffrey Madderson, Diamond Segment Manager for TOMRA Sorting Mining, said: “As the largest diamond ever recovered by a mechanical process, it reinforces the unparalleled value XRT offers kimberlite and diamond mining companies. Lucara’s innovative strategy, in combination with TOMRA’s world-class sensor technology, has once again proved an enormous success.”

Eira Thomas, Lucara’s CEO, said: “Lucara’s technologically-advanced, XRT diamond recovery circuit has once again delivered historic results. Karowe has now produced two diamonds greater than 1,000 ct in just four years, affirming the coarse nature of the resource and the likelihood of recovering additional, large, high quality diamonds in the future, particularly as we mine deeper in the orebody and gain access to the geologically favourable EM/PK(S) unit, the source of both of our record breaking, plus-1,000 ct diamonds.”

Imilingo after optimal XRT ore sorting process with iPlant package

X-ray Transmission (XRT) ore sorting is being rolled out across the industry, with companies mining metals and minerals from various parts of the periodic table taking advantage of its sensing capabilities.

South Africa mineral processing company, Imilingo gave an exclusive world-first preview of its latest innovations in sensor-based sorting at the Electra Mining conference in Johannesburg last year. IM caught up with Managing Director, Jaco Prinsloo, to find out more about the company’s offering.

IM: How does Imilingo’s ore sorting offering differ from others on the market?

JP: Imilingo utilises mainly XRT sorting, which is at the forefront of sorting technology in diamond and tungsten applications. Imilingo’s iPlant packages the technology in a way that optimises the efficiency of the sorting machines and provides customers the advantage of dealing with a tried and tested system versus a system made up of a combination of components that are possibly less than ideal for their application. The mobility of the plants also plays a big part in providing the client with a workable solution in African countries and abroad.

IM: Do you use ore sorters from some of the major suppliers and then integrate them into your iPlant offering?

JP: Yes, we have built a strong working relationship with TOMRA Sorting as they are at the forefront of sorting and have a proven track record. The iPlant was specifically developed to prepare material for sorting and delivering the feed material in a clean and well classified state, which increases the efficiency of the sorting process.

IM: How does this customisation result in the optimal conditions for an effective sort?

JP: Efficient material classification and fines removal is key to the sorting process and that is what we focus on when developing a plant. Factors such as operator safety and equipment reliability come standard with our bespoke plants.

IM: Why have you chosen to specialise in diamonds, coal and heavy metals?

JP: Diamond recovery is a clean and relatively simple process, which lends itself to the development of standalone modular plants that can easily be expanded based on a client’s requirements. Tungsten has a much higher specific gravity than the host rock containing it, making it a very effective sort and resulting in a very efficient upgrade of run-of-mine ore. In terms of coal, Imilingo had a test plant running in Middelburg (South Africa) that was relatively successful but not commercially viable at the time due to market constraints.

IM: Have you carried out any commercial coal installations?

JP: No, we have only run our own test plant but believe the coal market is up for the taking in terms of coal sorting. Based on the running of our test plant, we believe that there remains a great opportunity within the coal market for utilising XRT sorting.

IM: Since showcasing your offering at Electra Mining in September, what interest have you had from the mining community in terms of using your solutions?

JP: We have had many enquiries regarding our sorting and dredging solutions. The nature of mining projects is that time is required for projects to mature and convert into actual sales. We believe the main effect of the Electra show was to establish our name in the marketplace and create awareness of our offering, which has been achieved.

The upcoming IM March issue will feature an article on ore sorting