Tag Archives: XRT

TOMRA completes the diamond recovery loop with new XRT solution

Comminution of minerals, Diamond mining, IoT, Mineral processing, Mining equipment, Mining services, Mining software, , , , , ,

TOMRA Sorting Mining says it is breaking new ground with a “unique” X-ray Transmission (XRT) Final Recovery solution that guarantees 99% diamond recovery.

With the new introduction, TOMRA is the first company in the industry able to supply a full diamond recovery solution using XRT technology from 2-100 mm, coupled with all the benefits of cloud computing for monitoring and managing the entire process, it said.

The new TOMRA COM XRT 300/FR final recovery sorter delivers concentration factors of up to one million with limited stages and is the only solution on the market that guarantees more than 99% diamond recovery, according to the company.

“The new sorter stands out for the high sorting efficiencies, the high diamond-by-weight concentrate, and the benefits deriving from its focus on a single consistent detection principal, diamonds,” the company said. “With this new introduction, TOMRA offers a complete partnered diamond recovery ecosystem with a flowsheet covering the entire process – from concentration to final recovery and sort house – and includes custom development with the end-user all the way to installation, then continued management of the asset and support with specialised services and training.”

The TOMRA COM XRT 300/FR is the latest step in TOMRA’s long-term diamond sector strategy, Geoffrey Madderson, Diamond Segment Manager for TOMRA Sorting Mining.

“We always had this clear objective, but the technology just didn’t exist,” he said. “We knew that to achieve our goal, we would need extremely advanced sensor technology. We have been working in-house on the development the new ultra-high resolution sensor more than five years, and now we are able to close the loop: the COM XRT 300/FR is the last piece within our recovery process, covering the final recovery and sort house applications to produce an ultra-high diamond-by-weight concentrate.”

TOMRA says its holistic approach and unique offering has earned a strong market trust in its XRT technology. As a result, the first three TOMRA COM XRT 300/FR sorters produced have already been sold to customers, all of whom purchased the machines on the back of their experience of previous TOMRA sorters.

The makeup of the TOMRA COM XRT 300/FR sorters sees input material evenly fed via a vibration feeder onto a conveyor belt. An electric X-ray tube creates a broad-band radiation, which penetrates the material and provides spectral absorption information. This is measured with an X-ray camera using DUOLINE® sensor technology, which focuses on a single, constant property of the material, density, it explained.

The advanced ultra-high resolution sensor information is processed and analysed by our TOMRA’s new Image Processing Pipeline to provide a detailed “density image” of the material, allowing it to be separated into high- and low-density fractions. If diamonds are detected, it commands the control unit to open the appropriate valves of the ejection module at the end of the conveyor belt. The detected diamonds are separated from the material flow by jets of compressed air. The sorted material is divided into two fractions in the separation chamber.

The tight tolerances and accurate alignment of the new ultra-high resolution sensor results in a high-quality picture that ensures a clear discrimination between diamonds and low-density materials down to 2 mm, according to TOMRA. The sorter features high-speed valves with a fine nozzle pitch, which significantly reduces non-diamond material in the concentrate. The result is ultra-high diamond-by-weight concentrate with a guaranteed recovery of more than 99%, the company claims.

It is possible to replace multiple sorting stages with a single TOMRA COM XRT 300/FR sorter all the way down to hand sorting, according to the company. In the final recovery application, the sorter targets the highest tonnage through the sorter that can be achieved with the highest recovery efficiency, which ranges from five tonnes to one tonne. As a result, the operation benefits from a smaller footprint and achieves much better grade.

It is also possible to replace hand sorting with a TOMRA COM XRT 300/FR. In a sort house application, it targets the highest diamond-by-weight concentrate possible, with about half the tonnage than final recovery, bringing multiple benefits. It removes the traditional bottlenecks around hand sorting efficiencies and eliminates the human error factor, the company says. In addition, it provides a high level of security by protecting the product from human intervention.

TOMRA’s partnered diamond recovery ecosystem includes consultation services during the development of the system and throughout the lifecycle of the equipment, support running the sorters, and help with specialised services and training. The company has also leveraged digital technologies to provide effective support, through its Virtual Demonstration and Test Solution and features such as the TOMRA Visual Assist Augmented Reality tool for remote assistance.

“With TOMRA, the customer’s entire recovery system falls into one ecosystem,” explains Madderson. “This allows for better compatibility and interconnectivity between the different applications of the recovery process. It gives our customers the full benefit of using cloud computing through our TOMRA Insight platform, which turns our sorters into connected machines. This enables customers to monitor and manage their recovery process in one easy-to-access place for both on-site and off-site management teams.”

TOMRA has set up a showroom dedicated to demonstrations of the TOMRA COM XRT 300/FR sorter at its Test Center in Wedel, Germany. Later in the year, TOMRA will also offer virtual demonstrations for those unable to travel to the Test Center.

Vast Resources to leverage new equipment and XRT ore sorting at Baita Plai

Base metals, Comminution of minerals, Mine operation news, Mineral project development, Mining equipment, Mining services, , , , , , , , ,

Vast Resources has devised a new mechanised mine plan for its Baita Plai polymetallic mine in Romania that will see mining capacity increase by 65% and ore sorting employed to increase mill feed grades.

The new mine plan includes the acquisition of three LHDs (including at least one narrow-vein electric LHD), an Aramine face jumbo drill rig, two Resemin Muki 22 long hole drilling rigs and a TOMRA X-ray Transmission (XRT) ore sorter.

Execution risk is expected to be significantly reduced compared with the old labour-intensive plan through the employment of senior international staff; the use of increased mechanisation; and the fact that shortly, with the expediated development plan now possible through the new equipment, the mining areas will be in areas newly drilled by the company and not in less stable old mining areas, the company said.

The company, in co-operation with TOMRA Mining, has concluded an initial investigation on ore from Baita Plai as part of the development of the new mining and processing plan. The objective of the work was to determine the amenability of ore from Baita Plai to be pre-concentrated using TOMRA sensor-based sorting technologies to produce a high-grade pre-concentrate, pre-milling feed.

“The study showed a clear amenability for the ore to be separated using TOMRA’s advanced XRT technology to identify both massive mineralisations, as well as fine mineral inclusions, using its proprietary combination detection algorithms to produce a high-grade pre-concentrate and eliminate non-grade containing waste material,” the company said.

The XRT implementation and processing plant upgrades are set to be completed by December 2021, the company said, with mill feed grades expected to be concentrated by 1.25-1.75 times. This would see the sensor-based sorter shift 60% of tonnage into the accept stream for the mill and 40% into the reject stream, with a 92% yield in the accept tonnage.

The new mine plan presents a cost reduction of 21% in dollars per mined tonne with an operational efficiency of 63 tonnes per total employee costed (TEC) at steady state, versus the previous plan efficiency metric of 43 tonnes per TEC, Vast Resources said. It also sees mining capacity rise to 22,000 t/mth, from 13,300 t/mth.

Andrew Prelea, Chief Executive Officer of Vast Resources, said: “This is a robust and comprehensive mine plan which has been developed using rigorous technical parameters. On behalf of the board, I believe the plan set out to shareholders today represents a benchmark for us to deliver on over the coming years in tandem with our broader expansion plans at Baita Plai and across our wider portfolio.”

TOMRA boosts sensor-based ore sorting process with key updates

Comminution of minerals, IoT, Mineral processing, Mining equipment, Mining services, Mining software, , , , , , , , ,

TOMRA Sorting Mining has introduced the TOMRA ACT user interface together with a new image processing pipeline and additional process data for TOMRA Insight, all of which will, the company says, enable improvements in the overall sorting process for greater productivity and profitability.

The new TOMRA ACT graphical user interface (UI) brings a fundamental change in the way customers interact with their machines, making it easy to control the work flow in their sorting process with simple, intuitive touch gestures and actions on the screen, according to the company.

The UI provides sorting information and real-time process data at a glance through easy-to-understand graphics. With this clear information, the operator can better monitor the sorting process and make fast adjustments at any time, the company claims. The quick feedback on machine performance and throughput enables them to optimise the process, maximising productivity and efficiency.

Ines Hartwig, TOMRA Product Manager

Ines Hartwig, TOMRA Product Manager, explained: “Throughout the development process of TOMRA ACT, we conducted many in-depth discussions with our customers to ensure we provided them with an interface that would improve the performance of their sorters, benefitting their business. We have been testing it with customers and the feedback has been very positive; in particular about the ease of use, even remotely, which facilitates controlling the process and adjusting settings.

“With the new interface, customers interact with their sorters in a much more intuitive way and they have better guidance on how to improve the overall handling of the sorters. As a result, they will be able to improve the productivity of their sorting plant and the profitability of their mining operation.”

TOMRA is introducing the new UI on all its current X-ray Transmission (XRT) sorters and is planning to extend it to other machines in its offering at a later stage. Upgrade packages to retrofit previous models of its XRT sorters will also become available.

The new Image Processing Pipeline, meanwhile, analyses the data sent by the sorter’s sensors and cameras. This solution provides TOMRA with even more flexibility to adjust and customise the image calculations according to the application and the customer’s specific requirements to achieve the best possible sorting results.

The enhanced image processing solution also collects detailed process data, such as information on particle size distribution of the feed, belt occupancy for insights on feed tonnages, or data relating to the health of the sorter. All these statistics are fed to TOMRA Insight, the cloud-based data platform, adding to the process information it has already received. TOMRA said: “This enables customers to improve the overall sorting process further, taking fast action when changes occur in upstream equipment or in the material’s composition. They are able to better monitor and control their processes, the feed material and the sorted fractions, improving their profitability.”

The new enhanced Image Processing Pipeline, and additional data fed to TOMRA Insight, have already been introduced on TOMRA XRT sorters and will in the future be extended to other products.

Peel Mining’s South Cobar preliminary flowsheet to factor in ore sorting

Base metals, Comminution of minerals, Mineral processing, Mineral project development, Mining services, Precious metals, , , , , , , , , , , , , , , ,

Peel Mining says positive results from ore sorting test work at the Southern Nights and Mallee Bull deposits, part of its 100%-owned South Cobar Project, in western New South Wales, Australia, provide encouragement for the inclusion of this pre-concentration technology into future process plant design.

So encouraged by this testing is Peel that it has engaged GR Engineering to integrate ore sorting technology into an updated processing plant technical report for the project.

At the same time as this, Peel announced that GR Engineering had recently completed a preliminary process plant technical report for South Cobar that considers crushing, grinding, gravity, flotation and cyanidation process stages for the recovery of gold, silver, copper, lead and zinc from the various mineralisation styles within Peel’s deposits.

Meanwhile, the recently received positive preliminary ore sorting test work results from work undertaken on diamond drilling samples shows there is potential for improvements in the flowsheet.

The ore sorting test work, completed in conjunction with ongoing metallurgical studies, was undertaken by Steinert and TOMRA.

Steinert ’s test work on Southern Nights mineralisation demonstrated strong recovery and upgrade potential with two size range samples returning, on average, circa-93% Zn, circa-91% Pb, circa-91% Ag, circa-87% Cu and circa-82% Au recoveries to an average of circa-54% of the feed mass (circa-46% of feed mass rejection) increasing the lead and zinc grades by 61% and 64%, respectively.

TOMRA’s test work on Mallee Bull mineralisation achieved significant waste mass reductions while maintaining very high copper recoveries (≥95% for the higher-grade breccia copper and massive sulphide copper samples), the company said. A lower grade breccia copper sample upgraded from 0.59% Cu to 1.05% Cu with 77% Cu recovery and 56% mass rejection, it noted.

“Positive results from ore sorting at Southern Nights and Mallee Bull deposits provide encouragement for the inclusion of this pre-concentration technology into future process plant design and, as a result, Peel has engaged GR Engineering to integrate ore sorting technology into an updated processing plant technical report,” the company said.

Peel’s Executive Director of Mining, Jim Simpson, said: “The completion of the processing plant technical report by mineral processing solutions experts GR Engineering is a critical first step in understanding the potential composition of the milling infrastructure required for the company’s development plans.

“The detail presented in the report by GR is impressive and the report will form the basis for ongoing preliminary studies for the refinement and improvement of the processing plant design as new information comes to hand.

“We are also very pleased with the potential of ore sorting as part of any future South Cobar project hub’s processing route with initial test work pointing to the amenability of both Southern Nights and Mallee Bull mineralisation to separation using 3D-XRT ore-sorting technology, allowing for the simultaneous rejection of barren or waste material whilst retaining the bulk of contained metal, and in the process, upgrading the value of the ore.”

Simpson added: “Apart from reducing the overall feed mass by the rejection of waste at early stage, other benefits of ore sorting include potentially upgrading lower-grade mineralisation and reducing the size of the processing plant offering potentially reduced capital, power, water and tailings storage needs.”

Lucara recovers second plus-300 ct diamond of 2021 at Karowe mine

Comminution of minerals, Diamond mining, Mine operation news, Mineral processing, Mining services, , , , ,

Lucara Diamond Corp has announced another recovery of significance from its 100% owned Karowe Mine, in Botswana, with its TOMRA X-ray Transmission (XRT) sensor-based ore sorting units, again, helping the miner recover and keep the diamond intact.

A magnificent unbroken Type IIa 378 ct gem quality top white diamond was recently recovered from milling of ore sourced from the M/PK(S) unit of the South Lobe, Lucara reported. This recovery is the second plus-300 ct gem quality diamond to be recovered this year from direct milling of the M/PK(S) unit, a further testament to the strong resource and process circuit performance at Karowe, the company said.

Both the 378 ct and the 341 ct diamonds recovered this year came from the Coarse XRT circuit, Lucara said.

Eira Thomas, Lucara’s CEO, said: “The 378 ct joins a rare and special lineage of exceptional, high value diamonds recovered at Karowe and continues to highlight the wonderful diamond potential of Botswana. Continued and consistent recovery of large diamonds, such as the 378 ct and 341 ct stones, comes at a critical time and provides continued strength and additional foundation to the opportunity to finance and build the underground expansion at Karowe that will see mining continue for at least another 13 years after the open pit ceases operations in 2026.

“We look forward to a safe, productive and busy 2021.”

A 2019 feasibility study looking at a combined open pit and underground future at Karowe showed the company could double the mine life of the operation for $514 million in pre-production capital by developing an underground deposit.

TOMRA XRT units help recover unbroken 998 ct diamond at Lucara’s Karowe mine

Diamond mining, Mine operation news, Mineral processing, Mining equipment, Mining services, , , , , , , , , , ,

TOMRA’s COM XRT 2.0/1200 ore sorters have aided Lucara Diamond’s Karowe diamond operations, in Botswana, once again, recovering an unbroken 998 ct high white clivage diamond from the 100%-owned mine.

The diamond, measuring 67 x 49 x 45 mm, was recovered from direct milling of ore sourced from the EM/PK(S) unit of the South Lobe, and follows a series of significant diamond recoveries during this recent production run, including several top quality clivage and gem-quality stones of 273 ct, 105 ct, 83 ct, 73 ct, and 69 ct in weight.

“The EM/PK(S) forms an important economic driver for the proposed underground mine at Karowe and continues to produce large gem-quality diamonds in line with expectations, a further testament to the strong resource performance at Karowe,” the company said.

Last year, a feasibility study showed the company could double the mine life of Karowe by establishing an underground mine for $514 million in pre-production capital.

The 998 ct diamond (pictured) was recovered in the MDR (Mega Diamond Recovery) XRT circuit that allows for diamond recovery post primary crushing and prior to milling. The MDR circuit has, in the past, treated material in the size range between 50-120 mm. This latest recovery represents the second plus-500 ct diamond recovered from this circuit in 2020, Lucara noted.

Year to date, Karowe has produced 31 diamonds greater than 100 ct, including 10 diamonds greater than 200 ct comprising of the 549 ct Sethunya, and the 998 ct diamond.

Eira Thomas, Lucara CEO, said: “Lucara is extremely pleased with the continued recovery of large high-quality diamonds from the South Lobe of the Karowe mine. To recover two plus-500 ct diamonds in 10 months along with the many other high-quality diamonds across all the size ranges is a testament to the unique aspect of the resource at Karowe and the mine’s ability to recover these large and rare diamonds.

“Operations at Karowe have continued through 2020 and operational challenges, due to COVID-19 restrictions, have been met with professionalism by the team. We look forward to a safe finish to 2020 and continued success at Karowe as we remain focussed on strong operations to ensure maximum resource performance.”

Gowest Gold heads towards production at Bradshaw with help of Steinert XRT ore sorter

Mineral processing, Mineral project development, Mining services, Precious metals, , , , , ,

Gowest Gold is expected to make the leap into production shortly at the Bradshaw gold deposit, in Timmins, Ontario, with all permits secured and a Steinert ore sorter commissioned.

In an update this week, the company said it had received official notice from the Ontario’s Ministry of Energy, Northern Development and Mines that its Mine Production Closure Plan had received final review and filing in accordance with the Ontario Mining Act. This plan provides details for how the Bradshaw mine will be operated and closed, and how the site will eventually be reclaimed once mining activities are completed.

With this permit in hand, Gowest says it has now received all environmental approvals required to bring the mine into commercial production.

On top of this, Gowest said its ore sorter has been commissioned in preparation for sorting the mixed development ore currently stockpiled on surface. This material will be trucked to Northern Sun’s Redstone Mill, in accordance with a toll milling arrangement, where processing is scheduled to begin on the week of November 9.

Gowest previously reported that around 28,000 t of gold-bearing mixed development ore had been collected and stockpiled on site from the company’s ongoing advanced exploration bulk sample program. The company also plans to mine around 15,000 t of stope ore as part of the bulk sample.

The company has previously outlined that run of mine ore from Bradshaw will first be crushed and sent through a dual energy X-ray Transmission ore sorting unit supplied by Steinert US. This was expected to “sharply reduce handling costs and increase gold grades of ore sent for processing”, it said. In a recent presentation, the company said this technology could reportedly double the Bradshaw grade up to 10 g/t Au.

As part of its Phase 1 developments at Bradshaw, Gowest is aiming to ramp up to production of 50,000 oz/y.

Vimy senses Angulari gold-uranium project boost following TOMRA XRT trial

Comminution of minerals, Energy minerals, Mineral processing, Mineral project development, Mining project news, Mining services, Precious metals, , , , , , , , , , , , ,

Ore sorting test work from TOMRA Sorting Australia has Vimy Resources thinking about higher grades, lower capital and operating costs, and the production of precious metals at its majority-owned Angulari uranium-gold deposit in Australia’s Northern Territory.

The ASX-listed company, which has defined an inferred mineral resource estimate of 26 Mlbs of U3O8 (0.91 Mt at 1.3% U3O8) at Angulari, already thought the deposit, part of the Alligator River project, had potential to fit into the first quartile of the global uranium cost curve, but now it has eyes on further improving its cost position.

An ore sorting proof of concept trial conducted by TOMRA using its COM X-ray Transmission Tertiary system factored in a 41.5 kg sample that was obtained from mineralised material collected from drill core that Cameco Australia drilled in 2011 and 2016.

The trial on this material saw the uranium concentrate grade increase from 1.2% to 2% U3O8 (70% increase) with high U3O8 recovery. Alongside this, the sample gold concentrate grade increased from 0.7 g/t to 1.1 g/t (47% increase). On the latter gold work, Vimy said: “This warrants further investigation given no gold processing or recovery test work has been undertaken to date.”

The test work also showed that gold mineralisation is spatially coincident with the uranium mineral resource within the sample.

Some 13.5 kg of this 41.5 kg sample was not sorted due to the high uranium grade, which provides additional upside in future trials, Vimy noted. Other potential by-products were also identified, including platinum and palladium.

All of this bodes well for cutting the capital and operating costs that Vimy was unable to disclose to investors as part of its December 2018 scoping study on the project.

A higher feed grade from ore sorting would likely result in lower operating costs, the company said.

Meanwhile, smaller hydrometallurgical plant circuits would likely be required for the same level of production. Coupled with a potential reduction in acid-consuming phases in the concentrate, ore sorting has the potential to lower reagents (and water) usage and costs on a per lb U3O8 produced basis, noting that expected reagent use is already low, Vimy said.

“A smaller plant would result in a lower overall disturbance footprint with commensurate approvals and capital cost benefits,” it added.

Mike Young, CEO of Vimy, said, “The results of the TOMRA ore sorting trial at the Alligator River project’s Angularli deposit have exceeded our expectations. The high-grade nature of the deposit, coupled with the ore sorting outcomes, enhances the prospect of Angularli’s potential future development as a low-cost uranium operation.

“Our next step is to progress the upgrade trials and investigate the potential for the recovery of high value by-products associated with the uranium mineralisation at the Angularli deposit.”

The Angularli deposit is located in the King River-Wellington Range tenement group which is managed in a joint venture (Vimy 79%: Rio Tinto 21%) with Rio Tinto Exploration Pty Ltd, a wholly owned subsidiary of Rio Tinto Ltd.

Northern Minerals lays the groundwork for Steinert XRT ore sorter installation

Comminution of minerals, Energy minerals, High tech minerals, Mine operation news, Mineral processing, Mineral project development, Mining equipment, , , , , , , , , , , , , , , ,

Northern Minerals is set to commission a Steinert sensor-based ore sorter for use at its Browns Range rare earth pilot plant, in northern Western Australia, after gaining the relevant regulatory approvals for installation of the machine.

The ore sorting equipment concentrates ore prior to the beneficiation circuit by selecting ore and rejecting waste based on X-ray Transmission. This has the potential to double the feed grade and reduce production costs, according to the company.

Both the Western Australian Office of the Environmental Protection Agency and the Department of Water and Environmental Regulation have now cleared the installation and commissioning, with construction commenced on the structural and mechanical equipment (pictured). Commissioning is scheduled for mid-2021.

The total capital investment for the procurement, installation and commissioning of the ore sorter is budgeted at A$5.9 million ($4.3 million), Northern Minerals said.

Previous trials of ore sorting technology at Browns Range, announced in October 2018, identified the potential to double the mill feed grade. This would lead to an increased production rate of heavy rare earth carbonate and a potential lowering of overall operating costs.

Once the ore sorting system is commissioned, Northern Minerals plans to run additional test work at pilot plant scale on all ore types to establish baseline data on feed grade improvements, it said. This work will also help evaluate material flow-through benefits of ore sorting on overall processing efficiencies, feeding into any future commercial, large-scale project feasibility studies at Browns Range.

Northern Minerals says it is also evaluating the economics of further downstream processing options for Browns Range ore.

To date, Browns Range has produced a mixed heavy rare earth carbonate for small-scale export to offtake partners. The options being assessed would take a further step along the supply chain to produce separated heavy rare earth oxides.

The company announced in August 2019 it had commenced a scoping study with US-based K-Technologies Inc to investigate a separation technology on intermediate mixed rare earths materials produced at Browns Range. K-Tech’s technology is focused on continuous ion exchange, continuous ion-chromatography and related advanced separation methodologies.

The study continues to progress well, with positive test results being achieved at K-Tech’s facilities in Florida albeit slower than planned because of constraints associated with COVID-19, Northern Minerals said. However, the company expects to see separated dysprosium and terbium oxides from the study before the end of this year.

Separately to collaborating with K-Tech, Northern Minerals is pursuing studies into traditional solvent extraction to produce oxides from the mixed heavy rare earth material produced at Browns Range.

Northern Minerals CEO, Mark Tory, said: “With approvals in place for the ore sorter and installation now under way, we will be in a strong position to thoroughly evaluate the flow-through benefits of that technology at a pilot plant scale.

“The results will provide a valuable input into future feasibility studies to assess the commercial viability of a large-scale heavy rare earths mining and processing operation at Browns Range.

“In addition to our investment in ore sorting to improve the mill feed grade, we are also committed to assessing opportunities to further unlock value at Browns Range through downstream processing to oxide products, which opens up a wider field of offtake and future project financing opportunities.”

Northern Minerals started producing rare earth carbonate through the Browns Range pilot plant in October 2018 as part of a three-year pilot assessment of economic and temporarily technical feasibility of a larger scale development at Browns Range.

Rafaella considers processing options after positive TOMRA XRT ore sorting tests

Comminution of minerals, Energy minerals, Mineral processing, Mineral project development, Mining services, Precious metals, Water management, , , , , , , , , , , ,

Sensor-based ore sorting test work from TOMRA Sorting Solutions has shown the potential for lowering the planned capital expenditure and operating costs associated with developing the Santa Comba tungsten-tin project in Galicia, Spain, project owner Rafaella Resources has reported.

The “exceptional” ore sorting results showed a 50% rejection of un-mineralised rock and an approximate doubling of feed grade, which would significantly lower the planned process capex and opex, and enhance process efficiency through a simpler process flowsheet, the company said. The 50% cut in process tonnage also reduces the project’s environmental impact, with a far lower volume of waste generated, lower energy consumption per unit of metal produced and reduced water consumption.

The “Grade Recovery Curve” showed the potential for over 90% tungsten recovery with an increased yield of up to 55% of feed mass, it added, while testing of the low-grade ores showed viable recovery from over 2 Mt of mineralisation not currently factored into the project’s economics.

The program tested two bulk samples selected from assayed drill core crushed to two size groups: +8 mm to -20mm and +20 mm to -40 mm. Sample No. 40 was circa-1,100 kg of average grade ore at 0.15% WO3, while Sample No. 41 was circa-250 kg of low-grade ore at 0.05% WO3.

TOMRA’s conclusion in its report was that “the results from this test work were positive for both sizes and samples. Significant upgrades of WO3, as well as high recoveries, were achieved in all test runs for sample ‘40’ using X-ray Transmission (XRT), while leaving rather low grades for WO3 in the waste fraction. A calculation has shown that a 90% recovery of tungsten can be possible at a waste removal of more than 50%.

“The low-grade sample ’41’ could be upgraded by a factor of 1.7 to 3. For further calculations, a waste grade between 0.025 and 0.030 is achievable.”

The success of the XRT sorting tests allows several mining and process options, Rafaella says, including:

  • Simplification of the process;
  • Bulk ore zone mining to reduce operational costs and maximise ore recovery;
  • In-pit sorting and conveying;
  • Bulk underground mining and sorting of wider ore zones using larger and longer stopes;
  • Separate sorting of sub-grade mineralisation; and
  • Sorting of satellite deposit ores prior to hauling to the process plant.

TOMRA estimates a throughput of 1 Mt/y of feed ore and circa-500,000 t/y of pre-concentrate would require two XRT units.

Rafaella’s Managing Director, Steven Turner, said the results from the ore sorting test work have exceeded the company’s expectations.

“The clear discrimination between ore-bearing rock and low grade or barren rock has delivered high recoveries and yields allowing for a simpler process plant,” he said. “The benefits of this simplification will be significant once the metallurgical studies are completed. These results are now being fed into the feasibility study that is in the final stages of completion.

“The company looks forward to providing the market with these exciting updates on the fast tracking of its flagship project over the coming weeks.”

Santa Comba is a brownfield project with a 5.1 Mt JORC 2012 compliant near-surface inferred resource at 0.203% WO3 and 0.014% Sn and an underground inferred resource of 234,000 t at 0.95% WO3 and 0.28% Sn.