Tag Archives: ore sorting

MineSense to expand XRF ore sorting presence at Copper Mountain mine

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MineSense Technologies says the use of its ore characterisation and sorting technology is seeing improvements in both the ore from waste recovery and ore dilution at Copper Mountain Mining Corp’s namesake mine in British Columbia, Canada.

Having deployed the company’s ShovelSense solution on two shovels and a wheel loader in 2020, Copper Mountain now has plans to install ShovelSense on the two remaining shovels in 2021, along with the first trial installation of BeltSense to explore additional innovation concepts, Don Strickland, Chief Operating Officer at Copper Mountain Mining Corp, said.

Jeff More, President and CEO of MineSense Technologies, said: “Copper Mountain has been a fantastic partner to work with, initially to support us in our scale-up on hydraulic shovels, and then with rapid commercial deployment once the design was stabilised.

“We are thrilled that they installed three of our ShovelSense Systems in the space of five months in 2020 and will complete installation of their entire shovel fleet in 2021.”

The MineSense hardware and software went through a two-year evaluation process at Copper Mountain prior to the solution going commercial, Copper Mountain stated in a recent technical report.

The ShovelSense system improves orebody visibility bucket by bucket in real time during the loading process, according to the company. Trucks are then automatically diverted to the correct location, increasing value and revenue realised during the mining process. The technology also creates reductions of CO2 emissions per tonne of ore produced, consumption of processing chemicals and reagents, energy and water, while maximising metal recovery.

BeltSense, meanwhile, is used on conveyance at different points of the mine operation. It can be used sequentially and in conjunction with ShovelSense to maximise the ore concentrating impact, taking a first cut at the haul point and second further downstream, MineSense says.

Both systems leverage X-ray Fluorescence sensors to carry out the sorting process.

NexGen marries ESG and financials in Arrow uranium project feasibility study

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NexGen Energy CEO, Leigh Curyer, says the company’s Rook I uranium project has earnt its place as one of the “leading global resource projects with an elite ESG profile” after the publication of feasibility study results on the project’s Arrow deposit in the Athabasca Basin of Saskatchewan, Canada.

The study was completed jointly by consultants including Stantec, Wood and Roscoe Postle Associates (now part of SLR Consulting), with other technical inputs completed by sub-consultants.

Financial highlights from this study included an initial capital bill of C$1.3 billion ($1.03 billion) repaid with a post-tax net present value (8% discount) of C$3.47 billion based on a $50/Ib uranium price. From years 1-5 average annual production was due to come in at 28.8Mlb of uranium oxide, with average production over the life of mine of 10.7 years of 21.7 MIb/y.
The company laid out plans for a 1,300 t/d mill processing an average feed grade of 2.37% U3O8.

Listed within the “top five feasibility study outcomes” was enhanced environmental performance, with NexGen saying an optimised facilities layout had reduced the project footprint by around 20% and lowered on-site personnel transportation and ore haulage.

Optimised shaft sizing, water usage through advanced water recycling, and plant engineering reflected elite environmental standards, it added.

“With respect to the proposed shaft, mine workings and underground tailings management facility (UGTMF) locations, geotechnical and hydrogeological testing validated highly competent rock with no significant alteration, no major structures, and low hydraulic conductivity,” the company said.

The mine plan at Arrow was based on conventional long-hole stoping using the 239.6 MIb of declared reserves, the company said.

“Geotechnical studies during the feasibility study re-emphasised the conventional long-hole stoping mining method, including the use of longitudinal and transverse stopes, 30 m level spacing, and the nominal stope strike length of 12 m to 24 m,” it said. “This represents an excellent stope stability range for underground mining in the highly competent conditions.”

Given the competency and conditions of the underground environment, all waste streams from the process plant are planned to be stored underground in the UGTMF, while process water streams will be treated on surface in the optimised effluent treatment plant, NexGen said.

The underground workings will be accessed by two shafts, with the production shaft supporting personnel movements, materials, ore, waste and fresh air. The production shaft was increased to 8 m in diameter (from 6.5 m in diameter in the prefeasibility study (PFS)) to optimise radiation and ventilation management, ensuring the mine is elite from a safety perspective, the company said.

“Additionally, the production shaft will have divided compartments, ensuring that fresh air and personnel entering the mine, remain isolated from ore being skipped to surface,” it added.

The exhaust shaft was ultimately decreased to 5.5 m in diameter (from 6.5 m in diameter in the PFS) and will be used for exhaust air and emergency secondary egress, NexGen said.

Like some other projects in the region, shaft freezing will be required to a point to secure the underground project, NexGen confirmed.

In terms of processing, NexGen said extensive test work and engineering had determined that proven technology in a conventional uranium processing flowsheet is most effective to produce uranium oxide from the Arrow deposit.

The main components of the processing plant are ore sorting; grinding; leaching; liquid-solid separation via counter current decantation and clarification; solvent extraction; gypsum precipitation and washing; yellowcake precipitation and washing; yellowcake drying; calcining and packaging; and tailings preparation and paste tailings plant.

Metallurgical testing resulted in supporting and refining process design parameters, with the process recovery of 97.6% confirming the predictable nature of the processing flow sheet, it said.

“The feasibility study also confirmed that all processed waste streams can be stored in the UGTMF and no surface tailings facility is required,” NexGen said. “The UGTMF is a reflection of NexGen’s industry-leading environmental design approach, contributing to the significant reduction of the project’s surface footprint, and representing an opportunity to implement best practice of progressive closure of tailings facilities during the operational phase of the mine.”

A feasibility study drill program validated the geotechnical conditions and favourable conditions for the UGTMF, with the study also optimising the geotechnical design, size and sequencing of the UGTMF included in the mine plan.

The study test work demonstrated paste fill strength met or exceeded all requirements set in the feasibility study design for a potential paste-backfill to be used for underground stope stability.

In terms of the timeline to production, NexGen said it planned to submit its Environmental Impact Statement in the second half of this year, along with relevant licences.

Anglo American Platinum’s modernisation drive to continue into 2021

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Anglo American Platinum says it is looking to deliver the next phase of value to its stakeholders after reporting record EBITDA for 2020 in the face of COVID-19-related disruption.

The miner, majority-owned by Anglo American, saw production drop 14% year-on-year in 2020 to 3.8 Moz (on a 100% basis) due to COVID-related stoppages. Despite this, a higher basket price for its platinum group metals saw EBITDA jump 39% to R41.6 billion ($2.8 billion) for the year.

As all its mines are now back to their full operating rates, the company was confident enough to state PGM metal in concentrate production should rise to 4.2-4.6 Moz in 2021.

Part of its pledge to deliver more value to stakeholders was related to turning 100% of its operations into fully modernised and mechanised mines by 2030. At the end of 2020, the company said 88% of its mines could be classified as fully modernised and mechanised.

There were some operational bright spots during 2020 the company flagged.

At Mogalakwena – very much the company’s flagship operation – Anglo Platinum said the South Africa mine continued its journey to deliver best-in-class performance through its P101 program.

Rope-shovel performance improved to 26 Mt in 2020, from 15 Mt in 2019, while drill penetration rates for big rigs increased from 15 m/h, to 16.7 m/h. Alongside this, the company said its Komatsu 930E truck fleet performance improved to 298 t/load in 2020, from 292 t/load in 2019.

These were contributing factors to concentrator recoveries increasing by two percentage points in 2020 over 2019.

During the next few years, the company has big plans to further improve Mogalakwena’s performance.

In 2020, the mine invested R500 million in operating and capital expenditure, which included commissioning a full-scale bulk ore sorting plant, coarse particle rejection project and development of the hydrogen-powered fuel-cell mining haul-truck (otherwise referred to as the FCEV haul truck).

First motion of the 291 t FCEV haul truck is still on track for the second half of 2021, with the company planning to roll out circa-40 such trucks from 2024.

Anglo Platinum said the bulk sorting plant (which includes a Prompt Gamma Neutron Activation Analysis and XRF sensor-based setup, pictured) campaign at the Mogalakwena operation is due to end this quarter.

The company’s hydraulic dry stacking project is only just getting started.

This project, which involves coarse gangue rejection before primary flotation for safer tailings storage facilities, is expected to see a construction start in the June quarter, followed by a campaign commencement and conclusion in the September quarter and December quarters, respectively.

On another of Anglo Platinum’s big technology breakthrough projects – coarse particle rejection for post primary milling rejection of coarse gangue before primary flotation – the company plans to start a campaign in the December quarter of this year and conclude said campaign by the end of the March quarter of 2022.

The company also has eyes on making progress underground at Mogalakwena, with a hard-rock cutting project to “increase stoping productivity and safety” set for Phase A early access works this year. This project is set to involve swarm robotics for autonomous, 24/7 self-learning underground mining, the company said.

Lastly, the company’s said the digital operational planning part of its VOXEL digital platform had gone live at Mogalakwena. VOXEL is expected to eventually connect assets, processes, and people in a new digital thread across the value chain to create a family of digital twins of the entire mining environment, the company says. Development is currently ongoing.

Looking back to 2020 performance at the Unki mine, in Zimbabwe, Anglo reflected on some more technology initiatives related to R26 million of expenditure for a digitalisation program. This included installing underground Wi-Fi infrastructure, as well as a fleet data management system to track analytics on primary production equipment. The company says these digital developments will enhance real-time data analysis, improve short-interval control and overall equipment effectiveness.

To step up mechanisation of its PGM operations at Amandelbult, Anglo American Platinum is also investing in innovation.

This includes in-stope safety technologies such as split panel layouts to allow buffer times between cycles, creating safer continuous operation and reduced employee exposure; improved roof support technology and new drilling technologies; a shift to emulsion blasting from throw blasting; and safety enhancements through fall of ground indicators, 2 t safety nets, LED lights, and winch proximity detection.

Meanwhile, at the company’s Mototolo/Der Brochen operations, it is working on developing the first lined tailings storage facility at Mareesburg in South Africa to ensure zero contamination of ground water. The three-phase approach adopted for construction of this facility will be completed this year.

Hochschild’s Inmaculada set for ore sorting pilot plant

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Hochschild says it has approved a $7 million budget to construct an ore sorting pilot plant at its Inmaculada gold mine in Peru in 2021.

The investment follows previous test work carried out with both TOMRA and Steinert. This saw the company conduct initial bulk testing in Germany with both companies and a 20-t pilot scale test with Steinert in Brazil.

The company also enlisted the help of Ausenco to carry out a prefeasibility study on applying ore sorting at Inmaculada.

In the company’s 2019 preliminary results presentation back in February, Ramón Barúa, Hochschild Mining Chief Financial Officer, said ore sorting could prove particularly useful at the Millet and Divina veins at Inmaculada.

He said, in addition to consulting with TOMRA, Steinert and Ausenco, the company had been working in-house to improve the sensors and the algorithm that separates the ore from the waste in these sorters, with the technology showing a clean separation between the quartz-based mineralisation and the andesite holding the rock at Inmaculada.

In its latest financial year results released today, Hochschild said of the ore sorting investment: “We believe this project may eventually deliver significant improvements in recoveries at the mine and potentially help to optimise other key projects in Hochschild’s portfolio.”

For 2020, the company recorded overall production of 289,293 oz of gold-equivalent at an all-in sustaining cost of $1,098/oz of gold equivalent. Inmaculada remained the cornerstone of the company, producing 176,086 oz of gold-equivalent.

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

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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.”

Capstone prepares Cozamin for introduction of paste backfill, dry-stack tailings

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An updated Technical Report on Capstone Mining’s Cozamin copper-silver mine in Zacatecas, Mexico, has shown the potential for a mine life extension to 2031, and a plan for dry-stack tailings and underground paste backfill. At the same time, the company says it is studying the use of “innovative mining techniques and enhanced pillar recovery” to make the most of existing reserves and resources.

The updated life of mine plan released outlined average annual copper production of 51.2 MIb (23,224 t) of copper and 1.6 Moz of silver production over 10 years at average C1 costs, including the 50% silver stream, of $1.02/Ib of payable copper. From 2021 to 2027, average annual production is slated to be 58.8 MIb of copper and 1.7 Moz of silver.

The company said a planned ramp-up to 3,780 t/d, or 1.38 Mt/y, by the end of March quarter is on track, with a new section of ramp to open the one-way traffic circuit to debottleneck the mine (pictured) completed in early December 2020, ahead of schedule.

Reserves increased by 39% and now stand at 14.1 Mt, relative to April 30, 2020. Contained copper and silver increased by 37% and 49%, respectively, with around half of this increase due to recovery of high-grade pillars using paste backfill, Capstone said.

The miner said “tailings management transformation” activities were progressing on schedule at site, including feasibility-level design and studies in support of permitting a filtered (dry stack) tailings storage facility.

“This conversion from a slurry tailings impoundment aligns with industry leading socio-environmental best practice for tailings management,” the company said.

Meanwhile, a prefeasibility study (PFS) for an underground paste backfill system was completed in December.

The study indicates a paste backfill system will allow ore extraction containing over 100 MIb of copper and 3.1 Moz of silver between 2023 and 2031, which would have otherwise been left as unmined pillars. The PFS design has a capital cost estimate ranging from $41-$45 million and an increase in operating costs of around $7.50/t of ore mined. Capstone says its management has approved the paste backfill project and work has commenced on procurement of long lead items.

The proposed paste backfill system includes a tailings filter plant, a paste mixing plant, twin boreholes to deliver paste underground and an underground distribution system. The system is expected to be commissioned starting in the December quarter of 2022, with ramp-up completed in the March quarter of 2023.

PFS design of these facilities was completed by Paterson & Cooke in December 2020 and a feasibility study is underway with completion expected in April 2021. Mine planning was completed by Cozamin, with design support provided by a geotechnical consultant, and paste backfill operational guidance provided by AMC Consultants.

Within the latest release, Capstone also flagged the initiation of its “Impact23 Growth” project, which has identified areas of exploration excellence, innovative mining techniques and enhanced pillar recovery at Cozamin.

“By 2023, the goal is to further extend mine life, increase environmental and safety standards, and improve operational efficiencies at Cozamin, utilising mineral resources already discovered in addition to testing new targets,” the company explained.

Included among the options are the innovative mining techniques for resource to reserve conversion flagged at the start of this story.

Capstone says a study will be initiated this year to assess alternative mining techniques with the objective of lowering costs and dilution to convert resources to reserves from the indicated resource base. The current mining methods are longitudinal longhole open stoping and AVOCA, with possible alternatives to be studied including cut-and-fill, drift-and-fill and longhole open stoping with ore sorting technology.

Brad Mercer, Capstone’s SVP and Chief Operating Officer, said: “The life of mine plan announced today maximises extraction of the orebody’s high-grade core by deferring stoping in this area until the paste backfill plant is in operation in 2023. Projected production averages nearly 60 MIb of copper per year for seven years at first quartile costs.

“The Impact23 Growth project that we are kickstarting today is aiming to demonstrate in a 2023 technical report how Cozamin can sustain these levels of performance well into the 2030s.”

Darren Pylot, Capstone’s President and CEO, added: “After 14 years in operation, the best years of Cozamin are ahead. The mine is world class with sustainable low costs and leading safety and environmental performance entrenched throughout the organisation. The growth initiatives are supported by an entrepreneurial fabric at Capstone, as we embrace innovation and technology to create high impact value for our shareholders.”

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

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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.

Hatch to commercialise CRC ORE’s Grade Engineering services

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CRC ORE says it has taken an exciting step forward with Hatch, signing a deal that allows the multidisciplinary management, engineering and development consultancy to commercialise its Grade Engineering® Consulting Services.

Developed by the Brisbane-based Cooperative Research Centre for Optimising Resource Extraction (CRC ORE), Grade Engineering enables miners to reduce their energy, water and waste signatures while enhancing the productivity and profitability of their operations, according to CRC ORE.

It is an integrated approach to coarse rejection that matches a suite of separation technologies to ore specific characteristics and compares the net value of rejecting low value components in current feed streams with existing mine plans as part of a system-view.

Grade Engineering makes it possible to more efficiently treat lower grade ores and waste to extract valuable minerals, significantly increasing the life of mines and reducing their environmental footprint.

Achievable outcomes for mines, when deploying Grade Engineering at production scale, include significantly improved return on investment and lower capital intensity, according to CRC ORE.

BHP recently engaged CRC ORE and the Grade Engineering solution at its Olympic Dam mine, in South Australia, a location where the mine is actively examining bulk ore sensing and sorting opportunities.

“As Hatch adopts Grade Engineering and extends its reach into the mining industry, the value of such outcomes will increase for operations, clients and communities globally,” it added.

CRC ORE Chief Executive Officer, Dr Ben Adair (pictured signing the agreement on the left), said: “Hatch is a valued a long-term participant in CRC ORE and has actively championed Grade Engineering and its benefits to the industry. As a CRC ORE innovation, we are pleased that Grade Engineering will continue to be delivered by such a capable and engaged team.”

Dr Adair added: “At CRC ORE, our goal has been to develop our solutions to the highest possible standard and then ensure these are then managed by the most capable practitioners to take them to industry. Hatch is the perfect partner to ensure the long-term future of Grade Engineering.”

Under the terms of the commercialisation arrangement, Hatch will use Grade Engineering Intellectual Property for its consulting services.

Hatch Managing Director Australia and Asia, Jan Kwak (pictured signing the agreement on the right), said it was an honour to provide Grade Engineering consulting services.

“Being able to offer Grade Engineering as service is an exciting and positive step forward for Hatch and the mining industry,” Kwak said. “Grade Engineering enables miners to reduce their energy, water and waste signatures while enhancing the productivity and profitability of their operations.

“It also brings us a step closer to our vision for process intensification.”

The Grade Engineering team at Hatch will be headed by Dr Sevda Dehkhoda who has been working closely with CRC ORE since 2019.

“We look forward to continuing the legacy of CRC ORE by enabling the mining industry to intensify operational performance and minimise environmental footprint of the process by refining less waste,” Dr Dehkhoda said. “Adopting Grade Engineering into Hatch’s end-to-end value chain optimisation service offering strengthens Hatch’s position and its commitment to making positive change for mining operations and their communities.”

To facilitate the transition, CRC ORE’s Grade Engineering team will relocate to Hatch’s Brisbane office, supporting Hatch with current and potential users of Grade Engineering.

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

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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.”

ValeOre Metals considering Platsol, Falcon separator, Steinert ore sorting for Pedra Branca

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ValeOre Metals Corp’s Pedra Branca platinum group element (PGE) project, in north-eastern Brazil, looks increasingly like leveraging the Platsol™ high temperature pressure leaching process judging by the latest test work.

Metallurgical results from sample material collected from outcrops at the Trapia and Curiu deposits areas at Pedra Branca for two preliminary Platsol tests conducted at SGS Lakefield, Ontario, have shown recoveries of 93.4-93.6% for palladium and 95.3-95.7% for platinum were achieved.

The company now plans two additional Platsol tests, to be performed by SGS, to determine the effects of adding elemental sulphur to the autoclave to optimise conditions required for PGE and gold recoveries, it said.

Platsol is a high temperature (>200°C) pressure leaching process designed to recover PGEs, gold and base metals. It has been shown to be particularly effective with PGE ore feeds characterised by high concentrations of chromium and low concentrations of sulphide, much like Pedra Branca, according to ValeOre Metals. The PGEs and gold are solubilised as chloro-complexes by the addition of chloride salt to the autoclave, while base metal sulphides are oxidised to form soluble metal sulphate complexes. The precious metals can be recovered directly from the autoclave discharge slurry by carbon absorption, or by precipitation with sulphide ions.

Platsol consists of standard, proven traditional technologies that are in use in mines around the world, according to the company.

The Platsol tests are part of a comprehensive mineralogical evaluation ongoing at SGS to characterise the speciation of palladium and platinum in Pedra Branca mineralisation to guide future process optimisation initiatives.

As part of this, the company is continuing with Falcon Ultrafine gravity separation test work as a potential pre-concentration circuit to upgrade feed material and improve mass pull.

The company has also initiated hot cyanide leach test work to assess the recovery rates of palladium, platinum and gold in a cyanide leaching process, and will shortly commence shipment of 100 representative chip samples from historic drilling at the Esbarro deposit to Steinert’s facility in Minas Gerais, to evaluate the potential of sensor-based ore sorting test work.

ValOre’s Chairman and CEO, Jim Paterson, said: “The pace of success at Pedra Branca has increased dramatically in the last three months, including today’s release of PGE metallurgical recovery rates of in excess of 93% for palladium and 95% for platinum using the Platsol process.

“Together with an aggressive property-wide exploration program, we are now focused on rapidly optimising the conditions, procedures and processes to further maximise the upside potential of the Pedra Branca project.”