Tag Archives: tailings

Jord International addresses pressing issues for BMA Caval Ridge

Jord International has recently taken up a challenge from BHP to come up with a safer solution to filter press maintenance at the Caval Ridge metallurgical coal mine, in Queensland, Australia, as part of the New South Wales-based company’s expanding remit to unlock new technologies for the wider mining industry.

The plant and systems designer, developer and service provider was awarded the project, part of BHP’s Supplier Innovation Program challenge, earlier this year. It has seen Jord design and construct the first concept prototype in tandem with the maintenance team at the mine.

The prototype comprised a belt cartridge installer within a self-contained steel frame that holds a new belt and removes the old, damaged belt. The first commercial belt installer is expected to be in use by July, according to BMA.

Craig Samuel, Jord’s Mechanical Engineer for Aftermarket and Reliability, said the filters the company worked with at BMA Caval Ridge are 3 m wide x 5 m long, with the product path through the filter around 14 m long. While the solution was designed for Caval Ridge specifically, he said it could have applications on any site or with any commodity using filter presses.

“The idea came from the understanding of how the filter belts are installed, and a cartridge-style installer just made sense considering Caval Ridge has a readily available crane to move the cartridge around,” Samuel told IM. “The mechanics of the installer required some out-of-the-box ideas to develop a continuously variable speed ratio between the new belt roll and the old belt roll.”

Samuel said he expected the belt change time to be cut in half with this new solution.

Jord has already applied for another BHP Supplier Innovation Program challenge that could leverage a dust management and cleaning innovation, but the company has also been investing in research and development to commercialise new minerals beneficiation technologies for more efficient and effective liberation of ore, according to Kevin Barber, Jord’s General Manager of Resources.

“Our goal is to unlock new technologies that provide step-change improvements to current processes in the industry,” he said of these new technologies. “It’s about using less energy, using less water and removing some of the environmental challenges with particular focus on tailings. We’re finding alternative ways of dealing with problematic ores and resources.”

Barrick Gold advances emissions reductions targets after a year of ESG positives in 2020

Barrick Gold has decided to up the ESG ante with a new emissions reduction target to 2030 that makes its goal of reaching net zero emissions by 2050 that much more achievable.

The company said its ESG strategy delivered tangible results in 2020, included zero Class 1 environmental incidents, a new record of 79% water recycling and re-use by its operations, and the introduction of fully functional community development committees at all its operating sites to guide its social investment programs.

Speaking in a virtual presentation on sustainability this week, Barrick President and CEO, Mark Bristow, said: “At the beginning of last year, we set an emissions reduction target of 10% by 2030 against a 2018 baseline that combined the data from the legacy Barrick and Randgold operations as well as newly acquired assets. Through the year, we worked on identifying further reduction opportunities and this has enabled us to set an updated target of at least 30% by 2030 with an interim reduction target of 15% based on projects already being implemented, while maintaining a steady production profile.”

He added: “Ultimately our aim is to achieve net zero emissions by 2050, achieved primarily through greenhouse gas reductions and offsets for some hard-to-abate emissions,” he said.

Sustainability has long been a strategic business priority for the company, according to Bristow.

“Our strategy is based on four pillars: the creation of economic benefits for all stakeholders; the protection of health and safety at our mines and in their host communities; a respect for human rights; and the minimisation of our environmental impacts. For us, ESG is not a corporate compliance function: it’s integral to how we manage our businesses worldwide.”

In the same presentation, Barrick’s Group Sustainability Executive, Grant Beringer, said all the company’s sites had been certified to the ISO 14001:2015 environmental management standard. Each site had also been empowered to manage its own environmental issues under the oversight of the group’s strategic leadership. There was a particularly rigorous approach to management of tailings facilities, the company added.

Beringer said: “Our tailings and heap leach management standard has been aligned with the recently updated guidelines of the International Council on Mining and Metals, of which Barrick is a member, as well as those of the Mining Association of Canada. The standard sets out six levels of inspection and surety for the safe operation of tailings and heap leach facilities.”

Sedgman books tailings dewatering work at QCoal’s Byerwen coal mine

CIMIC Group’s minerals processing company, Sedgman, has been awarded a contract to design and construct a tailings dewatering facility at QCoal’s Byerwen coal mine in central Queensland, Australia.

The project will result in a lower operational risk profile, less power usage, and improved water recovery and management of dewatering chemicals, Sedgman says.

Sedgman Managing Director, Grant Fraser, said: “We are pleased to continue working with QCoal with a key focus on reducing impacts and undertaking environmentally responsible practices. The tailings dewatering contract at Byerwen is a great opportunity to achieve joint goals in ESG, an important focus for the industry.”

Construction work for the Byerwen mine will commence this month and the project will conclude in mid-2022.

Back in October, Sedgman was awarded two contract extensions by QCoal to continue to operate and maintain its Sonoma and Byerwen mines processing plants in Queensland.

Second Cat 994K wheel loader arrives at Capstone’s Pinto Valley in latest innovation push

Capstone Mining has brought a second Caterpillar 994K wheel loader to its Pinto Valley operation in Arizona, USA, as it looks to reduce its emissions and improve its operating cost base at the copper mine.

Last year, the mine added to its fleet a Cat 994K loader, which, the company says, burns circa-30 less gallons of fuel per hour (1.9 litres/min) than its current shovels. “This reduced our CO2 emissions and operational cost savings on approximately 116,000 gallons of fuel in 2020,” Capstone said.

The second 994K, added last week, will, in partnership with the first wheel loader, displace around 10,000 shovel hours a year and save approximately 410,000 gallons of fuel and millions in maintenance costs, the company claimed.

Capstone concluded: “Pinto Valley is innovating and optimising for exciting times ahead.”

This is not the only area of innovation the company is currently pursuing at Pinto Valley, an operation it acquired from BHP back in in October 2013.

In its 2020 results, released last month, Capstone said the implementation of phase one of its PV3 Optimization project at Pinto Valley had delivered a 10% sustainable throughput improvement compared with 2019.

The PV3 Optimization project has been designed to achieve safer, more reliable and higher capacity operations without major investments in new comminution equipment. It is doing this by leveraging new inexpensive technologies.

Phase one work, which included improved blast fragmentation processes, installation of a new secondary crusher and screen decks as well as a new mill shell, was completed last year. This saw the mine achieve throughput of 57,168 t/d in the December quarter, 10% higher than the annual 2019 average of 51,137 t/d. December 2020 mill throughput achieved 60,717 t/d, which represents a new monthly record in the mine’s operating history.

Phase two of the PV3 Optimization project is expected to be completed in the second half of 2021, upon completion of upgrades to a conveyor, mill auto controls, cyclone packs and retrofits to the thickeners, it said.

During the month of December, the company conducted a pilot plant test of Eriez HydroFloat coarse particle technology at Pinto Valley, with Capstone saying the results had surpassed expectations of a 6% improvement target to overall copper recovery. In fact, the tests showed a 6-8% increase in overall copper recovery was achievable, which, when combined with expected higher throughput rates, could result in an additional 9-12 MIb/y (4,082-5,443 t/y) of copper production at the operation, it said.

“Additional benefits to the technology include allowing the operation increased throughput by operating at a coarser grind size, which is expected to lower power costs, improve water consumption and lead to improved stability in the tailings storage facility,” Capstone said in its 2020 results. “The estimated $70 million expansionary capital, which includes the installation of Eriez HydroFloat and related equipment, if approved by the board of directors, is expected to be spread over half two 2021 and early 2022, with start-up expected in Q2 (June quarter) 2022.”

Capstone said it expects to release an updated NI 43-101 technical report that encompasses the PV3 Optimization Phase 1 and Phase 2 projects and improvements in the second half of 2021.

At the same time, it is also looking into a PV4 study at Pinto Valley.

Capstone explained: “Feasibility work on scenarios to take advantage of approximately one billion tonnes of mineral resource not currently in the mineral reserve mine plan, which is at similar grade to the current mineral reserves, will be conducted for Pinto Valley.”

The PV4 study is expected to be released in late 2022 and will contemplate using existing mill infrastructure rather than building new facilities, with higher mining rates, higher cutoff grades to the mill and increased tonnage available for leaching.

Extensive column leach test work in collaboration with Jetti Resources LLC will take place over 2021. Jetti’s patented catalytic technology, designed to allow for the efficient and effective heap and stockpile leach extraction of copper, has been a success at Pinto Valley’s leaching operation, where it expects to recover up to 350 million pounds of cathode copper over the next two decades from historic and new mineralised waste piles.

“Capstone is a pioneer in the application of this leach technology and we intend to use it to enhance the economics of a future expansion at Pinto Valley,” it said.

Euro Sun Mining plots Rovina Valley gold-copper production route in DFS

Euro Sun Mining’s definitive feasibility study (DFS) on the Rovina Valley gold and copper project in Romania has outlined the development of two open-pit mines for a 21,000 t/d operation producing 132,000 oz of gold-equivalent over a 16.8-year mine life.

The company plans to use a phased development approach at Rovina Valley, with the development of the two open pit gold-copper deposits, Colnic and Rovina, included in the DFS and the exploitation of the Ciresata underground deposit (not included in the study) phased in following completion of open-pit mining. Ciresata is envisioned as a bulk underground mining operation and will be evaluated for its economic potential in a later study, the company added.

Estimated initial capital expenditure came in at $399 million (including $12.7 million in pre-strip), with average all-in sustaining costs of $813/oz of gold-equivalent. Using $1,550/oz gold and $3.30/lb copper prices, the post-tax net present value (5% discount) came in at $359 million.

These results were broadly in line with a May 2020 target of outlining a DFS with an 18-year mine life, with initial capital expenditure in line with the preliminary economic assessment – which showed off a capital expenditure bill of $339.7 million.

The Rovina Valley project is planned to be mined with a standard open-pit mining method using articulated trucks and a hydraulic loader. The open-pit mining operation is anticipated to last around 16.5 years, during which the lower-grade material will be stockpiled on a pad close to the primary crusher location for treatment over another 18 months. The DFS incorporates simple flotation without the use of cyanide and dry-stack tailings, the company said.

On the latter, the company said: “KCB have designed a waste management facility within the project area for the co-deposition of waste rock and filtered rougher tailings. Process plant rougher tailings will be filtered in the plant where the resultant filter cake will be transported by conveyors and will be co-mingled with waste rock prior to deposition. The cleaner tails will be filtered separately from the rougher tailings and the resultant filter cake will be transported by conveyors and deposited separately within a lined zone contained within the boundary of the co-mingled facility and will be stored separately in a lined zone of the waste management facility.”

Euro Sun said the design had been engineered to reduce the risk of development of impacted seepage from potentially acid-generating waste rock and capture the impacted seepage from the cleaner tailings.

“After completion of mining the Colnic pit, the waste rock and rougher tailings will be preferentially backfilled into the Colnic pit, while the cleaner tails will continue to report to the lined zone of the waste management facility,” it added.

The company said it is targeting first production from Rovina Valley in 2024.

Anglo’s Quellaveco to receive the coarse particle recovery treatment

Anglo American has approved the construction of a coarse particle recovery (CPR) plant at its in-development Quellaveco copper project in Peru.

The announcement came within the company’s 2020 financial results, which showed Anglo generated underlying EBITDA of $9.8 billion and a profit attributable to equity shareholders of $2.1 billion for the year.

CPR, Anglo says, is one of many significant breakthrough technology initiatives that has the potential to increase throughput and productivity, while simultaneously reducing environmental footprint, through rejection of coarse gangue (near-worthless waste material), dry stacking of sand waste, minimising the production of traditional tailings and reducing overall water consumption.

The CPR plant signoff at Quellaveco follows a full-scale demo plant installation at the company’s El Soldado mine in Chile – which is ramping up to full capacity by mid-2021 – and the decision to construct a full-scale system at the Mogalakwena North PGM concentrator in South Africa.

The El Soldado plant used the HydroFloat™ CPR technology from Eriez’s Flotation Division. Here, a single 5 m diameter HydroFloat cell, the largest in the world, treats 100% of mill throughput, with the objective of proving the waste rejection process at full scale.

Anglo said of the Quellaveco CPR plant: “This breakthrough technology will initially allow retreatment of coarse particles from flotation tailings to improve recoveries by circa-3% on average over the life of the mine. This investment will also enable future throughput expansion which will bring a reduction in energy and water consumption per unit of production.”

The capital expenditure of the CPR project is around $130 million, with commissioning of the new plant expected in 2022. DRA Global previously carried out a feasibility study for the CPR plant at Quellaveco.

In terms of Quellaveco project progress, Anglo said today that, despite the COVID-19-related slowdown, first production was still expected in 2022. This was, in part, due to the excellent progress achieved prior to the national lockdown, and based on optimised construction and commissioning plans, Anglo said.

Key activities in 2021 include the start of pre-stripping, which will see the first greenfield use of automated hauling technology in Peru; progressing construction of the primary crusher and ore transport conveyor tunnel to the plant; completion of the 95 km freshwater pipeline that will deliver water from the water source area to the Quellaveco site; completing installation of the shells and motors for both milling lines; and completion of the tailings starter dam.

The mine, owned 60% by Anglo and 40% by Mitsubishi Corp, comes with a production blueprint of 300,000 t/y over the first 10 years of the mine.

Anglo American Platinum’s modernisation drive to continue into 2021

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.

Heritage Minerals smashes Dando Terrier percussive drilling depth record

The Heritage Minerals team, led by Drilling Manager, Shane Charlton, has been achieving depths of 46 m with high-quality 86 mm samples using Dando Drilling’s Terrier percussive drill rig, the drilling manufacturer says.

The depth is a record for the Terrier rig, according to Dando.

Heritage Minerals is currently working on the historied Mount Morgan mine in Queensland, Australia. One of Australia’s oldest mines, Mount Morgan was active from 1882 through to the 1980s. In the process, tens of millions of tonnes of tailings were generated.

Today, these tailings present both a problem and an opportunity; a problem because they were subject to old, polluting technologies for processing gold, but an opportunity because they still contain reserves of gold, copper and other minerals.

Heritage Minerals is employing innovative processing technologies such as ReCYN, developed by partner GreenGold Engineering, to clean pollutants from the tailings and returning them to safe land.

It was this technology and the tailings recovery aim IM recently focused on for an in-depth article on Mount Morgan.

Heritage chose a Dando Terrier rig to sample the tailings at Mount Morgan for several reasons, Dando said.

“Foremost, the unconsolidated geology of tailing fines is very hard to sample with conventional rotary equipment,” it said. “The Terrier’s Duplex Sampling System, which is driven into the ground by a 64 kg anvil and simultaneously cases-off and samples, provides excellent recovery in this type of unconsolidated geology for metallurgical and in-situ density measurements.”

Charlton proved and refined the drilling method he used in the mineral sands of Kalimantan, Indonesia, where he sampled alluvials to over 20 m for lab analysis, Dando says. This is an impressive feat for a rig that has a large user base for geotechnical sampling, standard penetration testing and dynamic probe testing, most often at depths of less than 15 m.

More than doubling this to 45 m was no easy task, Charlton explained: “At depth, it took almost 10 minutes to trip the drive rods and retrieve the sample, but the quality of the sample and the economies in terms of cost per metre offset the sometimes slow drilling.”

Heritage has recently purchased a second Terrier rig from a Dando customer in Australia and Charlton has made some modifications to the design to facilitate drilling beyond the original specifications of the rig.

“We’ve fitted a permanent casing extractor to help pull sample tubes and casing if they get stuck, as well as modifications to assist with tripping rods more quickly,” he said.

To achieve these depths, the team are using a reaming method whereby they sample using an 86 mm windowless sampler tube, and then ream out using a larger 116 mm tube before returning to the 86 mm sampler to continue. This reduces frictional forces along the side of the borehole and abrasive tailing materials, according to Dando.

The percussive hammer system allows sampling without flush, minimising the need for cumbersome mud tanks or air compressors while preventing contamination of the sample or the environment, it added.

Nouveau Monde receives provincial green light for Matawinie graphite mine build

Following a rigorous environmental review, the Québec Government has issued a ministerial decree authorising Nouveau Monde Graphite Inc’s Matawinie mining project for a 100,000 t/y high-purity graphite concentrate production.

Located only 150 km north of Montréal, the company’s deposit constitutes the largest projected graphite operation in North America and Europe and is expected to become the world’s first all-electric open-pit mine, Nouveau Monde says.

“Since filing its bankable feasibility study, Nouveau Monde has invested time and effort to meticulously plan mining and environmental engineering, master the ore metallurgical process to reach 97% purity after simple flotation, de-risk its operation through its demonstration plant, and actively engage with the local community of St-Michel-des-Saints to secure a social licence to operate and with the Atikamekw First Nation,” the company said.

The environmental decree now provides Nouveau Monde with the operational criteria and final design parameters to launch construction activities.

It plans to start early works at the mining site as of the June quarter, and full construction is expected to be launched in the September quarter once permits and authorisations are finalised. The project timeline places commissioning activities and start-up of commercial production in 2023.

Arne H Frandsen, Chairman of Nouveau Monde, said: “Today’s milestone is something we have worked towards as a team since the outset in 2011. After a decade of meticulous planning, we can now commence the mine construction of our world-class Matawinie graphite project. We are most grateful for the continued support Nouveau Monde has received from the Québec Government and our partnership with Investissement Québec as well as the backing from our local host communities – all being important stakeholders of this success.

“We will exercise our mandate in the spirit of cooperation, sustainability and benefit sharing for all parties involved. The creation of the Western World’s largest anode-quality graphite mine will assist positioning Québec as the prime location for the North American battery materials hub – supplying the continent with the critical anode and cathode materials required for the batteries needed for the global electrification of mobility.”

Eric Desaulniers, President and CEO of Nouveau Monde, added: “With this green light to launch our Matawinie project, we plan to bring to market a responsibly extracted high-purity graphite to supply electric vehicles and energy storage sectors with a local and sustainable alternative. Doing so will position Nouveau Monde as a leading anode material provider for decades to come, creating opportunities and unlocking value for all parties involved.”

Nouveau Monde is working towards developing an operation that can provide the volumes required by major auto original equipment manufacturers and battery manufacturers; the most recent estimates indicate 120.3 Mt combined measured and indicated resources at a 4.26% Cg grade. Geological knowledge of the Matawinie property, paired with experience in extracting and concentrating the ore at the company’s demonstration plant, have significantly de-risked the project.

Nouveau Monde has also integrated forward looking and innovative environmental initiatives to limit the project’s footprint and protect local biodiversity, namely:

  • Integrated onsite water management system guaranteeing constant monitoring and treatment that meet the highest quality standards;
  • Co-disposal of tailings and waste rock in line with requirements of the best practices such as The Global Tailings Review, the International Network for Acid Prevention and the Canadian Mine Environment Neutral Drainage Program. This management solution helps avoid acid mine drainage, provides greater environmental safety in the long term and reduces the infrastructure’s footprint;
  • Progressive land reclamation through backfilling of the pit and a comprehensive restoration plan; and
  • An all-electric fleet – a world’s first for an open-pit mine – powered by Québec’s clean, abundant, and affordable hydroelectricity.

Through its demonstration operations, Nouveau Monde has already validated its process for desulphurisation of tailings and completed the construction of a co-disposal experimental cell through a collaborative partnership with Université du Québec en Abitibi-Témiscamingue.

Over the life of mine, the company intends to implement this system through a co-disposal pile and backfilling of the pit as of year six, promoting thereby the restoration of the natural ecosystem while reducing environmental risks. To ensure long-term sustainability, the co-disposal storage facility will also include a capillary barrier effect multi-layer cover to block oxygen and vegetate the site.

SNC-Lavalin, Lamont Expert, Minesite Drainage Assessment Group and the National Research Council (NRC) of Canada have conducted modelling analysis of Nouveau Monde’s co-disposal design to study critical design parameters on sulphide oxidation reaction rates and optimise configurations of the pit backfill and co-disposal pile.

Recently the company has expanded the mandate of NRC to simulate additional site-specific pile design parameters, like compaction level, using Nouveau Monde’s demonstration plant tailings and test cell results. NRC will expand the model developed in earlier phases and provide the company with a strong tool to optimise tailings deposition plans.

Newlox heralds the potential of OAR gold leaching technology following test work

Newlox Gold Ventures Corp’s affiliate has reported what it says are “excellent results” from Stage 1 testing of the new Organic Aqua Regia (OAR) gold leaching technology on high-grade gold ore samples.

Newlox Research and Development Corp’s final analysis of the results from Stage 1 testing indicated not only is a gold recovery of 94.68% achieved at ambient temperature, but also a 100% recovery is achieved at 80°C.

The company is investigating the use of OAR technology as a non-toxic and water-free alternative to cyanidation to produce both gold and other precious metals. This will benefit Newlox Gold Ventures Corp’s ambition to recover residual precious metals and contaminants from historical tailings.

Newlox R&D is developing OAR in conjunction with the University of British Columbia in Canada and Chiba University in Japan to leach gold with this reagent, which is both non-toxic and widely used in other industries, according to the company. The main advantages include that it is non-toxic, is recyclable, extracts gold faster than cyanide, does not use water, and does not require carbon or electrowinning.

The company undertook Stage 1 testing on a high-grade gold ore grading an average of 48.87 g/t. The ore was ground in a BICO mill to reach a point where 80% of the material was below a grain size of 0.12 mm (P80 -0.12 mm) before leaching with OAR. Newlox’s research team used the Yates model in 16 experiments to investigate several combinations of reagent dosage and leaching time, it said.

Newlox R&D Corp undertook leaching tests in Vancouver, with the gold dissolution in the OAR calculated based on the gold grade in residues obtained after filtration. A third-party metallurgical laboratory (Global Mineral Resources) in Burnaby, British Columbia, was used to verify the results using aqua regia digestion and Atomic Absorption Spectroscopy (AAS).

The company explained: “The R&D team used the Yates testing protocol to modify various factors during testing and evaluate their effects and relevant interactions. The Yates protocol identified the most significant factors in overall gold recovery. Most encouragingly was the feature that all samples returning over 90% recovery during Stage 1 testing had reagent dosage commonalities, indicating a clear route forward for Stage 2 testing.”

Parallel testing was undertaken at the University of Chiba in Japan on the same ores tested by Newlox R&D in Vancouver. The Japan-based team experimented with alternative reagent additives and different leaching temperatures and found significant effects based on those factors.

Leaching tests undertaken in Japan at 80°C achieved 100% gold recovery in four hours, followed by precipitation of the dissolved gold by adjusting the solution’s pH. The pH control enabled pure gold recovery while concurrently suppressing the precipitation of other elements in the precipitate.

“This promising result indicates that gold may be recovered from the solution without the need for electrowinning,” the company said.

Stage 2 testing is now underway to both reproduce the results seen in Stage 1 testing and further investigate the effect of reagent dosage, time, and temperature on leaching mechanics. Additionally, the R&D team is focused on testing both the recyclability of the OAR reagent, and methods for recovering gold from the solution.

Ryan Jackson, President & CEO of Newlox, said: “We are most encouraged to report that the first round of testing achieved up to 100% gold recovery, using the cutting-edge OAR leaching technology. This initial round of testing forms part of the Newlox R&D 12-month OAR development program.

“We are gratified to realise such early positive results. OAR leaching promises to become a paradigm-shifting technology applicable not only to the $180 billion formal global gold mining industry but also as a method to bring the $27 billion informal gold mining industry into the 21st century.”