Tag Archives: IGO

Think & Act Differently Cohort set to revolutionise in-situ recovery

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The Think & Act Differently (TAD) incubator, powered by BHP, has announced its support for a new cohort that has come together to develop an innovative technology roadmap for in-situ and alternative extraction options, the company says, lower the impact of mining and processing.

In collaboration with its partner, Unearthed, the TAD Cohort was curated through a venture-style selection process, which also involved selection of members from the TAD Ecosystem.

This cohort is supported and funded by BHP, Boliden, Rio Tinto, South32 and IGO, as part of the TAD Collaboration that is commited to unlocking new technologies and reimagining lower impact mining and processing to find value in overlooked resources.

The TAD Cohort comprises a diverse group of companies ready to apply new ways of thinking to in-situ recovery. It includes:

  • Auric BioRecovery: using bio recovery processes to release metal from tailings;
  • Clean & Recover: ElectroClear recovery of water from acid mine drainage;
  • Destiny Copper: Using high activation potential and chemistry to eliminate electricity requirements for plating copper;
  • Draslovka: A ‘green’ recyclable lixiviant, selective in leaching base and precious metals from host minerals (pictured in a test lab above);
  • Eden GeoPower: Rock preconditioning technology to enable in-situ solution mining;
  • Ekion: Enabling the in-situ extraction of metals using electrokinetics;
  • EnviroGold Global: Clean-technology process for metal recovery from sulphide mine tailings and smelter residues; metal recovery includes strategic, critical, base and precious metals;
  • LeadFX: Metal recovery with CO2 capture;
  • Loop Hydrometallurgy: Clean technology unlocking copper, rare earth elements and other metals from tailings and concentrates;
  • Muon Vision: Cosmic ray sensing for tailings and heap leach monitoring; and
  • Precision Periodic: Enabling industrial scale chromatography using novel filtration media to recover and concentrate elements in mining applications and treatment of wastewater.

Barminco wins extended stay at IGO’s Flying Fox nickel mine

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Perenti says its Barminco subsidiary has been awarded a nine-month contract extension at the Flying Fox mine, in Western Australia, owned and operated by IGO Ltd.

The contract extension is effective from January 1, 2023, and has a value of approximately A$30 million ($20.2 million) over the nine-month term.

Mark Norwell, Managing Director & CEO of Perenti, said: “In Australia, the labour market is still tight, and inflation and cost escalation remains stubbornly persistent, however strong and collaborative working relationships, like the relationship between IGO and Barminco, are key to the success of our business as well as the success of our clients. By working collaboratively with our clients, we continue to navigate and manage challenging macro-economic conditions.”

Paul Muller, President of Perenti Contract Mining, added: “We have a very long and proud history of operating within the Forrestania Operation and we are pleased to have delivered value and certainty at the Flying Fox mine from a greenfield development project through to a mature operating mine as it is today. We look forward to continuing our relationship with IGO, our largest client in Australia.”

IGO became the owner of the Flying Fox mine, part of the Forrestania Operation, in 2022, as part of the acquisition of Western Areas. It remains one of the highest grade nickel mines in the world. Production commenced in 2006, and the mine now operates at depths of over 1 km underground.

ZERO Automotive brings newest ZED70 Ti BEV to IGO’s Nova project

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ZERO Automotive has delivered what it refers to as an ultra-safe ZED70 Ti battery-electric converted utility vehicle, using LTO battery technology that does not suffer from thermal runaway, to Independence Group’s Nova nickel-copper-cobalt operation in Western Australia.

This is the second convered vehicle, and the first dual cab, for Barminco, the contractor at Nova.

Like the first delivery, this conversion also allows for ultra-fast charging and maintains the highest torque rating for a mining-spec battery-electric vehicle by a factor of one-and-a-half times, the company says. Site integration activities with charging infrastructure and data capture will be the focus in the coming months, with the installation of the Geotab GO9 telematic device allowing for vehicle monitoring and tracking.

This is the third vehicle delivered with METS Ignited support previously awarded to ZERO Automotive. It also forms part of the trials being undertaken by Barminco in its role as lead of the Electric Mine Consortium light and auxiliary vehicle working group, of which ZERO Automotive is also a participant.

The next conversion for Barminco will be its upgraded production platform, which will provide available torque of 267% greater than its closest competitor, and allows for faster charging, ZERO Automotive says.

Miners need to address workplace culture, diversity issues, IMARC panel says

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There has been keen focus on workplace culture and diversity on the final day of the International Mining and Resources Conference (IMARC) in Sydney, Australia.

Throughout the conference, mining leaders have acknowledged that if the industry does not act now to fix and change the culture, they will not be able to attract the staff required for the new resources boom.

Chief People Office at IGO, Sam Retallack, told the conference: “We as industry have broken the psychological contract of trust that we have with the community. We are seen as a cause of climate change, not as a solution. We are seen as an unsafe workplace for females, we are seen as inflexible with our rostering and that you must commit to FIFO work. It’s not a particularly attractive proposition for new workers.”

Danielle Martin, Director of Social Performance at ICMM, spoke to the substantial issues facing the industry as workforce skills change and evolve.

“The competition for talent will be tricky for mining because the skills in many cases are less specific to mining and are applicable across other sectors,” Martin said. “Because of the culture and perception of mining, it is a less attractive industry for many workers who could work in other industries.”

All is not lost, however. Stuart Jenner, General Manager of Capability and Culture at Gold Road Resources, reflected on the cultural issues the Australian Defence Force faced 20 years ago. Changes to workplace culture will likely lead to an increase in the recruitment of new staff and the retention of key talent as the competition for skills intensifies, he argued.

Jenner said the Defence Force “recreated its brand and aligned it with its purpose and mining needs to do the same”.

He added: “We need to be upfront, honest and transparent to establish that purpose. The Defence Force pays nowhere near what the mining industry does but because of their purpose, they have a huge amount of success in attracting talent.”

There is a realisation from the sector the industry must act now and push for the acknowledgment that these issues need to be addressed from the top down.

Gavin Wood, Chief Information Officer at Newcrest Mining, explained to the delegates at IMARC the work the company is doing to change culture with their existing workforce.

Wood said many of its existing staff grew up in mining areas and communities and the company needed to give them the skills to interact with other aspects of business and by virtue society.

“If we do not give them these skills the culture will not change,” he said.

Over the three-day conference, mining leaders from across the globe have challenged the current standard of culture within the sector and have discussed ways to make the industry safer for all.

GR Engineering bolsters EPC scope at IGO’s Cosmos nickel operations

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GR Engineering Services says it has increased the scope of work related to the engineering, procurement and construction contract with Australian Nickel Investments Pty Ltd, a wholly owned subsidiary of IGO Limited, for the upgrade of the existing nickel concentrator at the Cosmos nickel operations, in Western Australia.

The company has been awarded a variation by IGO to further increase the throughput of the nickel concentrator at the project from circa-750,000 t/y to 1.1 Mt/y. This will bring the contract sum to A$76 million ($49 million), it said.

Geoff Jones, GR Engineering Managing Director, said: “GR Engineering has a long history of working with the IGO management team and is pleased to be awarded with this variation. GR Engineering looks forward to safely and successfully completing this important project.”

IGO’s CEO, Matt Dusci, added: “IGO is pleased to be working with GR Engineering on the Cosmos project after the previous successful collaboration on Nova.”

Following the acquisition of Western Areas Limited on June 20, 2022, IGO commenced work toward developing a project optimisation strategy and plan designed to deliver higher production rates for the life of the operation and a more safe and sustainable mine plan at Cosmos. The increased plant throughput strategy was part of this.

IGO is currently developing the Odysseus underground mine at Cosmos, with plans to deliver high quality nickel concentrates into the global market.

Zero Automotive overcoming barriers with BEV conversion offering

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Zero Automotive is one of several Australia-based companies looking to supply the clean and green light utility vehicles the domestic hard-rock sector requires over the next decades to achieve crucial sustainability goals while retaining high productivity levels.

Thanks to the support of a significant copper-gold miner in Australia, its membership of the Electric Mine Consortium (EMC) and METS Ignited backing, the company finds itself in a strong position to deliver these machines against a backdrop of supply chain issues and ever-evolving safety and regulatory requirements.

“We’ve got commitments for six machines altogether and are in the process of offering our production version to the market,” Dan Taylor, Business Development Manager for Zero Automotive, says.

The first and second units are already running at OZ Minerals’ Carrapateena copper-gold mine in South Australia – Zero Automotive’s home state.

The first machine – a ZED70 Ti™ battery-electric light vehicle – was originally delivered to the mine at the back end of 2020 for testing. After successful trials, the company acquired this unit outright and, in early-2022, added a second Zero Automotive ZED70 Ti to enable its workforce to familiarise themselves with the capabilities and charging methodology that come with electric light utility vehicles.

Since then, the company has delivered a third ZED70 Ti conversion to Barminco, which is now on site at its client IGO Ltd’s Nova nickel-copper-cobalt operation in Western Australia. This vehicle is the first single cab conversion developed by Zero Automotive and will be deployed to site foremen to allow the mining contractor to gain a good understanding of its capabilities.

All three of these machines – and the three to follow – are based off battery-electric conversions of the Toyota LandCruiser 79 Series, a vehicle that has been part of the Australian mining landscape for many years.

The modular nature of the Zero Automotive platform enables its long-life battery energy system to be reused in multiple chassis, lowering the total lifecycle cost of the fleet as well as the cost of Scope 1 emissions, according to the company.

They also include dual AC-DC charging with the CCS Combo2 connection, which is becoming increasingly standardised in the mining space.

Data and feedback from the second OZ Minerals machine and the initial Barminco vehicle will be fed back into the EMC ecosystem under the Light and Auxiliary Equipment Working Group as part of the consortium’s continual improvement and knowledge sharing remit.

The EMC said of the consortium’s ongoing light and auxiliary equipment electrification ambitions: “Converting light and auxiliary vehicles as rapidly as possible to electric is key to the industry building the broader understanding and familiarity with electric equipment and infrastructure that will accelerate adoption across all aspects of operations.”

The EMC is a growing group of over 20 mining and service companies driven by the imperative to produce zero-emission products for their customers and meet mounting investor expectations. The objective of the EMC, backed by METS Ignited, is to accelerate progress toward the zero-carbon and zero-particulate mine.

The following three machines are also expected to be deployed to EMC members, with METS Ignited agreeing to provide some A$400,000 ($297,938) of funding towards the diesel-to-battery conversion projects outside of the vehicles already delivered to OZ Minerals.

“The key thing with all of these vehicle deployments is the ZED70 Ti being able to do the job the miners need to perform safely and reliably, getting the associated charging infrastructure right and working with key stakeholders on the change management process,” Dave Mitchell, founder and CEO of Zero Automotive, says. “Operators also need to get used to the power under the hood and how to maximise the battery re-charging capabilities when going down ramp.

“As a matter of course, we train up and educate the sites about the best way to utilise these vehicles,” he said.

To this point, the two prototype vehicles already operating out at Carrapateena have shown that they can work for a typical shift without requiring a re-charge and can then utilise the battery’s AC/DC-DC fast-charge option during shift changeover to enable another user to run the machine for the following shift.

The use of LTO (Lithium Titanate Oxide) battery chemistry and a 60-kWh battery capacity has been behind this performance. This electric motor can generate continuous power of 75 kW and peak power of 134 kW, plus 358 Nm of continuous torque. These values will be increased to 100 kW, 200 kW and 520 Nm (1,200 Nm peak) for the production version.

To this point, the power dimension has often been the main metric quoted with any battery-electric machine, but Taylor pointed out that safety and regulatory considerations were often the biggest barriers to overcome in terms of getting machines operating at underground mines – a hurdle that Zero Automotive has cleared.

“We were able to successfully commission our second ZED70 Ti for OZ Minerals within two days of the machine arriving on site,” he said. “A lot of people are putting out offerings for light utility vehicles, but the required risk analysis in terms of deploying a vehicle underground has not been successfully worked through. This is rightfully a high bar to clear.

“We address any safety or regulatory considerations during our design process – not when the machine is on site – to make sure that operators can start using them quickly.”

Mitchell adds: “The user case is what we are focused on. That has allowed us to scale our offering quickly and ensure our clients can start running the machine underground as soon as they have it on site.”

Zero Automotive is expecting to deploy the other three machines on its books to the same companies (OZ Minerals and Barminco), but the final two machines of the six to be delivered will be under a revised platform to the original ZED70 Ti.

“It will be a platform that is designed from the ground up that incorporates the desired features and learnings from the first conversions, but we will simplify it to reduce complexity, weight and cost,” Mitchell said. “We’re sticking with the same battery configuration – which has proven itself in terms of power, safety and longevity – but we’re adding some auxiliary power outputs and ensuring the machine is multi-purpose.”

The latter element is tied to the company’s medium-to-long-term ambitions, which include the potential to supply battery-electric machines specific to the extended range space too.

For now, Zero Automotive is focused on getting its machines underground at hard-rock operations, ensuring operators and mining companies start realising the productivity and emission benefits that come with these zero-emission conversions.

Electric Mine Consortium partners with AWS on world-first mine decarbonisation platform

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Australia’s Electric Mine Consortium (EMC), made up of some of the world’s leading mining and service companies, has announced it is working with Amazon Web Services (AWS), an Amazon.com company, to accelerate the electrification of mine sites globally.

Announced at AWS Summit 2022, EMC is using AWS’s depth and breadth of services, including machine learning, business intelligence and storage, to build the world’s first mining data platform, to capture real-time information on mine decarbonisation from sites globally.

To drive decarbonisation, mining companies can use the platform to measure energy storage levels and electrical infrastructure use from global mine sites to accelerate the creation of a cleaner, more electrified future in mining, EMC said.

Co-founder of the EMC, Graeme Stanway, says the platform can help enable EMC members to share sustainability insights and analyse the outcomes of adopting electrified mining infrastructure and sustainable operations.

“The way we generate, store and harness energy around the globe is changing drastically,” Stanway said. “EMC’s collaboration with AWS will help see us at the forefront of this change, driving the mining industry’s electrification at scale.”

Stanway said the industry is crying out for tools to decarbonise due to tightening government emission reduction targets, increasing environmental, social and governance pressure, and the industry being responsible for 7% of the greenhouse gas emissions globally.

“Like the electric vehicle industry, electric mines are the future” Stanway said. “Not only can they be safer through the eradication of diesel particulates, pollution, noise and vibrations, they can also be more targeted, precise and effective when it comes to mining, and yield stronger results than traditional mines with minimal ground disturbance.”

As part of the initiative, EMC created a “data lake” using Amazon Simple Storage Service (Amazon S3), a cloud object storage service, that can securely store thousands of datasets from the consortium’s mines, including data on energy consumption and renewable energy infrastructure output.

EMC can then clean the data and run data pipelines using AWS Step Functions, a low-code, visual workflow service; AWS Glue, a serverless data integration service; and AWS Lambda, a serverless, event-driven compute service. AWS Glue can provide EMC with data catalogue functionality, and AWS Lake Formation, a service that makes it easy to set up a secure data lake in days, can deliver security and access control.

Amazon QuickSight, a business intelligence service (screenshot pictured), can allow everyone in the consortium to explore and understand mining data through user-friendly interactive dashboards that identify efficiency practices that may reduce emissions, according to EMC.

Also, using Amazon SageMaker, a fully managed service to build, train, and deploy machine learning models, EMC can train machine-learning models to predict energy usage spikes at mines and track the carbon efficiency of deploying sustainable energy infrastructure.

Sarah Bassett, Head of Mining and Energy, Australia at AWS, said: “Data capture and analysis is essential to mining operations, and AWS is helping consortium members to share their critical datasets and collective insights to drive the digitisation and evolution of the industry. I am excited to be collaborating with the EMC and its consortium members to improve the design of mines globally and accelerate the industry’s journey to decarbonisation on the global scale.”

The EMC is a growing group of over 20 mining and service companies. These companies are driven by the imperative to produce zero-emission products for their customers and meet mounting investor expectations. Thus, the objective of the EMC is to accelerate progress toward the zero-carbon and zero-particulate mine through:

  • Resolving key technology choices;
  • Shaping the supplier ecosystem;
  • Influencing policy; and
  • Communicating the business case

The EMC is emerging as a key vehicle for the decarbonisation of the mining industry, particularly for underground operations, and will remain responsive to the rapidly changing external environment.

Members include OZ Minerals, Newcrest Mining, Gold Fields, IGO, South32, Blackstone Minerals, Evolution Mining, Barminco and Iluka Resources.

Zenith Energy to roll out 5B Maverick solar system across Australian mine sites

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Renewable energy penetration is set to increase on major mine sites in the Goldfields and Pilbara regions of Australia, after Zenith Energy and 5B signed a deployment agreement that could see the 5B Maverick™ system rolled out.

Zenith, one of Australia’s leading independent power producers, and 5B, a clean energy technology provider, signed an Ecosystem Framework Agreement-Deployment, permitting Zenith to be a deployment partner of the 5B Maverick system within Australia.

The 5B Maverick system solar array is prefabricated, allowing rapid deployment while increasing the ability of Zenith to expand renewable assets across existing and future sites, Zenith said. Each 5B Maverick array consists of up to 90 solar panels, mounted on specially designed racks, and optimised for the 540-550 W module class of the utility scale solar industry.

Zenith Managing Director, Hamish Moffat, said the partnership represents the next step in reducing emissions across Zenith’s legacy portfolio.

“We’ve been looking to increase renewable assets across multiple sites for some time; the question has always been around how we can achieve that in such a way that is economically viable,” he said. “The 5B Maverick system is re-deployable, meaning it can be integrated on mines with shorter tenure, and moved at the end of operations at those sites.”

He added: “It offers Zenith greater ability to leverage value from our initial capital expenditure, making it more cost effective to offer expanded renewable energy solutions for our clients.”

5B Co-Founder and CEO, Chris McGrath, said the strategic partnership is an important validation of 5B Maverick’s ability to reduce deployment complexity.

“This has been a major barrier for solar installations on mine sites worldwide,” he said. “The agreement also shows that our cost reduction efforts over the past two years have worked – we’ve hit the price point where 5B Mavericks can be viably packed up and redeployed elsewhere, substantially reducing the risk of stranded assets in mining, agricultural and industrial operations.”

Moffat said Zenith is looking to integrate the 5B Maverick system across three sites initially. These include:

  • Nova: The 5B Maverick will play a major role in Zenith’s industry first ‘engine-off’ project at IGO’s Nova nickel mine, allowing the site to operate on up to nine consecutive hours of renewable energy through the installation of an extra 10 MW of solar, and a 10 MW battery energy storage system;
  • Warrawoona: Zenith recently committed to the supply, installation, and commissioning of a 4 MW DC Solar Farm, using the 5B Maverick, as well as a 3 MW/3 MWh AC battery energy storage system at Warrawoona, owned by Calidus Resources. The hybrid power station configuration will reduce gas use, which in turn results in a reduction in emissions; and
  • King of The Hills: Work is currently underway to install 2 MW of 5B Maverick on the Red 5 site, also supported by a battery energy storage system.

Moffat said the 5B agreement is another key milestone on the company’s journey toward ‘net zero’.

“Our 2035 ‘net zero’ target strikes a balance between ambition and ability to achieve, with the 5B partnership a clear demonstration of our progress and commitment to this goal,” he said.

McGrath said 5B was keen to partner with Zenith, given the independent power producer’s strong reputation and credibility in providing renewable energy solutions to the mining and resources industry.

“We’re keen to develop mutually beneficial partnerships with like-minded companies, and Zenith definitely fits the bill,” he said. “It is great to see Zenith leveraging the ability of the 5B Maverick solar arrays to deploy up to 10 times faster, more safely than single axis tracker and fixed tilt solar systems, to deliver a full solution for their customers.”

Moffat said the partnership offers both Zenith and 5B the opportunity to continue to lead the industry, demonstrating the ability and capacity to effectively integrate renewable energy solutions.

“We have continually said we want to be part of the renewable solution, not just by developing the concepts needed, but by also actively deploying and proving the technology,” he said. “The partnership with 5B allows us to do this and continue to bring our clients on the glide path to ‘net zero’.”

IGO to trial VSUN Energy’s VRFP energy storage tech at Nova nickel operation

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IGO Limited looks set to test VSUN Energy’s vanadium redox flow battery (VRFB) energy storage technology in a standalone power system (SPS) application at its Nova nickel operation in Western Australia.

An SPS supplies power independently to the electricity grid and typically comprises a combination of solar, wind, battery and backup generation from diesel or gas. The SPS at Nova, supplied by Australian Vanadium Ltd subsidiary VSUN, will power a bore pump with a target of 100% renewable energy use.

The SPS heading to IGO’s nickel operation will be based around a 300 kWh VRFB from Spanish manufacturer E22. The system has been designed to provide a 100% renewable energy supply for much of the year, with periods of long cloud cover being supported by a diesel genset, Australian Vanadium said.

Total renewable penetration of 85-90% is being targeted for the trial of the VRFB-based SPS system.

The SPS is redeployable for use on multiple mines sites and locations over its 20-plus year service life, Australian Vanadium said. The target of long periods with “diesel-off” will not only significantly reduce the carbon emissions of diesel generator powered bore fields, but also offer substantial reductions in operating hours for service personnel, according to the company.

“These two significant benefits indicate a potentially rapid growth market segment for this robust technology,” the company said.

Australian Vanadium Managing Director, Vincent Algar, said: “Working with IGO on this project will accelerate the objectives of the companies and broader mining industry towards carbon neutrality. The robustness of VRFB energy storage makes it perfectly suited to the tough environments found on many Australian mine sites.”

He added: “The installation of an SPS based on vanadium technology for pumping applications enables diesel to be almost entirely eliminated, helping reduce overall carbon emissions and providing reliable green power. We look forward to trialling and then duplicating this system based on an Australian invention and with Australian-made vanadium electrolyte from AVL in Western Australia.”

IGO’s Chief Operating Officer, Matt Dusci, said: “IGO’s strategic focus is on those products that are critical to enabling clean energy solutions, to create a better planet. As part of our strategy to deliver those products, we aspire to be carbon neutral across our business and to do this, in part, by leveraging renewable energy solutions and innovation to reduce emissions at our remote exploration and mining operations. We are excited to be collaborating with AVL on this pilot at our Nova operation.”

In July 2021, AVL was awarded a A$3.69 million ($2.69 million) Federal Government manufacturing grant under the Modern Manufacturing Initiative Resources Technology and Critical Minerals Processing National Manufacturing Priority roadmap. Part of the matched funding is allocated to development of the SPS that will be installed at IGO’s Nova nickel operation.

The remainder of the grant will be used to finalise the high purity processing circuit for the Australian Vanadium Project; build and operate a commercial vanadium electrolyte manufacturing plant producing 33 MWh/y and manufacture a prototype of a residential VRFB.

The agreement with IGO will end 12 months from the date of system commissioning and first power production, unless extended or terminated in accordance with the agreement. The SPS is being provided to IGO at no charge, with the option to purchase or rent the system at the end of the trial period. The project will enable IGO to analyse the performance of the SPS for potential use in its dewatering and bore pumps systems.

AngloGold, IGO eye Tropicana production flexibility as Boston Shaker goes commercial

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AngloGold Ashanti, in conjunction with its joint venture partner IGO Ltd, has declared commercial production at the Boston Shaker underground mine at its Tropicana gold operation in Western Australia.

Situated some 330 km east-northeast of Kalgoorlie, the operation is managed by AngloGold Ashanti Australia (AGAA) with a 70% interest, while IGO holds the remaining 30% interest.

Development of the Boston Shaker mine was approved in March 2019, and the mine transitioned into commercial production this month on schedule, below the A$105.7 million ($77 million) budget and, importantly, with no recordable safety incidents, AngloGold said.

Boston Shaker will deliver around 1.1 Mt/y of ore at an estimated grade of 3.5 g/t, contributing some 100,000 oz/y to gold production over a seven-year mine life.

“Underground mining at Boston Shaker will leverage further value from this high performing operation, achieving payback in just over three years with upside potential as the deposit remains open at depth,” AngloGold Ashanti SVP Australia, Michael Erickson, said. “The underground mine will contribute higher-grade mill feed from the current quarter onwards, improving the gold production profile and enhancing cash flow during calendar 2021-2023 when the mine plan includes periods of higher waste stripping in the Havana open pit.”

AngloGold has previously said operational excellence work at the underground mine is focused on remote bogging, the mechanical operator-controlled digging of ore from surface, and on optimising level spacing and extraction ratios.

The first production stope was fired in June 2020 and underground ore production has now reached an annualised production rate of 700,000 t/y with the design production rate expected to be achieved in March 2021.The commercial production milestone at Boston Shaker comes after Tropicana produced its 3 millionth ounce of gold in March this year, just seven years after pouring first gold in September 2013.

AngloGold explained: “From commencement of the operation at Tropicana the mining strategy has been designed to optimise cash flow, net present value and the delivery of ore. The Tropicana, Havana, Havana South and Boston Shaker open pits have been mined as a series of cutbacks, sequenced and scheduled to maximise value at a mining rate that delivers the best mining unit cost for the scale of the operation.”

Up until June 2020, ore production from the open pits exceeded the plant capacity, allowing higher-grade ore to be preferentially treated, while lower grade ore was accumulated on stockpiles. Over the course of the second half of 2019 and first half of 2020, the Tropicana pit and Havana pit were completed, in line with the mine plan. As a result, grade streaming came to an end and stockpiled ore is currently being used to supplement the mill feed from the Havana South and Boston Shaker pits.

A decision was made in the June 2020 quarter to invest in the next cutback of the Havana pit (Stage 2) which will allow access to the deeper Havana open-pit ore from 2022 onwards. While this cutback is being completed, mill feed will be sourced from the Boston Shaker open pit, supplemented by some 4 Mt/y of low grade (0.85-1.05 g/t) stockpiled ore, resulting in a lower milled grade over the period. The lower grade will be partially offset by the Boston Shaker underground mine, which is ramping up and will be contributing at full capacity by the second half of 2021.

The plan remains for gold production (at 100%) in 2020 and 2021 to be between 400,000-450,000 oz, compared with 513,785 oz last year. From 2022 onwards, annual gold production will normalise between 450,000-500,000 oz as the low-grade stockpile ore in the mill feed is displaced by a larger proportion of Boston Shaker underground ore and an increasing contribution of higher-grade ore from the Havana pit, as the cutback progresses.

AngloGold says significant potential remains to unlock known extensions of mineralisation beneath the Tropicana and Havana open pits and the extensions at depth of the Boston Shaker Underground. Development of an underground drill drive from the Boston Shaker Decline is well advanced with a total of 240 m completed to date. The drill drive is well positioned to also provide production access to the Tropicana underground reserve should the drilling prove successful. Underground diamond drilling is scheduled for the December 2020 quarter with a decision to mine expected during 2021.

Final trade-off studies are currently being completed on the Havana Stage 3 open pit cut-back and Havana underground to determine the optimal open pit – underground interface. A decision on the way forward for Havana Stage 3 is expected to be made during 2021.

(photo credit: Macmahon)