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BHP Mitsubishi Alliance secures half of Central Queensland power requirements with renewables

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BHP Mitsubishi Alliance (BMA) has entered into a new renewable power purchase agreement (PPA) with Queensland’s publicly-owned energy generator and retailer CleanCo, which, the company says, is expected to provide half the forecasted electricity demand of BMA’s Central Queensland operations over five years from January 2026.

The new PPA will run to the end of 2030 and effectively extend an existing low carbon emission power agreement between BMA and CleanCo currently running to the end of 2025.

This second PPA will enable BMA to continue to source half of its expected electricity needs from low greenhouse gas emission sources such as solar and wind, as well as pumped hydro.

BHP President Australia, Geraldine Slattery, said: “We are increasing renewable electricity at BMA in line with our decarbonisation commitments to 2030 and beyond, improving the long-term sustainability of our business while at the same time supporting Queensland’s renewable electricity infrastructure build, regional communities and local jobs.

“We expect demand for Queensland’s higher-quality metallurgical coal to remain strong for many years to come, as major steelmakers look to reduce their emissions intensity while delivering the steel needed to support global population growth and decarbonisation infrastructure.”

BHP Chief Commercial Officer, Vandita Pant, said: “Using more renewable electricity at our operated assets across the globe is key to our operational decarbonisation strategy. We are pleased to continue our strong relationship with CleanCo.

“Through a growing number of agreements to supply our mines in Chile, Queensland, Western Australia and South Australia with renewable electricity, we are making good progress on decarbonisation while supporting the development of renewable infrastructure and stimulating regional economies.”

The new PPA will help support four renewable electricity projects across regional Queensland, which combined are expected to generate more than 1,500 local jobs during construction: the Dulacca Wind Farm due for completion in late 2023, the MacIntyre Wind Farm due for completion in 2025, and the Western Downs Green Power Hub and Kaban Wind Farm that currently supply electricity to the grid and are expected to reach full commercial operation later this year.

The PPA is also linked to CleanCo’s new renewable energy storage initiative, which directs excess renewables to the Wivenhoe Pumped Storage Hydroelectric Power Station to support an increase in around-the-clock renewable supply and cost management.

CleanCo CEO, Tom Metcalfe, said: “At CleanCo we are committed to providing tailored, clean energy solutions to help our customers decarbonise.

“It is our role to develop solutions that meet the unique energy needs of these companies so that they can thrive in a net zero future and I am thrilled BMA has entrusted CleanCo to continue to supply reliable, renewable energy for its operations.”

BHP is on track to achieve its medium-term target to reduce operational greenhouse gas emissions by at least 30% by FY2030 (from FY2020 levels). BHP also has a long-term goal to achieve net zero operational greenhouse gas emissions by 2050.

Ivanhoe Electric planning for all-electric underground fleet and Railveyor tech at Santa Cruz copper project

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Ivanhoe Electric has published the results of an Initial Assessment (IA) carried out on its Santa Cruz copper project, in Arizona, USA, highlighting the potential to build a 5.9 Mt/y underground mining operation that uses an all-electric underground heavy mining fleet, in combination with Railveyor technology for material movement.

The use of an all-electric underground heavy equipment fleet alone represents an estimated 70-80% reduction in Scope 1 emissions when compared to a traditional high-efficiency diesel-powered heavy equipment fleet, Ivanhoe says, adding thatthe use of Railveyor technology would further the efficiencies associated with moving mined mineralisation from underground to surface.

The IA base case assumes 70% of the total electric power requirements for the project will be generated by on-site renewable infrastructure, enabling copper production with very low carbon dioxide equivalent (CO2e) emissions of 0.49 t of CO2e per tonne of copper for Scope 1 and 2 emissions. This compares favourably with a global mining industry average of approximately 3.9 t of CO2e per tonne of copper equivalent, Ivanhoe says. The subsequent prefeasibility study for the project will evaluate the potential use of combined solar power, battery storage and a geothermal-driven microgrid as renewable power sources to provide up to 100% of the electricity requirements for the project.

The Santa Cruz IA outlines a potential 5.9 Mt/y underground mining operation, supported by 105.2 Mt of modelled mill feed with an average grade of 1.58% Cu from the Santa Cruz and East Ridge Deposits, resulting in an estimated 20-year mine life.

The IA focuses exclusively on the high-grade exotic, oxide and enriched domains of the Santa Cruz and East Ridge Deposits, with the oxide and enriched domains of the Texaco deposit not included in the current study (2.7 Mt indicated grading 1.42% total copper and 27.3 Mt inferred grading 1.39% total copper, using a 0.80% cut-off grade).

Future studies could evaluate the potential addition of the large primary sulphide domains at Santa Cruz (76.2 Mt indicated grading 0.88% total copper and 8 Mt inferred grading 0.92% total copper, using a 0.70% cut-off grade) and at the Texaco Deposit (900,000 t indicated grading 1.05% total copper and 35 Mt inferred grading 1.06% total copper, using a 0.80% cut-off grade), subject to market conditions.

Copper recoveries of 95.4% are expected to be achieved through a combination of solvent extraction and electrowinning and conventional froth flotation. The IA includes life of mine production for the project of 1 Mt of copper in the form of 99.99% pure copper cathode and 600,000 t of copper contained in a 48% copper concentrate with very low deleterious elements, such as arsenic or lead.

The IA contemplates initial project capital expenditures of $1.15 billion, and life of mine sustaining capital expenditures totaling $0.98 billion. A three-year construction period is envisioned to develop the underground workings and build the surface processing facilities.

As a result of the small surface footprint required for underground copper mining activities included in the IA, the total land area expected to be required for the mine, plant, tailings storage facilities and potential on-site generation of renewable solar power covers approximately one-third of the total land package.

The IA also contemplates placing 50% of the mine tailings back underground as cemented paste fill. The remaining 50% will be stored on the surface as thickened tailings at 65% solid content. Surface tailings will be contained within a ring dyke dam with a capacity to store 56.7 Mt. Water management associated with tailings storage is minimised as a result of thickened tailings and high evaporation rates in the Sonoran Desert, the company says.

Executive Chairman, Robert Friedland, said: “Completing the Initial Assessment for our Santa Cruz copper project is an important achievement for Ivanhoe Electric as we work to advance a new source of responsibly produced ‘green’ copper in the United States. Our goal is to develop a modern copper mine that produces copper with among the lowest levels of carbon dioxide output in the industry; a product we think has the potential to attract a premium price in the future.

“Using primarily on-site renewable electricity generation, and with the potential to increase that to meet the project’s entire future needs, the IA shows us that we are on the right track to achieving our goal at Santa Cruz and our larger goal of enhancing US supply chain independence for critical metals. We are excited about the future for our Santa Cruz project in Arizona.”

In the IA, twin declines, each measuring 4.3 km, would be developed to access the upper parts of the Santa Cruz and East Ridge deposits. One decline is required for air intake and access, while the other will be required for air exhaust and material movement. To develop the declines, the IA assumes that construction of the portal box cut would begin in 2026, decline development in 2027 and continues through 2028 to access the top portion of the mine. Under these assumptions, stoping activities would begin in 2029 with a one-year ramp up to the full 15,000 t/d capacity.

Mining of the upper portion would proceed for the first eight years before additional capital expenditures are required to extend the declines by 1.9 km. Additional surface infrastructure would be required once mining of the lower portion commences. This would include the second phase construction of a refrigeration plant, ventilation, water handling and material handling.

Mine sequencing would employ typical transverse longhole stopes for the Santa Cruz deposit on a primary-secondary sequence with paste backfill for support. Mining of the Santa Cruz exotic mineralisation has been evaluated using a drift and fill technique with access from the Santa Cruz longhole stoping levels. The East Ridge deposit will apply a drift and fill mining technique with access directly from the twin declines.

Over the total life of mine, 105.2 Mt of mineralised material is expected to be mined. This includes 88.6 Mt from the Santa Cruz deposit, 1.9 Mt from the Santa Cruz exotic mineralisation, 9.8 Mt from the East Ridge deposit and 4.9 Mt of low-grade material required to access the deposits.

Rio Tinto to bolster Diavik renewable power inputs with new solar plant

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Rio Tinto’s Diavik diamond mine in the Northwest Territories of Canada will build the largest solar power plant across Canada’s territories, featuring over 6,600 solar panels that will generate approximately 4,200 MWh/y of carbon-free electricity for the mine.

The solar power plant will provide up to 25% of Diavik’s electricity during closure work that will run until 2029, with commercial production from the operation expected to end in early 2026.

The facility will be equipped with bi-facial panels which will not only generate energy from direct sunlight, but also from the light that reflects off the snow that covers Diavik for most of the year. It will cut diesel consumption at the site by approximately one million liters per year and reduce emissions by 2,900 tonnes of CO2 equivalent, which is comparable to eliminating the emissions of 630 cars.

President and Chief Operating Officer of the Diavik Diamond Mine, Angela Bigg, said: “I am delighted that we will be significantly increasing our renewable power generation with the largest solar power plant in Canada’s northern territories at the Diavik Diamond Mine. Through its wind-diesel hybrid power facility, Diavik is already a leader in cold climate renewable technology and this important project reinforces our dedication to reducing our carbon footprint. I would like to thank both the Government of the Northwest Territories and the Government of Canada for their support to deploy this project.”

The solar power plant will significantly expand Diavik’s renewable energy generation, which already features a wind-diesel hybrid power facility that has a capacity of 55.4 MW and provides the site’s electricity.

The project is supported by C$3.3 million ($2.5 million) in funding from the Government of the Northwest Territories’ Large Emitters GHG Reducing Investment Grant program, and C$600,000 from the Government of Canada’s Clean Electricity Investment Tax Credit.

Government of the Northwest Territories Finance Minister, Caroline Wawzonek, said: “The Diavik solar power plant is a welcome sign of Rio Tinto’s commitment to renewable energy and reducing emissions. The Government of the Northwest Territories is pleased to have provided support through the Large Emitters GHG Reducing Investment Grant program, one of the original pieces of our made-in-the-NWT approach to the federal carbon tax. This collaboration exemplifies our commitment to facilitating sustainable development while reducing greenhouse gas emissions in the Northwest Territories and should be a signal of how our economic development can continue to position us as leaders in these spaces.”

Diavik is working with the Government of the Northwest Territories and community partners to determine how its renewable energy infrastructure can best benefit the region following closure.

Rio Tinto is progressing decarbonisation initiatives across its global operations, with the aim of reducing its Scope 1 and 2 greenhouse gas emissions by 50% by 2030 and to achieve net zero across its operations by 2050.

Construction will start in coming weeks and the solar power plant will be fully operational in the first half of 2024.

The Diavik mine is Canada’s largest diamond producer and produces 3.5-4.5 Mct/y of rough diamonds. Since mining began in 2003, Diavik has produced over 100 Mct of diamonds. Commercial production is expected to end in the March quarter of 2026.

Westgold’s Clean Energy Transition initiative accelerates with start up of first hybrid power station

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The Tuckabianna hybrid power facility – the first of four new hybrid power stations being developed for Westgold Resources – has commenced operations, in Western Australia; a major milestone for the gold miner and its Clean Energy Transition initiative.

The four facilities – at Tuckabianna, Bluebird, Fortnum and Big Bell – are expected to provide substantial reductions in emissions and power costs across Westgold’s operations in the Murchison and Bryah regions of Western Australia, according to Pacific Energy, the provider of these solutions. The system will have a combined installed capacity of 82 MW, providing an expected annual reduction of 38 million litres in diesel fuel usage and approximately 57,000 t/y less CO2-equivalent emissions.

Westgold Chair, Cheryl Edwardes, and Managing Director, Wayne Bramwell, joined business partners, local officials and Traditional Owners on site to open the 17.9 MW facility this week.

The Tuckabianna facility includes a 6 MW solar farm fitted with 11,088 photovoltaic panels, a battery energy storage system with 2.4 MW installed capacity, and a 9.5 MW gas-fuelled power station.

The gas-fired power stations, battery storage and solar farms are owned and operated by Pacific Energy under an Electricity Purchase Agreement, and the LNG is provided by Clean Energy Fuels Australia (CEFA) under an LNG supply agreement. These agreements were signed last year.

These agreements will deliver substantial operating cost savings to Westgold in its 2023-2024 financial years onwards of around A$100/oz ($68/oz) at the then current diesel price and supports its commitment to environmental, social and governance initiatives that will reduce the company’s long term greenhouse gas emissions, it said.

Westgold’s Bramwell said: “Westgold continues to innovate to reduce our greenhouse gas emissions and drive our operating costs down. This new hybrid power facility at Tuckabianna incorporates renewable energy and is a great first step along this journey, with power generated from these facilities energising our mines and processing hubs for decades to come. The successful commissioning of Tuckabianna is a testament to the tireless work of Westgold’s project and operational teams, business partners at Pacific Energy and CEFA and construction crews who have delivered our first power station safely and on schedule.”

Pacific Energy CEO, Jamie Cullen, said: “Congratulations to the Pacific Energy and Westgold project teams for delivering the Tuckabianna hybrid station – on time, and most importantly safely and incident free. Tuckabianna is part of a larger project to consolidate six existing power stations into four high efficiency hybrid power stations that incorporate gas, solar and battery storage systems. Collectively this represents one of the largest fully integrated hybrid power systems in the Australian mining sector.

“As a valued client of Pacific Energy since 2015, we are delighted to join Westgold on its transition to a cleaner energy future.”

Vale hits solar generation capacity at Sol do Cerrado energy complex in Brazil

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Vale says it has reached maximum capacity at the Sol do Cerrado solar energy complex in Brazil, one of the largest solar parks in Latin America.

The project is set to supply 16% of all the energy consumed by Vale in its operations in Brazil, in line with the company’s strategy of achieving zero CO2 emissions by 205o.

Vale reached the full installed capacity of the Sol do Cerrado project, in Jaíba, in the state of Minas Gerais, Brazil, on Tuesday (July 18). On this date, the company received authorisation from the National Electric Energy Agency (ANEEL) for the commercial operation of the last photovoltaic plant of the project, of a total of 17. The project has an installed capacity of 766 MW (peak), equivalent to the consumption of a city of 800,000 inhabitants, Vale says. Operating at full capacity, the solar complex will supply 16% of all the energy consumed by Vale in Brazil.

Sol do Cerrado, whose investments totalled around R$3 billion ($590m), is an important step in helping Vale achieve its climate goals of reducing net carbon emissions (Scope 1 and 2) by 33% by 2030 and zeroing them by 2050. The energy generated by the solar park will reduce Vale’s emissions by 134,000 t/y CO2e, which represents the emission of approximately 100,000 compact cars, according to the company. Vale also expects to reach 100% of renewable energy consumption in Brazil by 2025, and globally by 2030.

Vale began operations at Sol do Cerrado in November last year, with the start-up of four of the 17 photovoltaic plants or sub-parks of the complex, and expanded the operation over the following months, according to authorisations from the regulatory body.

The project has 1.4 million solar panels with an automatic tracking system of the sun’s movement during the day, for greater use of the sun’s rays in energy generation. Some 10.2 million metres of cables are used to conduct the energy.

Currently, Sol do Cerrado has about 100 permanent workers of various qualifications, such as electrotechnicians, electricians and general service assistants. During the implementation of the solar park, between 2021 and 2023, about 3,000 jobs were generated at the peak of activities, with almost 50% deemed to be local labour and 16% of the total jobs taken up by women.

Ludmila Nascimento, Vale’s Energy and Decarbonisation Director, said: “Over the past few months, we have been working hard on the ramp-up of the project, which went exactly as planned. We have successfully connected the 17 plants of the solar park and should already reach peak production next summer. Sol do Cerrado is a complex that brings together local development and renewable energy, contributing to our goal of being leaders in sustainable mining.”

The project also includes a 15-km-long transmission line, with a voltage of 230,000 volts, connecting the Sol do Cerrado and Jaíba collector substations, from where the energy is discharged to the National Interconnected System.

Mineral Resources’ achieves energy strategy milestone with Wonmunna solar installation

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Mineral Resources (MinRes) says it has marked an important milestone in its energy strategy with the successful installation of a 2.1 MW solar-battery system at its Wonmunna iron ore project in the Pilbara region of Western Australia.

Located 80 km northwest of Newman, the Wonmunna mine was purchased as an undeveloped project in the 2021 financial year. First ore was achieved just five months after construction began at the site and during the 2022 financial year, production from Wonmunna ramped up to 5 Mt/y.

Installation of the 5B Maverick solar technology at the Wonmunna site – complete with more than 4,000 solar panels – was completed during the 2023 financial year. Following successful testing and optimisation works, the technology is now providing significant benefits for site operations and reducing dependency on diesel fuel, MinRes says.

The combined solar-battery system will produce more that 30% of the mine’s power requirements and ultimately cut diesel consumption by approximately 760,000 litres each year, while reducing the site’s carbon emissions by around 2,000 t/y of carbon dioxide equivalent.

In addition, the crusher at the site is powered 100% by the system during the middle of the day when renewable output meets peak plant load.

During the warmer summer months, the system can achieve more than 40% displacement on any given day – and, with a 20-year life span, it can be redeployed to other operations once Wonmunna reaches its end-of-life, MinRes says.

Chief Executive Energy, Darren Hardy, said the Wonmunna solar and battery array at Wonmunna was a positive step forward in the company’s renewable energy strategy.

“MinRes is committed to pursuing renewable energy opportunities where we can and our team has been working hard to deliver a solar array and battery solution that delivers optimum output at Wonmunna,” Hardy said. “Together with natural gas, renewables will play an important role in our energy future, and MinRes continues to pursue off-grid solar power and energy storage solutions to support our remote locations.”

Gas and LNG power stations currently supporting MinRes’ lithium operations at Mt Marion in the Goldfields and Wodgina in the Pilbara are delivering significant emissions savings, according to the company. This includes a 64 MW capable power station at Wodgina, which is the largest of its kind on a mine site in the southern hemisphere, the company says.

At the upcoming Onslow Iron project, also in the Pilbara, MinRes will install a range of energy solutions designed to offset diesel with alternative fuels and renewable energy options, energy storage, and electrification of mobile equipment and transport.

MinRes says it recognises the need for meaningful action to address climate change and is committed to investing in activities that reduce the carbon intensity of its operations and maintaining best-practice environmental, social and governance performance.

The company’s Roadmap to Net Zero Emissions outlines MinRes’ pathway towards a transition to gas, renewable energy and other emerging technologies to support its operations and reduce its carbon intensity – including the company’s goal to achieve of net-zero emissions by 2050.

Zenith Energy and Northern Star seal renewable energy-focused PPA at Jundee

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Zenith Energy has converted the preliminary works agreement and term sheet it had in place with Northern Star Resources related to bolstering the power supply to the Jundee gold mine in Western Australia with a renewable energy Power Purchase Agreement.

Jundee is an existing mining operation that will have wind, solar and battery retrofitted into the mix and integrated into the existing gas power station. The renewable generation being added includes 24 MW of wind, 16.9 MWp of solar, and 12 MW/13.4 MWh of battery energy storage.

Zenith says this new energy mix will result in 56% of the mine site’s power coming from renewable sources, contributing towards the aim of cutting Jundee’s Scope 1 and 2 carbon emissions by 35-50% by 2030.

Currently all ore is sourced from Jundee underground operations which yield circa-1.8 Mt/y of ore. There are three underground portals which provide access to the various underground lode structures – Barton, Gateway and Invicta portals. Underground mining is being carried out by an up-hole long-hole open stoping sequence as its primary method. No backfill or paste is used.

The Jundee processing circuit is a conventional carbon-in-leach plant with a hard-rock processing capacity of approximately 3 Mt/y. The process consists of a single toggle overhead eccentric swing jaw crusher followed by a SAG and ball milling circuit incorporating gravity recovery and carbon-in-pulp process achieving 92% recoveries, according to Northern Star.

Zenith Energy gears up to supply 95 MW of hybrid power to Liontown’s Kathleen Valley project

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Zenith Energy has converted the Letter of Award it signed with Liontown Resources to supply electricity to the Kathleen Valley lithium project in Western Australia into a Power Purchase Agreement.

The PPA will see Zenith supply the project with electricity for a period of 15 years as part of a 95 MW hybrid power station setup at the mine.

Zenith has, since the signing of the Letter of Award, announced in September, progressed the planning, engineering and design works for the hybrid power station, including the order of long-lead items such as the wind turbines.

With 46 MW of emission-free power generation capacity, the 95 MW hybrid power station is currently expected to be one of the largest off-grid wind-solar-battery storage renewable energy facilities in the mining industry in Australia.

The thermal components are designed to operate in “engine off” mode at various times, enabling Liontown to operate from 100% renewable energy during periods of high wind and solar resource, the companies say.

The hybrid power station is expected to start up around the same time as the Kathleen Valley process plant is commissioned, currently slated for the first half of 2024.

The plant will include wind generation from five wind turbines each capable of generating 6 MW. A 16 MWp fixed axis solar photovoltaic array coupled to a 17 MW/19 MWh battery energy storage system will provide additional clean energy, supported by synchronous condensers that provide critical system stability and resilience, Zenith said. The thermal power component will comprise 27 MW of gas generation and 5 MW of diesel standby generation.

Kathleen Valley is one of the world’s largest and highest-grade hard-rock lithium deposits and, with an initial 2.5 Mt/y production capacity, is expected to supply circa-500,000 t/y of 6% lithium oxide concentrate, according to the company. With first production expected in June quarter of 2024, the deposit will also produce tantalum pentoxide.

Nevada Gold Mines kicks off construction of 200 MWAC TS Solar Facility

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Nevada Gold Mines (NGM) says it is building a 200 MWAC (Megawatt, alternating current) photovoltaic solar facility to accelerate its decarbonisation program in line with Barrick’s Greenhouse Gas Reduction Roadmap.

NGM, majority owned and operated by Barrick Gold Corporation, hosted a celebratory groundbreaking ceremony this week, marking the commencement of construction of its TS Solar Facility. The facility is adjacent to NGM’s TS Power Plant near Dunphy, Nevada.

The solar array will be constructed in a single phase with commercial production expected in the June quarter of 2024.

NGM is partnering with three Nevada-based contractors to complete the civil, solar substation and mechanical construction. Domestically-sourced steel piles are arriving on site in preparation for module foundation construction and tracker installation. At peak, the project is expected to employ approximately 250 people.

NGM Executive Managing Director, Peter Richardson, said: “At NGM, we embed the principles of partnership and sustainability into every decision we make. We continually seek opportunities to source materials and labour as close to our projects as possible. The TS Solar Facility is a great example of how we can partner with local resources on a project that not only benefits the environment, but also provides sustainable long-term social and economic benefits.”

Upon completion, the project will supply renewable energy to NGM’s operations and realise 254,000 t of CO2-equivalent emissions reduction per year, according to NGM. This will result in an 8% emission reduction from the company’s 2018 baseline.

NGM has committed to a 20% carbon reduction by 2025, which will be achieved through the TS Solar facility and the modification of NGM’s TS Power Plant, providing the ability to use cleaner burning natural gas as a fuel source.

Barrick is targeting an overall 30% reduction in emissions by 2030 with the goal of achieving net-zero by 2050.

Taseko Mines using innovation to increase production and efficiencies

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The Taseko Mines story is indicative of the current environment miners find themselves in – maximise productivity to grow margins at existing operations or invest in innovative new methods of extracting critical metals that come with a reduced footprint.

The Vancouver-based company is pursuing both options at the two main assets on its books – the Gibraltar copper mine in British Columbia, Canada, and its Florence Copper project in Arizona, USA.

Gibraltar, owned 75% by Taseko, initially started up in 1972 as a 36,000 t/d operation. It was shut down in 1998 due to low copper prices before Taseko restarted it in 2004. In the years since, the company has invested over $800 million in the mine, increasing the throughput rate to 85,000 tons per day (77,111 t/d), where it’s been operating at since 2014.

The asset now sits as the second largest open-pit copper mine in Canada – with life of mine average annual production of 130 MIb (59,000 t) of copper and 2.5 MIb of molybdenum.

Stuart McDonald, President and CEO of the company, says the company continues to work on the trade-off of upping throughput – potentially past the nameplate capacity – and improving metallurgical recoveries at the operation.

This became apparent in the latest quarterly results, when Taseko reported an average daily throughput of 89,400 tons/d over the three-month period alongside “higher than normal” mining dilution.

The company believes Gibraltar can improve on both counts – mill throughput and mining dilution.

“We were optimistic coming into the new pit (Gibraltar Pit) that, based on the historical data, we could go above 85,000 tons/d as we got settled in and mined the softer ore,” McDonald told IM. “We still believe there are opportunities to go beyond that level, but, at some point, it becomes an optimisation and trade-off between throughput and recoveries.

“In our business, we’re not interested in maximising mill throughput; we’re interested in maximising copper production.”

On the dilution front, McDonald believes the problem will lessen as the mining moves to deeper benches in the Gibraltar Pit.

“As we go deeper, the ore continuity improves, so we hope the dilution effect will continue to improve too,” he said.

“The dilution rate is still not quite where we want it to be, so it’s a matter of looking at our operating practices carefully and following through a grade reconciliation process from our geological model through to assays from our blast holes, assays into the shovel bucket and all the way through to the mill.”

‘Assays into the shovel bucket’?

McDonald explained: “We do use ShovelSense® technology on two of our shovels, so that helps us assess the grade of the material in the shovel bucket.”

To this point, the company has leveraged most value from this XRF-based technology, developed by MineSense, when deployed on shovels situated in the boundaries between ore and waste. This offers the potential to reclassify material deemed to be ‘waste’ in the block model as ‘ore’ and vice versa, improving the grade of the material going to the mill and reducing processing of waste.

ShovelSense has been successful in carrying out this process with accuracy at other copper mines in British Columbia, including Teck Resources’ Highland Valley Copper operations and Copper Mountain Mining’s namesake operation.

McDonald concluded on this grade reconciliation process: “We just have to make sure we are tracing the material through all of those steps and not losing anything along the way. Gibraltar is a big earthmoving operation, so we must continue to keep the material flowing as well as look at the head grade.”

A different type of recovery

In Arizona at Florence Copper, Taseko has a different proposition on its hands.

Florence is a project that, when fully ramped up, could produce 40,000 t of high-quality copper cathode annually for the US domestic market.

It will do this by using a metal extraction and recovery method rarely seen in the copper space – in-situ recovery (ISR).

The planned ISR facility consists of an array of injection and recovery wells that will be used to inject a weak acid solution (raffinate – 99.5% water, 0.5% acid) into copper oxide ore and recover the copper-laden solution (pregnant leach solution) for processing into pure copper cathode sheets. The mine design is based on the use of five spot well patterns, with each pattern consisting of four extraction wells in a 100 ft (30.5 m) grid plus a central injection well. This mine outline and associated infrastructure comes with a modest capital expenditure figure of $230 million.

The company has been testing the ISR technology at Florence to ensure the recovery process works and the integrity of the wells remains intact.

Since acquiring Florence Copper in November 2014, Taseko has advanced the project through the permitting, construction and operating phase of the Phase 1 Production Test Facility (PTF). The PTF, a $25 million test facility, consists of 24 wells and the SX/EW plant. It commenced operations in December 2018.

Over the course of 18 months, Taseko evaluated the operational data, confirmed project economics and demonstrated the ability to produce high-quality copper cathode with stringent environmental guidelines at the PTF, the company says.

McDonald reflected: “We produced over 1 MIb [of copper] over this timeframe and then switched over from a copper production cycle into testing our ability to rinse the orebody and restore the mining area back to the permitted conditions.

“We’re proving our ability to do the mining and the reclamation, which we think is a critical de-risking step for the project.”

Over an 18-month period, Taseko produced 1 MIb from the ISR test facility at Florence

Taseko says Florence Copper is expected to have the lowest energy and greenhouse gas-intensity (GHG) of any copper producer in North America, with McDonald saying the operation’s carbon footprint will mostly be tied to the electricity consumption required.

“Our base case is to use electricity from the Arizona grid, which has a combination of renewables, nuclear and gas-fired power plants,” he said. “In the longer-term, there are opportunities at Florence to switch to completely 100% renewable sources, with the most likely candidate being solar power.

“At that point, with renewable energy powering our plant, we could be producing a copper product with close to zero carbon associated with it.”

Gibraltar has also been labelled as a “low carbon intensity operation” by Skarn Associates who, in a 2020 report, said the operation ranked in the lowest quartile compared with other copper mines throughout the world when it comes to Scope 1 and 2 emissions.

When it comes to the question of when Florence could start producing, Taseko is able to reflect on recent successful permitting activities.

In December 2020, the company received the Aquifer Protection Permit from the Arizona Department of Environmental Quality, with the only other permit required prior to construction being the Underground Injection Control (UIC) permit from the US Environmental Protection Agency (EPA).

On September 29, the EPA concluded its public comment period on the draft UIC it issued following a virtual public hearing that, according to Taseko, demonstrated strong support for the Florence Copper project among local residents, business organisations, community leaders and state-wide organisations. Taseko says it has reviewed all the submitted comments and is confident they will be fully addressed by the EPA during its review, prior to issuing the final UIC permit.

Future improvements

In tandem with its focus on permitting and construction at Florence, and upping performance at Gibraltar, the company has longer-term aims for its operations.

For instance, the inclusion of more renewables to get Florence’s copper production to carbon-neutral status could allow the company to benefit from an expected uptick in demand for a product with such credentials. If the demand side requirements for copper continue to evolve in the expected manner, it is easy to see Taseko receiving a premium for its low- or no-carbon product over the 20-year mine life.

At Gibraltar, it is also pursuing a copper cathode strategy that could lead to the re-start of its SX-EW plant. In the past, this facility processed leachate from oxide waste dumps at the operation.

“As we get into 2024, we see some additional oxide ore coming out of the Connector Pit, which gives us the opportunity to restart that leach operation and have some additional pounds coming out of the mine,” McDonald said.

Alongside this, the company is thinking about leaching other ore types at Gibraltar.

“There are new technologies coming to the market in terms of providing mines with the opportunity to leach sulphides as well as oxides,” McDonald said. “We’re in the early stages of that work, but we have lots of waste rock at the property and, if there is a potential revenue stream for it, we will look at leveraging that.”