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OZ Minerals wades into uncharted renewables territory at West Musgrave

You do not get much more remote than OZ Minerals’ West Musgrave copper-nickel project. Located in the Ngaanyatjarra Aboriginal Lands of central Western Australia, it is some 1,300 km northeast of Perth and 1,400 km northwest of Adelaide; near the intersection of the borders between Western Australia, South Australia and the Northern Territory. The nearest towns include the Indigenous Communities of Jameson (Mantamaru), 26 km north; Blackstone (Papulankutja), 50 km east; and Warburton (Milyirrtjarra), 110 km west.

This makes the company’s ambition of developing a mine able to produce circa-32,000 t/y of copper and around 26,000 t/y of nickel in concentrates that leverages 100% renewable generation and can conduct ‘zero carbon mining’ even bolder.

OZ Minerals is not taking this challenge on by itself. In addition to multiple consultants and engineering companies engaged in a feasibility study, the company has enlisted the help of ENGIE Impact, the consulting arm of multinational electric utility company ENGIE, to come up with a roadmap that could see it employ renewable technologies to reach its zero ambitions.

“We’re providing an understanding of how they could decarbonise the mine to achieve a net zero end game,” Joshua Martin, Senior Director, Sustainability Solutions APAC, told IM.

While ENGIE Impact is focused solely on the energy requirements side of the equation at West Musgrave, its input will prove crucial to the ultimate sustainability success at West Musgrave.

Having worked with others in the mining space such as Vale’s New Caledonia operations (recently sold to the Prony Resources New Caledonia consortium), Martin says OZ Minerals is being “pretty ambitious” when it comes to decarbonisation.

“Our job is to assess if the renewable base case stacks up for West Musgrave, create multiple decarbonisation pathways for their consideration and look at what technology should be adopted to achieve their overall aims,” he said.

This latter element is particularly important for an off-grid project like West Musgrave, which is unlikely to start producing until around mid-2025 should a positive investment decision follow the upcoming feasibility study.

While solar, wind and battery back-up are all likely to play a role in the power plans at West Musgrave – technologies that are frequently factored into hybrid projects looking to wean themselves off diesel or heavy fuel oil use – more emerging technologies are likely to be factored into a roadmap towards 100% renewable adoption.

“We are developing a series of roadmaps that factor in where we think technologies will be in the future,” Martin said. “These roadmaps come with a series of decision gates where the company will need to take one option at that point in time if they are to pursue that particular decarbonisation pathway.”

These roadmaps utilise ENGIE Impact’s consulting and engineering nous, as well as the consultancy’s PROSUMER software (screenshot below) that is used on any asset-level decarbonisation project roadmap, according to Martin.

“This software was specifically built for that purpose,” Martin said. “There is nothing on the market like this.”

Progress at PFS level

OZ Minerals’ December 2020 prefeasibility study update went some way to mapping out its decarbonisation ambition for West Musgrave, with a 50 MW Power Purchase Agreement that involved hybrid renewables (wind, solar, battery, plus diesel or gas).

The company said in this study: “Modelling has demonstrated that circa 70-80% renewables penetration can be achieved for the site, with the current modelled to be an optimised mix of wind, solar and diesel supported by a battery installation.”

OZ Minerals said there was considerable upside in power cost through matching plant power demand with the availability of renewable supply (load scheduling), haulage electrification to maximise the proportion of renewable energy used, and the continued improvement in the efficiency of renewable energy solutions.

ENGIE Impact’s view on hydrogen and electric haulage in the pit may be considered here, complemented by the preliminary results coming out of the Electric Mine Consortium, a collaborative mine electrification project OZ Minerals is taking part in with other miners such as Evolution Mining, South32, Gold Fields and IGO. And, on the non-electric pathway, ENGIE Impact’s opinion is being informed by a study it is undertaking in collaboration with Anglo American on developing a “hydrogen valley” in South Africa.

If OZ Minerals’ early technology views are anything to go by, it is willing to take some risk when it comes to adopting new technology.

The preliminary flowsheet in the prefeasibility study factored in a significant reduction in carbon emissions and power demand through the adoption of vertical roller mills (VRMs) as the grinding mill solution, and a flotation component that achieves metal recovery at a much coarser grind size than was previously considered in the design.

Loesche is working with OZ Minerals on the VRM side, and Woodgrove’s Direct Flotation Reactors got a shout out in the process flowsheet.

While mining at West Musgrave is modelled to be conventional drill, blast, load and haul, the haulage fleet will comprise up to 25, 220 t haul trucks, with optionality being maintained to allow for these trucks to be fully autonomous in the future, OZ Minerals said.

‘True’ zero miners

OZ Minerals is aware of the statement it would make to industry if it were to power all this technology from renewable sources.

“With a future focus on developing a roadmap to 100% renewable generation, and reducing dependency upon fossil fuels over time, West Musgrave will become one of the largest fully off-grid, renewable powered mines in the world,” it said in the updated PFS. “The solution would result in the avoidance of in excess of 220,000 tonnes per annum of carbon dioxide emissions compared to a fully diesel-powered operation.”

The company’s Hybrid Energy Plant at Carrapateena in South Australia, whose initial setup includes solar PV, battery storage, diesel generation and a micro-grid controller, will provide a test case for this. This is a “unique facility designed to host experiments on how various equipment and energy technologies interact on an operating mine site”, the company says.

Martin and ENGIE Impact agree OZ Minerals is one of many forward-thinking mining companies striving for zero operations with a serious decarbonisation plan.

“The mining projects we are working on are all looking to achieve ‘true’ net zero operations, factoring in no offsets,” he said. “Having said that, I wouldn’t say the use of offsets is an ‘easy out’ for these companies. They can form part of the decarbonisation equation when they have a specific purpose, for instance, in trying to support indigenous communities.”

These industry leaders would do well to communicate with each other on their renewable ambitions, according to Martin. Such collaboration can help them all achieve their goals collectively, as opposed to individually. The coming together of BHP, Rio Tinto, Vale, Roy Hill, Teck, Boliden and Thiess for the ‘Charge on Innovation Challenge’ is a good example of this, where the patrons are pooling resources to come up with workable solutions for faster charging of large surface electric mining trucks.

“In the Pilbara, for example, there is a real opportunity to create a decarbonisation masterplan that seeks to capitalise on economies of scale,” he said. “If all the companies work towards that end goal collaboratively, they could achieve it much faster and at a much lower cost than if they go it alone.”

When it comes to OZ Minerals, the miner is clearly open to collaboration, whether it be with ENGIE Impact on decarbonisation, The Electric Mine Consortium with its fellow miners, the recently opened Hybrid Energy Plant at Carrapateena, the EU-funded NEXGEN SIMS project to develop autonomous, carbon-neutral mining processes, or through its various crowd sourcing challenges.

Wiluna Mining lays renewable energy groundwork with Contract Power extension

Wiluna Mining Corp has signed a 10-year contract extension with Contract Power Group that will see the power provider charge up the Wiluna Mining Operation in Western Australia until at least 2031.

The contract is geared towards meeting the forward needs of the Stage 1 development project at Wiluna, to provide a total rated power output of the power station of 14.1 MW. It will also re-configure the power station to increase gas generation and add a 2 MW battery energy storage unit to significantly reduce the need for back-up diesel generation, with four diesel generators being removed.

The new pact will also allow amortisation of costs over a longer period, therefore reducing Wiluna’s overall operating power charges; the company said.

And, when it comes to the Stage 2 development expansion project in 2023 at Wiluna, the contract will provide a solid base for a future mixed renewables power station, the company said.

Back in October, Wiluna Mining’s board gave the thumbs up to the Stage 1 development, which will see the company transition from its current production profile of producing 62,000 oz/y from mining free milling ore through the current 2.1 Mt/y carbon-in-leach processing facility, to initially producing 100,000-120,000 oz/y of gold and gold in concentrate. This will be implemented using the current, recently refurbished crushing circuit, the previously expanded mill circuit and a new 750,000 t/y concentrator by October 2021, the company said.

Wiluna then intends to increase production of gold and gold in concentrate by, at a minimum, doubling the mining rate and the concentrator to produce circa-250,000 oz/y by the end of 2023/early 2024 as part of Stage 2.

Contract Power, a subsidiary of Pacific Energy, has provided Wiluna’s power – a mix of natural gas and diesel power backup – since June 2016.

“Contract Power Group are experts in efficient generation of electrical power and in decarbonisation by harnessing off-grid wind or solar power,” Wiluna said. “Wiluna are refining its plans with Contract Power Group to include decarbonisation within our methods of power generation at site. This may also moderate our exposure to future volatility in the cost of hydrocarbon fuels.”

Wiluna will now focus on renewable power studies and options during 2021 and 2022 to:

  • Assess the right mix of renewables including solar, wind or pumped storage options;
  • Determine how best to integrate renewables into the total power delivery for an expanded operation; and
  • Optimise the decarbonisation of power generation with reliability and cost effectiveness.

Milan Jerkovic, Wiluna Mining’s Executive Chair, said: “We look forward to working with Contract Power to not only transitioning the Wiluna Mine once again into one of Australia’s biggest and most profitable gold mines, but to helping it become one of Australia’s cleanest mines.”

Anglo American and ENGIE agree on ‘green’ electricity supply for Quellaveco

Anglo American and ENGIE’s Peru-based subsidiary have signed an agreement to convert the current contracted energy supply for the Quellaveco copper project to 100% renewable sources, in addition to agreeing on another eight years of energy supply for the mine, starting in 2029, from “green energy” inputs.

The agreement will see Quellaveco, a copper project being developed by Anglo and Mitsubishi Corp, become the first mining operation to promote the construction of a non-conventional renewable energy plant, according to ENGIE.

As part of the pact, ENGIE Energía Perú has agreed to convert the total electricity supply for Quellaveco (187 MW) to 100% green energy, with 150 MW of supply over eight years from 2029 also coming from green energy sources.

ENGIE Energía Perú will source the renewable energy from its Punta Lomitas wind power plant, an in-development wind farm with a joint nominal capacity of 260 MW located in Ocucaje-Ica and a 60 km transmission line connecting the plant with the National Interconnected Electric System. The project has been granted a generation and transmission concession by the Ministry of Energy and Mines, and construction is expected to start in the second half of 2021, the company says.

Tom McCulley, CEO of Anglo American in Peru, said: “We are working from different areas to contribute to a healthy environment. Our goal is to transform the very nature of the industry to ensure a safer, cleaner and more sustainable future.

“By resorting to the use of higher precision technologies, such as those that Quellaveco will have, as well as by focusing on consuming less energy and less water, we will reduce our environmental footprint for every kilogram of copper that we produce, starting in 2022.”

Rik De Buyserie, CEO of ENGIE Energía Peru, added: “Thanks to the renewable energy certificates delivered by the Punta Lomitas Power Plant to supply the demand for the Quellaveco project, we are proud and committed to accompany our client Anglo American and mining in Peru, on their path to carbon neutrality.”

Quellaveco, owned 60% by Anglo and 40% by Mitsubishi Corp, comes with a production blueprint of 300,000 t/y of copper over the first 10 years of the mine, with first production expected in 2022.

Renewable energy use can bring savings to Africa mining sector, report claims

THEnergy and Voltalia’s latest report on the use of renewable energy in the Africa mining sector says the industry can realise significant cost savings when employing these power solutions.

The authors said the mining sector has shifted from phase one – where the focus of renewable power adoption was on integrating and testing out the reliability of these solutions – to phase two – where potential cost savings are being considered.

“In the last few years, more and more mining companies have adopted wind and solar systems to reduce their energy costs at remote off-grid mines,” THEnergy and Voltalia said. “In this first phase, the initial focus was on the integration capabilities as miners were afraid that adding intermittent renewables such as solar and wind could affect the reliability of power supply and even lead to production losses.”

In various microgrid applications, renewables combined with diesel, heavy fuel oil (HFO), or gas have proven to provide reliable power supply to remote mines, according to the two firms.

“For almost all mines, the integration of renewables will have a positive impact on their energy cost position. Mining companies do not have to invest their own money; independent power providers (IPPs) invest in the renewable energy infrastructure and sell electricity to mines through power purchase agreements (PPAs),” THEnergy and Voltalia explained.

Thomas Hillig, Managing Director of THEnergy, a consultancy focused on microgrids/mini-grids and off-grid renewable energy, said this second market phase is characterised by price competition.

“With the support of a leading renewable energy player, the new report analyses how IPPs can offer extremely competitive PPAs to remote miners,” he said.

Large IPPs take advantage of economies of scale on components for solar and wind power plants not only for remote mining projects but also for much bigger grid-connected plants, the two firms said.

“Market leaders have managed to optimise the planning and construction processes substantially. However, conducting projects in remote locations, especially in Africa, requires an extended experience,” they added. Among the challenges of undertaking projects in Africa is financing, which requires relationships with local and international banks, according to THEnergy and Voltalia.

“Cost optimisation does not necessarily mean minimising capital expenditure but rather focusing on the total lifetime of the project and including operation and maintenance. It is also important to take the interplay of the different energy sources into consideration. Not every kWh of solar and wind energy generated means equivalent fossil fuel savings. When gensets run at suboptimal loads, they lose efficiency and require additional maintenance,” the two firms said.

Alexis Goybet, Head of Hybrid Solutions at Voltalia, a player in the renewable energy sector, said his company has much experience in renewable energy projects, including solar-diesel hybrid microgrids, projects in remote locations and in developing countries.

“Our experience adds up to our economies of scale in procurement and translates into significant overall cost-reductions in the range of 20-30% in comparison to new market entrants,” he said.

These overall cost reductions will make solar and wind energy extremely attractive for many mines, according to the two firms, with the number of remote mines adding renewables to diesel, HFO or gas expected to grow quickly all over Africa.

There are already several mining companies that have made – or are planning to make – this transition in Africa, as can be seen by the map above (credit: THEnergy, Voltalia). This includes Resolute Mining and its Syama underground gold mine in Mali, Newmont Mining and its Akyem gold mine in Ghana and B2Gold and its Otjikoto operation in Namibia.

In the past month alone, Barrick Gold and GoviEx Uranium have also stated plans to use hybrid solutions at their Loulo and Madaouela assets, respectively.