Tag Archives: LOESCHE

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.

OZ Minerals, Loesche team up following West Musgrave vertical roller mill test work

OZ Minerals, following a successful prefeasibility study of vertical roller mills (VRM) at the West Musgrave project in Western Australia, has signed a “Partnering Agreement” with Loesche.

The agreement with the leading original equipment manufacturer (OEM) of VRMs will help the company as it moves to the next phase of the project, OZ Minerals said.

“By working in a collaborative, innovative and transparent way, we believe we will deliver superior outcomes for the project when compared to more traditional ways of engaging with suppliers,” OZ Minerals said.

In November 2017, OZ Minerals and Cassini, which owns 30% of West Musgrave, announced that the West Musgrave project would progress to a prefeasibility study. This prefeasibility study timeline was extended in 2019 to complete a detailed evaluation of additional value-add opportunities, the most significant of which was the use of a dry VRM to reduce power consumption.

The study, released earlier this year, showed off plans for a 26-year open-pit mine with “bottom quartile cash costs” and average production of circa-28,000 t/y of copper and circa-22,000 t/y of nickel in concentrates, OZ Minerals said.

It also included details of an “innovative mineral processing plant” that would be built on site.

The grinding circuit for West Musgrave was expected to consist of two stages of crushing followed by two parallel VRMs treating nominally 5 Mt/y each. The second stage of crushing and VRMs replaced a traditional SAG mill, ball mill and pebble crushing circuit.

OZ Minerals explained in the study: “Vertical roller mills are widely used in the grinding of cement plant feeds and products, slag, coal and other industrial minerals, with thousands currently in operation worldwide. The mill has benefits in reducing power consumption by circa-15%, no ball charge grinding media, higher flotation recovery and can be ramped up and down in response to the availability of low-cost renewable energy.”

The VRM uses compression-style comminution principles taking 75 mm rock to flotation feed size in the one machine, according to OZ, adding that the application of the VRM had reduced processing costs and provided a circa-2% improvement in nickel recovery compared with a previous scoping study.

“The technology has been peer reviewed for West Musgrave by an independent expert and has been substantially de-risked through a series of pilot tests whereby 5 t of West Musgrave ore has been tested,” the company said.

Reviewing the prefeasibility study, OZ Minerals Chief Executive Officer, Andrew Cole, said: “We have been able to achieve a further significant reduction in carbon emissions and power demand through the adoption of vertical roller mills as the grinding mill solution and a flotation flowsheet which achieves metal recovery at a much coarser grind size than was previously considered in the design.

“This lower power usage has resulted in a reduction in operating costs, while the use of dry grinding from the vertical roller mills has also resulted in an improvement in nickel recovery.”

Another innovation the company plan to use at West Musgrave include the use of hybrid renewables that could include a combination of wind and solar energy, battery back-up, and diesel or gas.

Mining at West Musgrave is modelled to be conventional drill, blast, load and haul and is assumed to be contractor operated during the first five years of operation, transitioning to owner operate in year six.

The haulage fleet will comprise up to 25 220 t haul trucks and optionality is being maintained to allow for these trucks to be fully autonomous in the future, OZ Minerals said.

LOESCHE vertical roller mill to soon start up at Chinalco JV copper plant

A new LOESCHE vertical roller mill is in the process of being assembled at Aluminium Corp of China’s (Chinalco) copper smelting plant in the southern Chinese province of Fujian.

The three-roller mill will be operated by Chinalco’s Southeast Copper Ltd subsidiary and is able to grind 100 t/h of copper matte to a fineness of 20% with a sieving residue of 0.074 mm, according to LOESCHE.

Chinalco is managing the project as a joint venture with the provincial government of Fujian. The plant, in Ningde Zhangwan Industrial Zone, will be completed in the second half of 2018 and is due to produce 400,000 t/y of copper.

The LOESCHE mill has already been delivered and is now in the process of being assembled, the company noted.

The contract partner of LOESCHE and the planner of this plant is Changsha Nonferrous Metallurgy Design Institute Co Ltd from Changsha, China.