Rio looks to use old mines for solar power

Australia’s largest iron ore exporter is considering using former mines in the Pilbara to host the solar power farms it needs to displace the 3 million tonnes of carbon emissions generated each year by its network of 17 mines.

Rio Tinto has forecast it will produce between 323 and 338 million tonnes of the key steelmaking ingredient iron ore in 2024. The company is scouting for sites to locate the 700 megawatts of renewable generation needed to replace four gas-fired generators that power its Pilbara operations, and generate about a third of its annual carbon output in Australia.

Rio Tinto will start decarbonising its Pilbara trains by combining diesel and battery-powered locomotives.Credit: Krystle Wright

The global mining giant is considering disused mines for possible solar farms, and is also negotiating with traditional landowners over other suitable locations.

“We are looking at a couple of our sites and our pits where we have closed,” Rio’s port and rail operations managing director Richard Cohen said. The company is also eying wind power and actively monitoring conditions at key locations.

The remaining two thirds of Rio’s annual carbon footprint comes from the diesel consumed by huge trucks that haul the iron ore out of mine pits and rail locomotives that pull two kilometre-long carriages weighing 28,000 tonnes, along with other sources, he said.

Rio estimates it will need to ramp up its renewable generation to one gigawatt to reduce its emissions by 50 per cent.

‘We see iron ore remaining a large and very attractive market as we go forward and that’s why we’re continuing to invest in it.’

Simon Trott, Rio Tinto’s head of iron ore

“We’re really focusing now on what are the sites that we need to progress,” Simon Trott, Rio’s chief executive of iron ore, said.

The company installed a 34 megawatt plant with 81,000 solar panels covering 106 hectares at its newest Pilbara mine, Gudai-Darri, where it has been producing ore for less than a year and already reached annual capacity of 43 million tonnes. Rio said it will boost Gudai-Darri’s production to 50 million tonnes, adding haul drugs and diggers at a cost of around $70 million.

Rio is banking on two undeveloped, high-grade ore deposits to help its decarbonisation journey and buttress future green steelmaking capacity, Rhodes Ridge in the Pilbara and Simandou in Guinea.

“As the steel industry decarbonises, these deposits are set to provide us with the resource options that we need to respond to whatever direction the steel industry takes in the future,” Trott said.

Rhodes Ridge will underpin Rio’s Pilbara production for decades, with an estimated 6.7 billion tonnes of mineral resource at an average grade of 61.6 per cent.

Pilbara iron ore is typically of a lower grade suitable for the carbon-emitting traditional blast furnaces that use metallurgical coal in the steelmaking process. The company is confident it can develop alternative low carbon steelmaking processes that will maintain the viability of Pilbara’s output, including a pilot project for its trademark BioIron that uses raw biomass and microwave energy instead of metallurgical coal to convert ore to metallic iron.

Rio estimates that over the next 20 years worldwide demand for iron ore will exceed the amount consumed during the last 50 years. Current global annual consumption is around 2 billion tonnes. “We see iron ore remaining a large and very attractive market as we go forward and that’s why we’re continuing to invest in it,” Trott said.

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