MINE POWER
Powering a new dynamic
Miners have some difficult power choices to make to hit their net zero goals in the next few decades . Dan Gleeson explores some of their options
Decarbonising the fixed plant side of the mine site has been viewed by many as comparatively easy when compared with
‘ greening ’ mobile equipment fleets .
Thermal liquid fuel-powered generation alternatives have been in place for off-grid mines for several decades now , while some on-grid operations have been able to scale up their renewable inputs as power producers have made long-term investments to tap ‘ green energy ’ sources .
Yet , there is still some debate over how remote mine sites make the next leap and achieve higher levels of renewable penetration without making drastic changes to the way they operate or their site footprint .
Take OZ Minerals ’ West Musgrave coppernickel project in Western Australia , situated 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 , as an example .
In the 2020 West Musgrave prefeasibility study , OZ Minerals said it planned to achieve 70- 80 % renewable penetration at the site based on the use of solar and wind power , supplemented by battery storage and diesel or trucked gas-fired generation .
For OZ Minerals to achieve such high penetration , it had to devise a flowsheet including energy efficient dry grinding , flotation technology able to achieve metal recovery at a much coarser grind size than previously considered and evaluate “ load scheduling ” to match plant power demand with the availability of renewable energy supply .
This ‘ load scheduling ’ concept could see the 12 Mt / y plant operate at full capacity when solar and wind power are in plentiful supply , before scaling it back and operating off battery storage during the night or when wind speeds are reduced .
The idea of running a plant below capacity at any time of the year – aside from during maintenance stoppages – is a novel concept in mining , but one that , as OZ Minerals is showing , may be the route to take to achieve the truly high levels of penetration that the sector requires to hit its ‘ net zero ’ goals to 2030 , 2040 and 2050 .
An open door for renewables
Aggreko has its own net zero goals out to 2050 that have a bearing on the solutions it is providing the mining sector , demonstrated with a target to reduce diesel fuel used in customer solutions by at least 50 % by 2030 .
A leading provider of mobile and modular power solutions , the company has been introducing increasing amounts of solar and wind energy to off-grid mines , often integrating these with battery storage solutions and microgrid networks .
Aggreko ’ s Global Head of Mining , Rod Saffy , said most of the projects the company is working on have an element of renewable expectation , with the flexibility in technology and commercial models Aggreko offers having great appeal with customers .
“ Not only do they have the benefit of our experience with a variety of technologies , but we continue to trial the latest in thermal and renewable products to bring the best solutions to our customers ,” he told IM .
To introduce these solutions at mine sites , the company has increasingly been taking a partnership approach that sees it shoulder some of the technology risk associated with implementing
One of the world ’ s largest renewable energy microgrids was installed by Aggreko at Gold Fields ’ Granny Smith gold mine in Western Australia , which is fully integrated with Aggreko ’ s existing 27 MW natural gas generation at the site
these new power solutions by providing flexible solutions that can scale up and down .
“ Currently , the Aggreko control platform has the ability to handle a variety of step loads and transient loads that mine sites are experiencing ,” Saffy said , referencing the installation of one of the world ’ s largest renewable energy microgrids for Gold Fields ’ Granny Smith gold mine in Western Australia .
“ At Granny Smith , as operational power loads change as a result of capacity growth and introduction of new technology , the Aggreko power station remains ready for these demandside changes ,” he said . “ The thermal and solar generation design , which is supported by energy storage , ensures that these transient loads are dealt with seamlessly .”
Saffy said this project , in addition to the 25.9 MW hybrid solar and thermal power solution Aggreko will use to power operations at Gold Fields ’ Salares Norte high altitude mine in Chile , represent examples of where careful investment and a long-term partnership can help accommodate higher levels of renewable energy at mine sites .
Just one of the investments in technology Aggreko is making is in the form of mobile and containerised photovoltaic solar solutions that , according to Nicolas Boruchowicz , Head of Renewables and Energy Storage solutions , bring the benefits of solar integration with the flexibility required to employ them at mines and
46 International Mining | JANUARY 2022