MINE POWER
Trade-off time
Assessing the stationary power needs of current and future mines requires integrated thinking and expert opinions , Dan Gleeson reports
The mining sector is in the process of asking some very hard questions of itself , but so is every other industry around the world .
The overriding question for all companies with industrial operations is : ‘ Can we continue to electrify to achieve net-zero status on renewable energy alone ?’
The answer to this question , for many sectors , is inextricably tied to politics and public and private funding of networks and grids , as Andrew Sullivan , Project Manager at Stantec , implies .
“ If we ignore mining for just a second and look at the North American and European grids , there are big questions there ,” he told IM . “ Can those grids even handle electrification of industry ? That goes from charging up electric cars , to energising all industries on the grid .
“ Politicians are largely ignoring these bigger questions given the terms they are working on , so it is hardly surprising that we , in the mining sector , are still in the process of ironing out the finer details .”
A significant percentage of that mining sector is operating off-grid , meaning they may not benefit from renewable energy injection into grids .
It is unquestionable that the mining sector has embraced renewable energy over the last decade , with remote mines all over the globe powering entire process plants off ‘ zero carbon ’ sources . As impressive as those feats are , they do not – in most cases – account for mobile equipment fleets , meaning the job is only partly complete .
Reducing the peak
At a basic level , off-grid mine developments looking to start-up in the next decade need to , first , assess both their base and peak energy loads , according to Sullivan . These numbers are incredibly important considerations as more processes are electrified .
“ The other part to that is looking at where the mine is located and assessing if there is enough renewable energy to create that base load and service that peak load ,” he said .
Depending on the location , there may be a ‘ bridge ’ option that leverages power infrastructure that starts with ‘ low carbon ’ energy before transitioning to ‘ no carbon ’ power – similar to the haulage dynamic where companies are investing in trolley assist infrastructure that can help diesel-powered trucks become more effective and efficient ahead of a switch to those vehicles powered off batteries . There may also be options to build connections to grids increasingly backed by renewables – think of hydro power in Quebec , Canada .
Sullivan sees some ‘ stranded ’ mine development projects that do not have the best wind or solar generation prospects considering small modular reactors ( SMRs ). Yet he admits that , from a regulatory perspective , there is currently no differentiation between permitting one of these to power a mine site and permitting a full-scale nuclear reactor for grid-based generation .
Any on-site renewable energy input that is generated by variable means – wind and solar , for instance – will require a storage component to reinforce this supply . This could be a battery energy storage solution , a gravitational method with a captive reservoir , or a compressed gas through a turbine .
Stantec carried out the EPCM contract for Alinta Energy ’ s gas-fired and solar-generated hybrid power solution for two iron ore mines in the Pilbara of Western Australia
These high-level assessments also need to be complemented with an investigation into optimising the whole site plan to rationalise energy use – an area Sullivan believes will be enhanced with the adoption of new technology .
The use of autonomous haulage could make mine sites more efficient , he says ; it could also reduce the size of the required mine camp , which also impacts overall site energy requirements .
“ You could also use machine learning and artificial intelligence to help optimise the charging cycles on these electric , autonomous trucks in the future ,” Sullivan added . “ This could end up reducing your overall peak power needs , with truck charging being staged based on grid requirements , battery status and truck location on the haulage route .”
Similar AI tools could be used alongside powerful computation and mine design in the exploration stage to create mines with the lowest possible footprint , which has a knock-on effect on site power requirements .
“ You could end up using machine-learning models to develop a narrow-vein mining plan to make mining more accurate , which may lead to a smaller tailings pond and reduced backfill generation ,” Sullivan said . “ Do all these things getting smaller reduce the envelope for your power too ? It ’ s a question worth considering against several other factors .”
It is this type of exercise that really points to the need to take a whole lifecycle view into account before agreeing on any mine power plan .
JANUARY 2025 | International Mining 39