COMMINUTION & CRUSHING
Carbon-constrained comminution
The entire industry is aware of the statistics about the comminution sector ’ s water and energy use . The question now is : how do we rationalise the use of these resources while boosting output to meet growing industry demand ? Dan Gleeson looks for answers from the processing community
The mining sector ’ s drive for energy and water efficiency is relentless , with companies reporting on their Scope 1 , 2 and 3 emission status and operational water draw on an annual basis in sustainability reports .
The pressure to continuously bring down these metrics is stirring the technology community into action , knowing that the low-hanging operational fruit can only be picked for so long and more transformational moves are needed to reach the sector ’ s ultimate net zero destination .
Weir out to transform flowsheets
Having proven out its own Enduron ® high pressure grinding roll ( HPGR ) product and assembled complementary downstream equipment , Weir is now ready to show the mining sector how it can transform the wider minerals processing flowsheet .
This message came through loud and clear at the recent SAG 2023 conference in Vancouver , Canada , and has been getting louder in the months since .
For instance , in December , the company released the results of a study that highlighted an opportunity to reduce energy use and emissions in comminution by leveraging three alternative technology combinations .
The study , presented by Paula Cousins , Chief Strategy and Sustainability Officer , during a COP28 panel discussion , showed that replacing conventional technology with innovative new solutions can cut energy use by 40 % while also avoiding 50 % of CO 2e emissions . It was the first study of this kind to use the World Business Council for Sustainable Development ’ s Avoided Emissions Guidance to evaluate mining processes , with the results independently assured by SLR Consulting Limited .
Three of Weir ’ s technology combinations were evaluated against a Semi-Autogenous Grinding ( SAG ) mill and ball mill ( SABC circuit ) design for an archetypal mine processing 15 Mt / y of copper ore in Chile . Each circuit was based on a ‘ rock to recovery ’ system boundary – reducing rock direct from the mine to a size that enables the mineral to be recovered .
The combinations under the spotlight were the Enduron HPGR to replace the SAG mill at the initial grinding stage , the Enduron HPGR plus
A recent study showcased that the use of an Enduron HPGR ( pictured ), an STM Minerals ’ vertical stirred mill and Eriez ’ s HydroFloat coarse particle flotation solution in place of a traditional SABC circuit design for an archetypal mine processing 15 Mt / y of copper ore in Chile could cut energy use by 40 % while also avoiding 50 % of CO 2e emissions
STM Minerals ’ vertical stirred mill ( VSM ) to replace SAG and ball mills , and the addition of Eriez ’ s HydroFloat coarse particle flotation ( CPF ) solution to the HPGR and VSM equipment . All this collectively comes under the “ Transformational Flowsheets ” Weir has been promoting .
It was the combination of all three that provided the biggest impact – around 40 % less energy and the ability to avoid up to 50 % of CO 2e emissions – with the trio also consuming less water than the SABC circuit it was compared against .
For Tim Lundquist , General Manager – Mining Sales ( Comminution ), North America , it is studies like this that should be leading more mining companies to re-evaluate flowsheet thinking of the past .
“ I find it very interesting that , even with this massive industry push for carbon neutrality and greenhouse gas emission reductions , SAG mills continue to find their way into mill circuits ,” he told IM at the recent SME MineXchange Conference and Expo , in Phoenix , Arizona . “ Replacing tumbling mills with HPGRs and complementary equipment like VSMs is not just a
38 International Mining | APRIL 2024