The mining
business environment is constantly changing; it would not be an overstatement
to say that the paradigm is shifting, as mines face new challenges. The
pressing issues are not only about low-grade ore bodies and mines going deeper,
but also about long-term environmental impacts.
Mining involves the processing of mined ore to separate valuable minerals, leaving behind huge volumes of waste tailings. Driven by mining volumes, globally generated tailings are estimated to total up to 3.2 billion tons for copper and up to 1.8 billion tons for iron per year. Water conservation and the cost of tailings and reclamation are also becoming increasingly significant factors for sustainable and economically viable mining and long-term survival.
The practice
of dewatering tailings, however, is still limited to few areas globally. According
to Metso’s analysis, only ~5% of tailings generated in 2018 were dewatered into
thickened, paste, or dry tailing. We estimate that by 2025 the share of
generated tailings that are dewatered will increase to ~13%.
Challenging the conventional
The way
tailings are handled can have a long-term impact on economic efficiency as well
as on community well-being and ecosystem sustainability. The recent tailings
dam failures have brought safety and environmental concerns to the forefront;
there have also been stronger regulatory compliances affecting the social
license to operate in many regions.
Metso views
dry filtered tailings as the most viable and long-term solution for tailings handling, as it not only helps in recycling
significantly more water to the concentrator, but also allows for a smaller
freshwater footprint compared to traditional tailings impoundments. Contrary to
the conventional belief, dry tailings are much more CAPEX and OPEX efficient
compared to wet or paste/thickened tailings. Technology is evolving and
shifting the gears towards the adoption of smart and hybrid solutions that
maximize ore and water recovery while optimizing operational costs.
Enabling a water-positive world
Today, about 70% of the mines operated by the major mining companies are in countries where water scarcity is considered as the major risk. Therefore, responsible water use is the primary driver of the growing interest in tailings dewatering – especially in countries like Peru, Chile, the US and South Africa, where the significant mines are in dry areas.
The
industry needs future-ready and smart filtration solutions to solve complex
tailings handling challenges. Backed by proven technology and industrial
knowledge, Metso is ahead of the curve in developing the most efficient
dewatering solutions with an intense commitment to maximize water recovery and
reuse.
Getting future ready
A lot of
old tailings facilities have residual mineral values, or secondary metals that
were not of interest at the time. With the advent of novel technologies, mining
companies are now figuring out ways to extract valuable metals from tailings.
There are ongoing feasibility studies and capabilities to look into legacy dams
enabling customers to plan an “end of the mine” strategy.
Reprocessing
could provide opportunities to help in environmental reclamation, while at the
same time offering an attractive investment opportunity. Treating tailings
ponds as a potential source for converting “waste to value” would surely help
in changing the way the mining industry has been perceived all these years.
(By Niclas Hällevall, VP, Beneficiation Solutions)