Researchers have found that a step-change in mineral processing may drastically reduce mineral waste, while creating a source of sustainable sand
The extraction of sand from seas, rivers, beaches and quarry’s has an impact on the environment and its surrounding communities. Therefore, finding ways to create sustainable sand could be huge.
Sand is the second-most exploited resource, used to create windowpanes, sunglasses, concrete, asphalt and so much more – these uses are seemingly endless. However, we are running out of it.
‘Ore-Sand’ presents steps towards global sustainability
Researchers from the University of Geneva (UNIGE) and the University of Queensland’s Sustainable Minerals Institute (SMI) have found that a step-change in mineral processing could drastically reduce mineral waste – the world’s largest waste stream – while creating a sustainable source of sand.
According to research ‘ore-sand’ has the potential to address two global sustainability challenges simultaneously: ‘Ore-sand: A potential new solution to the mine tailings and global sand sustainability crises.’
It is estimated that 50 billion tons of sand are used each year, concrete, glass, electronic chips: sand has many applications as previously mentioned. Composed of small mineral particles, this granular material comes from sensitive dynamic environments such as seas, beaches, lakes and rivers or, from static land-based environments such as ancient river deposits and rock quarries.
Over the past two decades demand has tripled primarily due to urbanisation and population growth, a trend which is expected to continue.
Sand mining is leading to erosion in riverbanks and is vital for the protection of coastal regions – therefore increasing risk of flooding and in some countries has caused loss of communities and livelihoods. Creating sustainable sand would lessen the need for sand extraction and therefore reduce environmental and societal consequences.
Two sustainability challenges with one solution – sustainable sand
UNIGE’s Adjunct Professor at Department F.-A. Forel for environmental and aquatic sciences of the Faculty of Science, Pascal Peduzzi said: “Ore-sand has the largest potential in volume for reducing the amount of sand taken in the natural environment.
“By using what has been so far considered as ”left over” material, the project gives an important impetus towards a more circular economy.”
The production of ore-sand can help reduce the production of mineral mining waste and thus the further build-up of mine tailings. Mineral wastes from the mining of ores currently represents the largest waste stream on the planet, estimated between 30-60 billion tonnes per year.
These residues come from crushing operations to extract certain metals from the rock.
Mineral wastes from the mining of ores currently represents the largest waste stream on the planet
SMI’s Development Minerals Program Leader Professor Daniel Franks said ore-sand has the potential to address two global sustainability challenges simultaneously.
Franks said: “Separating and repurposing these sand-like materials before they are added to the waste stream would not only significantly reduce the volume of waste being generated but could also create a responsible source of sand.”
Major reductions in global mine tailings and carbon emissions
In a 12-month study, the team independently sampled and investigated sand produced from iron ore mining, pioneered by Vale S.A in Brazil, which has previously experienced tailings dam failures.
After an analysis of the chemical properties and some refining operations, the team were able to demonstrate that part of the material stream which would otherwise end up as mining residues could be used as a substitute for construction and industrial sand.
“If these results can be replicated with other types of mineral ores there is potential for major reductions in global mine tailings” – Professor Daniel Franks
Daniel Franks said: “By mapping mining locations worldwide and modelling global sand consumption, we discovered that almost a third of mine sites can find at least some demand for ore-sand within a 50 km range. This could contribute to at least 10% reduction in the volume of tailings generation at each site. Simultaneously, almost half of the global sand market (by volume) could find a local source of ore-sand.
“For example, ore-sand could potentially substitute 1 billion metric tons of sand demand in China” explains Franks.
In addition, the life cycle assessment of ore-sand, based on the Vale case, shows that substituting naturally sourced sand with ore-sand has the potential to lead to net reductions in carbon emissions during sand production. While this sounds promising, the resultant carbon emissions by transport remains a key consideration.
