A team of scientists and engineers from the University of Sheffield has developed a new technology that opens the door to the stabilisation of huge earthwork structures such as tailing dams, using sustainable, naturally sourced materials to replace cement.
Tailing dams are vast embankments used to store mining byproducts, of which over 350 billion tonnes a year are produced globally. When these dams fail it has a catastrophic impact on the environment, causing landslides and loss of life.
Currently the earthwork dams are stabilised using cement, which is harmful for the environment, contributing heavily to the world’s CO2 emissions; or not stabilised at all which can lead to their failure.
The team at Sheffield has found that by using naturally sourced alternatives to cement, such as locust bean gum which is a vegetable gum extracted from the seeds of the carob tree, these structures can be better stabilised in a more sustainable way.
They used samples of the earth from tailing dams to understand the composition and work out which additives, in the right combination, would be the best to replace cement in binding and stabilising the soil. The newly developed technology then allowed the team to rapidly screen and develop bespoke biopolymer/soil mixes up to 50 times faster than using current methods.
Dr Sarah Staniland, from the University of Sheffield’s Department of Chemistry, said: “Last year the collapse of a tailing dam in Brazil led to hundreds of deaths and released 12 million cubic meters of mining waste over the Paraopeba region. Our research enables us to develop sustainable solutions to prevent devastating disasters like this in the future.
“Using naturally sourced materials not only stabilises the dams far more effectively than cement, but is far more sustainable. One tonne of cement produces around the same amount of CO2, and these huge structures are currently about 10 per cent cement, by using naturally sourced materials the dams would be three times stronger with only one per cent additive.”
Samuel Armistead, project researcher from the University of Sheffield, said: “Our work will revolutionise how we tackle stabilising these dams throughout the world in a sustainable way. We hope to translate this new environmentally friendly technology to produce the next generation of sustainable geotechnical solutions, curtailing our global reliance on cement.”
“By understanding the best binding materials they were able to directly translate this to large-scale structures such as the dams, and hope to translate this research in the future to a wide range of earthworks such as railway embankments and flood defences.”