Influence of Environmental Conditions on the Behaviour of Tailings from Tungsten Mining for Sustainable Geotechnical Applications and Storage

Modern societies require increasingly large amounts of minerals and metals for their development. Therefore, huge amounts of waste must be stored in safe and cost-effective massive tailing storage facilities that would benefit from using tailings in sustainable geotechnical applications within the context of the circular economy. However, to consider tailings as assets, the long-term behaviour of these unconventional geomaterials under realistic environmental conditions must be assessed. This paper focuses on the effects of the environmental conditions on the behaviour of tailings from tungsten mining by experimentally determining their major physical and mechanical properties for three different conditions: twenty-months-aged undisturbed samples and reconstituted samples, with the latter being fresh and three months. The results confirm that twenty-months-aged undisturbed and fresh reconstituted tailings have significantly different mechanical behaviour, while three-months-aged reconstituted samples show an in-between behaviour as if the material regenerates and improved its behaviour with time due to physical and chemical processes. These ageing processes are experimentally confirmed by measuring the electrical conductivity in the samples. The results confirm that optimising the design of tailing storage facilities and using these geomaterials in sustainable geotechnical applications must consider the existing environmental conditions and the potential tailings’ mechanical changes due to ageing.