Geopolymers from mining tailings for more sustainable raw material supply

For ecologic and economic reasons tailings, waste rock and water management become progressively important factors in the mining industry. The European Union funded project ‘Integrated mineral technologies for more sustainable raw material supply’ (ITERAMS) aims to (1) close the water cycle of the mineral processing plant (i.e. minimizing the release of wastewater to the adjacent environment), and (2) to use tailings (and waste rock) as raw materials for geopolymers. This will (1) enable significantly more efficient water recycling at the mining sites, (2) deliver cost savings and added income due to the valorisation of solid waste residues, and (3) minimize the overall environmental footprint of the mining industry and will therefore help improving its performance and as a consequence its social position. The developed solutions influence the total lifecycle of the mining operation, as they provide input to project planning and operational phases as well as to the closure and recultivation. In this paper, the valorisation of the tailings and the waste rock is discussed. The main applications of the geopolymer products are (1) backfill material to fill open cavities from the mining operation and (2) a cover for surface deposits of tailings to store them environmentally safe – i.e. seal them off from surface water streams and oxidising conditions.