Civil Engineering June 2022 | Vol 30 No 5

22 June 2022 Civil Engineering T hese GISTM requirements include aspects such as diver- sion of clean water away from the tailings complex, capturing and containing water that falls within the TSF, measuring and recording of flow data and simulating the likely effects of climate change. Being a key element in the transpor- tation of tailings, water has in recent years received more attention as mines work to reduce the water volumes reporting to tailings facilities while in- creasing the volumes that can be re-used in the processing plant. The rainfall that falls directly onto the TSF needs to be managed and stored in a safe manner. The water should be drained through the penstocks safely and quickly to reduce the risk of overtopping the TSF basin walls. The GISTM also highlights that the water balance model and the associated water management plans must be applied throughout the structure’s lifecycle, even in perpetuity, to protect against unintentional releases, and this requires stochastic as well as historical water bal- ance modelling. As mines look to become more resilient to climate change, they will need to carefully balance the likely risks against rising infrastructure costs. PRACTICAL CONSIDERATIONS Monitoring and controlling water-re- lated variables on TSFs means applying appropriate instrumentation for water level sensors – in dam levels as well as Global standard prioritises better measuring, managing of TSF water Peter Shepherd Partner and Principal Hydrologist – Lead SRK Consulting Dr Simon Lorentz Corporate Consultant and Principal Hydrologist – Lead SRK Consulting Lindsay Shand Associate Partner and Principal Environmental Geologist – Lead SRK Consulting Simon Bruton Senior Hydrologist SRK Consulting With water posing a significant risk to the stability of a tailings storage facility (TSF), the Global Industry Standard on Tailings Management (GISTM) places significant focus on water management as part of its sweeping realignment of what global stakeholders now expect of mines. Construction of a large lysimeter for measuring infiltration and evaporation from covers on a waste rock impoundment Measuring surface runoff from vegetative covers on a tailings dam side slope