The most effective water management strategies in mining are those embedded at the design stage rather than retrofitted once problems emerge. This is according to Marnus Koorts, Director of Capital and Process at Weir, who says mines must treat water as a core design variable from the earliest phases of a project, rather than as an issue to be addressed later at the tailings facility.

According to Koorts, water management can no longer be viewed as a box to tick during the tailings design phase. Instead, it must be integrated into project planning alongside geology, metallurgy and financial considerations. “This shift is essential if mines are to manage risk, cost and ESG obligations over the life of mine,” he says.

In practical terms, this means feasibility teams should begin with the end state in mind by defining what a safe and stable tailings product should look like and then designing backwards from that point. “You need to start at the end and then design holistically,” Koorts explains. “This includes asking what the ideal tailings solution looks like and what material is going to be fed into that solution.”

One of the most important design principles, he notes, is recognising that every cubic metre of water added at the front end of the process will ultimately need to be pumped, treated and stored. “If you design a system that runs on less water and reduces your water input into the system, you have automatically got less water to remove on the downside.”

When this reality is not addressed during the feasibility stage, mines often end up with flowsheets that are overly diluted, energy-intensive to pump and difficult to dewater before deposition. Retrofitting additional thickeners or filters at a later stage is significantly more expensive than designing water-lean circuits from the outset.

In many African mining jurisdictions, the assumptions underpinning older tailings facilities are already being challenged by increasingly extreme rainfall events. This makes early and integrated water management thinking even more critical.

“If a mine designs tailings facilities to handle a certain amount of water, it could run into problems as a result of unprecedented rainfall,” Koorts points out. “This is directly linked to safety, production continuity and reputation.”

For Weir, embedding water and tailings considerations into the original flowsheet is not merely an environmental exercise, but a core life-of-mine risk management strategy.

“The conclusion is clear: water and tailings management must be built into the flowsheet from the very first scoping study, otherwise operations risk locking in higher capital costs, increased operating expenditure and long-term liabilities that will be far more difficult - and costly - to address later,” he says.

“In a world where water risk is rapidly becoming capital risk, projects that treat water management as a front-end design discipline rather than a back-end compliance exercise are the ones most likely to secure funding, operate reliably and retain their social licence over the long term,” Koorts concludes.