The water recycling performance of gold miner Gold Fields’ South Deep mine, in Gauteng, has improved from 78% in 2024 to 84% by the end of 2025 as part of efforts to reduce freshwater abstraction and increase water recycling and reuse, says environmental advocacy organisation Federation for a Sustainable Environment (FSE) CEO Mariette Liefferink.

Gold Fields informed the FSE of the developments as part of the organisation’s engagement with mining operations on environmental and water-related issues.

The South Deep mine has implemented an integrated water stewardship strategy aligned with Gold Fields’ sustainability commitments.

“The strategy focuses on reducing pressure on shared water resources, supporting long-term water security and catchment resilience, and improving local water access. The mine is also targeting further reductions in freshwater withdrawals over time.”

The strategy is structured around four pillars: water efficiency, water quality protection, catchment management and climate adaptation, adds Liefferink, who notes that Gold Fields’ capital investment in the strategy totals about R253-million.

As for waste management, she notes that a R75-million thickened tailings project – initiated in 2024 and being implemented over three years – is intended to increase water recovery through the production of higher-density tailings while reducing evaporation and seepage losses.

“South Deep advised that the project also improves tailings stability, safety and environmental performance.”

Liefferink adds that South Deep’s tailings storage facilities were also installed with plume interception boreholes to intercept and prevent plume migration while supplementing supply to reverse osmosis plants, consequently allowing for the production of potable water for operational use.

Regarding process water handling, South Deep completed a R178-million upgrade of its South Shaft return water dam in 2025, increasing process water storage capacity and reducing environmental risk through the installation of a high-density polyethylene liner and concrete ballast.

On water quality protection, she highlights that South Deep is a non-acid-generating operation, owing to the relatively low sulphide content of its ore and the controlled management of any subtailings plume within its operational boundary.

Water quality of the operation is monitored through upstream and downstream surface water sampling and groundwater monitoring to allow for the early detection and mitigation of potential impacts.

Mine and process water are treated through reverse osmosis plants with a combined capacity of about 5-million ℓ a day, producing water that meets operational and potable standards. A third reverse osmosis plant, planned for 2027 at an estimated cost of R44-million, is expected to further reduce freshwater intake requirements and strengthen water security, she adds.

Further, South Deep is also working with host communities, regulators and other stakeholders to support the responsible management of shared water resources and contribute to long-term catchment resilience.

It also conducts ongoing climate risk assessments, including a current flood study, to guide adaptive water management measures, she adds.

“These actions are intended to safeguard water security over South Deep’s life-of-mine, estimated at more than 80 years, while supporting operational continuity and community resilience in the face of climate variability,” concludes Liefferink.