Tailings management

Tailings facilities, if not managed correctly, could pose significant risks to our employees, host communities and the environment. We manage these facilities as aligned with guidance from locally and globally recognised standards and best practice frameworks that support safe dam design, effective operations and environmental accountability. Our tailings facilities also present a substantial opportunity to advance circular economy outcomes through recovery of valuable materials and reuse of waste streams.

Implementing robust engineering, dam design and operational management

We manage TSFs following high engineering standard and applying strict water management. Our approach for new and proposed TSFs begins with the comprehensive design phase to deliver safe and stable facilities with structural integrity. We incorporate drainage systems and prevent run-off or seepage into surrounding ecosystems. At Hidden Valley in Papua New Guinea, TSF 1 is designed to seep, with seepage monitored through regular sampling and testing. These measures provide long-term structural and environmental stability and consider factors like rainfall patterns, soil erosion and groundwater interactions. We also implement dust control measures such as dust netting and vegetation planting to reduce airborne particles.

We aim to increase our TSF capacity at Hidden Valley to support the feasibility of extended life-of-mine. The mine’s TSF capacity is constrained, and opportunities to extend the life-of-mine require secure and compliant TSF expansion. We have received regulatory approval for the mining tenement extension and are awaiting a decision on our revised environmental permit. Once necessary approvals are in place, the board will consider the feasibility of extending the life-of-mine.

Conducting risk management, layered assurance, oversight and compliance

We embed risk management in the lifecycle of TSFs, from the design and construction of new TSFs, the operating phases and in our final closure designs, including:

• Freeboard legal compliance to maintain safe capacity for excessive rain and operational water levels management with monthly surveys (drone and instrumented)
• Instrumentation, seepage monitoring and erosion control
• Site-level emergency response plans and regular drills; four-siren early-warning system downstream of Hidden Valley

To monitor our performance and compliance with regulations, we conduct independent audits and regular inspections, with management, the deposition contractors and specialist consulting engineers and specialist who assist with the construction of facilities. Additionally, our teams are trained in emergency response.

Our level of alignment with GISTM, or selected elements of the GISTM, is a matter we are continuing to assess noting the practicality and economic feasibility of retrofitting historical TSFs to achieve full alignment with the standard. Read more about the GISTM.

Reducing dust emissions

Harmony Gold implements a variety of measures to control dust from TSFs key measures include: 

• Revegetation and phytoremediation involves planting indigenous trees, grass and other vegetation on exposed TSF surfaces to create a sustainable basal cover and prevent wind erosion. Certain plants or trees species can absorb, degrade or immobilise environmental pollutants or contaminants. This approach enhances ecological restoration of affected areas, stabilises soil and reduces erosion while providing long-term solutions to TSF pollution management.
• Dust netting barriers to reduce wind speed and subsequent dust fallout in surrounding areas.
• Water and chemical dust suppressants on TSF surfaces and roads bind fine particles and prevent them from becoming airborne.

Read more about these measures in Air quality

Retreating and reclaiming South African TSFs

Tailings retreatment offers substantial competitive advantages and environmental benefits (on completion of reclamation). It tends to be a lower-risk, non-labour intensive, low-energy usage, safer and lower-cost option to conventional mining. Tailings retreatment plays a critical role in supporting a circular economy by recovering valuable minerals from previously discarded waste, reducing the need for new extraction and minimising environmental impacts.

We are exploring the feasibility for reprocessing several inactive TSFs in the Free State, Gauteng and North West. This will also enable the rehabilitation of reclaimed TSF footprints. All reclaimed material will be deposited on existing, recommissioned or where required, new TSFs.

All new and proposed facilities are designed to prevent seepage and reduce the risk of contamination to surrounding land and groundwater. The re-engineered geomembrane liner, as used in the construction of the Kareerand TSF extension for example, is more advanced than the current required class C barrier and offers enhanced performance by significantly reducing groundwater impact risks. The innovative design maximises water recovery, supporting a higher return of water for reuse.

Collaboration and partnerships

In South Africa, we are collaborating with a local supplier to transfer mine rehabilitation skills to local communities while completing the Doornkop TSF dust mitigation project. At Hidden Valley, we collaborate with the MRA regularly to provide dam performance and address any safety risks and operational issues. We also engage with third-party auditors and the ITRB.