Modern designs for TSFs Discussing the move to more modern TSF designs, Liefferink explains that prevailing global design trends for TSFs is a shift away from high-volume, water-intensive slurry deposition towards lower-water, more controlled, and more actively monitored tailings management systems. Several key developments underpin this transition. Filtered tailings (dry stacking): Water is mechanically removed prior to deposition, significantly reducing free water content and, in turn, lowering the risks of liquefaction and seepage. Thickened or paste tailings: These technologies reduce water content relative to conventional slurry systems, resulting in improved beach slopes and smaller supernatant ponds. Backfill: A portion of tailings is returned underground rather than deposited in surface TSFs. In the Witwatersrand context, this approach is particularly relevant. South Deep mine reports that part of its tailings stream is used as backfill, reducing surface storage requirements while enhancing underground ground support. Its Doornpoort TSF further incorporates advanced controls, including underdrainage systems, scavenger boreholes, seepage collection systems, lined return-water dams, and a centralised control room that monitors flow rates, temperatures, process inputs and outputs, alarms, events, and water balances. “For new or expanded facilities, regulatory
occurred, including the collapse of side slopes at two TSFs following the liquidation of Mintails, where deficiencies in slope stability management and stormwater control were identified as contributing factors. Industry response and initiatives related to TSF At a global level, the primary industry response has been the Global Industry Standard on Tailings Management, developed through the Global Tailings Review with the involvement of International Council on Mining and Metals (ICMM), United Nations Environment Programme, and Principles for Responsible Investment. The standard establishes a significantly more rigorous framework across governance, alternatives analysis, design criteria, monitoring, emergency preparedness, community engagement, closure planning, and public disclosure. “ICMM members committed to meeting conformance deadlines of 5 August 2023 for facilities classified as extreme or very high consequence, and by 5 August 2025 for all other applicable facilities, supported by public progress disclosures. By late 2025, the ICMM reported substantial progress, particularly for higher-consequence facilities, with more than 80% of members achieving full conformance in this category.” According to Liefferink, in South Africa, although implementation has been active, it has been uneven. “Literature from the Southern
requirements increasingly mandate engineered containment measures, including compacted low-permeability layers, geomembranes or composite liners (where appropriate), underdrains, seepage collection systems, toe drains, and monitoring boreholes.” A case in point is DRDGOLD, which is installing a high-density
African Institute of Mining and Metallurgy highlights challenges faced by operators in aligning
The prevailing global design trends for TSFs is a shift away from high-volume, water-intensive slurry deposition towards lower- water, more controlled, and more actively monitored tailings management systems.
existing practices and regulatory frameworks with the standard’s 77
polyethylene (HDPE) geomembrane liner at its Far West Gold Retreatment (FWGR) regional TSF. Similarly, Harmony Gold has lined its expanded Kareerand TSF, while Pan African
requirements. Company- level disclosures from Gold Fields and Sibanye-Stillwater indicate conformance with the Global Industry Standard on Tailings Management (GISTM),
Resources plans to deposit residue from its Mogale Tailings Retreatment operations on a lined facility. Importantly, modern TSFs are increasingly incorporating advanced monitoring and governance systems, including piezometers, survey instrumentation, satellite-based monitoring (such as InSAR), and formal independent tailings review boards. For new Witwatersrand TSFs, the likely aim should be: • stronger seepage interception and liner philosophy, • tighter dirty/clean water separation, • higher monitoring density, • lower-water deposition where feasible, • more backfill and retreatment to reduce surface inventory. “Mining houses are taking positive steps towards addressing TSF, albeit selectively. Backfill is clearly implemented at South Deep. GISTM-aligned governance, independent review and monitoring systems are being implemented across major miners’ TSFs. Large-scale global adoption of fully filtered/dry- stack tailings is growing, but for ultra-large gold operations conventional or thickened systems remain common because of throughput and cost constraints,” concludes Liefferink. n
supported by independent review, consequence classification and enhanced disclosure. Both companies continue to strengthen systems and technical practices in line with evolving best practice.
Although larger, listed mining companies have generally adopted a more proactive approach—particularly in relation to governance, disclosure, and emergency planning—this progress is, however, not uniform across the sector. Performance remains markedly stronger among well- capitalised companies than among smaller operators, legacy asset holders, or marginal retreatment businesses. This disparity is reflected in the gap between the adoption of global standards by ICMM members and the broader mining industry. Within the Witwatersrand, one of the most significant and proactive trends is the retreatment and rehabilitation of surface tailings. Companies such as Harmony Gold, Pan African Resources, DRDGOLD, and Sibanye-Stillwater are advancing large-scale retreatment of legacy gold tailings. This approach is framed both as a commercial opportunity and a bid to reduce historical environmental liabilities, reprocess problematic materials, and progressively rehabilitate legacy deposits.
JULY 2026 | www.modernminingmagazine.co.za MODERN MINING 23
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