Closing the gap: Integrating tailings storage facility closure into mine lifecycle planning

Mining, like any other industry, is fundamentally driven by profit. But unlike many other sectors, the profit-generating phase of a mining operation usually accounts for only a small portion of its lifecycle. Historically, mining companies have disproportionately concentrated innovation, resources, and investment on active extraction phases, compared to rehabilitation and closure.

When closure isn’t done properly, there can be lasting negative consequences on the environment – such as degraded water quality – and the surrounding communities who rely on natural resources.

Given the comparatively short nature of the extraction phase, this presents both a risk – given the challenges and costs associated with rehabilitation and closure, such as the need for perpetual water treatment – and an opportunity to create lasting social, economic, and environmental benefits beyond production. These benefits can include delivering restored ecosystems and repurposed lands capable of supporting local development, renewable energy projects, or sustainable livelihoods.

As mining is a temporary land use, communities and governments increasingly expect a positive post-mining legacy in return for access to mineral resources. Delivering this requires integrating closure-related activities into mine planning and operations from day zero – a challenging task. Among all aspects of integrated mine closure good practice, few are as complex as managing a tailings storage facility (TSF) through to post-closure.

Why are TSFs such a complex aspect of mine closure?

TSFs are intricate and vast structures, often spanning several kilometers. They are not only among the most visible and enduring symbols of a mine’s environmental footprint, but also present challenges in closure that mirror their immense scale.

For example, during the operational phase of a TSF, the high moisture content of tailings keeps them geochemically quite inert, as water acts as a barrier that limits exposure to oxygen and slows chemical reactions such as acid rock drainage and metal leaching. During closure, a TSF is usually de-watered to support long-term geotechnical stability, but this process can expose tailings to air, which increases the risk of oxidation and the release of contaminants. As a result, de-watering requires alternative geochemical risk management strategies, such as dry covers or chemical treatments.

Similarly, TSFs may initially be constructed to withstand weather extremes likely to be encountered during their operational life. Closure, however, requires long-term structural stability that extends far beyond this period. When closure considerations and changing climate conditions are not factored into the original TSF design, significant engineering works can be required, resulting in prolonged closure timelines and higher costs.

Cross disciplinary collaboration needed to optimise closure outcomes from TSFs

A fundamental step in addressing the challenges associated with TSF closure is ensuring that tailings management decisions are seamlessly integrated into closure planning, and vice versa. Mine closure and tailings management are often treated as separate disciplines. Yet, the success of both hinges on their effective integration.

Recognising this need and opportunity, ICMM undertook the task of updating both the Integrated Mine Closure Good Practice Guide (v3) and the Tailings Management Good Practice Guide (v2). These updated resources now emphasise early-stage processes that embed mine closure considerations into tailings management – and tailings management into closure planning – equipping operators with the tools to align these disciplines for more responsible and successful outcomes.

Three core concepts underpinning good closure outcomes from TSFs

For a variety of technical, social and environmental reasons, successful closure outcomes for mine sites, as well as the TSFs on those sites, will differ significantly from mine to mine. However, three core concepts underpin and support successful TSF closure: early planning, integrating closure considerations, and robust governance.

Early planning

The greatest opportunities to maximise mine closure outcomes exist before operations even begin. Considering closure from the earliest stages of mine development allows environmental, economic, and social elements to shape TSF design and location onsite, reducing the risks of unforeseen challenges and costs at closure. This also enables companies to evaluate whether a TSF is the best option for that site or whether innovative alternative approaches could better support a positive post-mining legacy.

Planning for closure and operating a TSF in a manner consistent with closure objectives are activities that crosscut the entire lifecycle. Closure and post-closure are often regarded as distinct phases of a mine’s lifecycle, however, each earlier phase of a mine’s life has direct influence on the ability to achieve desired closure and post-closure outcomes. This is particularly true for a TSF, which can undergo significant changes from its original design, such as when mining extends beyond initial plans or when ore processing requirements change due to variations in mineralogy within a deposit.

Integrating closure and post-closure considerations into TSF design

Integrating closure considerations at every stage of TSF design or modification is critical, as is incorporating any variations to the TSF into site-wide closure plans. This ongoing monitoring and reviewing of closure and TSF plans throughout operations can also create opportunities for progressive closure activities relating to the TSF.

Progressive closure involves the implementation of closure activities during the operating life of a mine. It provides opportunities to test and demonstrate the effectiveness of closure activities, validate closure success criteria, and incorporate learnings into closure planning while there is maximum flexibility before operations have ceased.

Robust governance

Robust governance is the cornerstone of effective TSF management, ensuring safety, stability, and environmental protection throughout a mine’s lifecycle. From design to closure and post-closure, strong governance frameworks establish accountability, enable informed decision-making, and foster collaboration between tailings and closure professionals.

While closure objectives may vary by site, one ultimate goal remains consistent: creating a safe, stable, and non-polluting facility that aligns with designated post-closure land use plans. Strong governance frameworks establish clear accountability and foster collaboration across disciplines, enabling operators to proactively identify and mitigate risks, optimise resource allocation, and align closure plans internal to the mine and externally with stakeholder needs.

The transition from an active TSF to a successfully closed one hinges on governance, which ensures that closure-related outcomes – such as environmental protection, community safety, and sustainable land use – are achieved effectively and responsibly.

Conclusion

The mining industry has recently turned an innovation corner, with growing R&D efforts aimed at a future without mine waste and without the need for TSFs. A future of mining without waste is an exciting vision, driven by mining professionals prioritising closure at the forefront of mine planning and innovation – a marked shift from past practices.

However, until the industry achieves waste-free mining, the closure of TSFs must remain guided by three core principles: early, integrated, and robustly governed. Mine closure is increasingly challenging and costly for operators, with more mines closing than ever before. Closure will always involve a push-and-pull between short-term operational profits and managing long-term liabilities. Yet, the opportunities for communities, ecosystems, and human safety – achieved not just through effective closure but by delivering post-mining benefits – are too significant to delay planning until post-production.

Innovation is indeed steering the industry closer to a future without new TSFs, but achieving this vision will depend, among many factors, on operators embedding closure considerations from the design phase and maximising integrated closure activities throughout the asset’s lifecycle. The path forward is clear: prioritise closure today to unlock a sustainable tomorrow.

Read the article online at: https://www.globalminingreview.com/handling-processing/21032025/closing-the-gap-integrating-tailings-storage-facility-closure-into-mine-lifecycle-planning/