Why safe mine closure is just the beginning and not the end of the story for mining companies, communities and the land they leave behind

If there was one thing the panel on safe mine closure made clear at this year’s Life of Mine - Mine Waste and Tailings Conference in Brisbane, it’s this: closure is no longer just about sealing off the last truckload and planting grass. It's about what comes next - and who carries the responsibility.

Facilitated by South32’s principal tailings governance specialist Ina Prinsloo and Rio Tinto’s manager SME major hazards Fernanda Maluly Kerneid, the expert panel brought together diverse voices across engineering, social performance, land rehabilitation, and environmental science. What emerged was a rich, at times provocative, and ultimately constructive discussion on what "safe" really means - and whether it’s even the right word.

Rethinking “safe” as “responsible”

For Theo Gerritsen, principal engineer at BGC Engineering, the term “safe” is part of the problem.

“In practice, we encounter this expectation that safe means we can walk away, and it’ll look like nothing ever happened,” he said. “But after 30 years in tailings and mine waste, I’m convinced that’s rarely achievable. Instead, we need to talk about responsible closure - closure that accepts there are residual risks and incorporates ongoing maintenance into the equation.”

Theo pointed to infrastructure analogies - bridges, airports, roads - as examples of engineered systems that society accepts require upkeep.

“We maintain all sorts of things as a matter of course. Why not mine infrastructure?”

It’s a compelling argument. Many mine sites - especially legacy ones - may never reach a condition where risk is fully extinguished. As Theo framed it: “Can we really claim zero harm after putting chemicals through ore, processing it, and returning it to the environment?”

Closure is a beginning, not an end                                       

That sentiment found resonance with Rebecca Anderson, communities and social performance specialist for Rio Tinto’s Winu Project. Rebecca offered a social dimension to the engineering view - highlighting how traditional owners and local communities define success in entirely different terms.

“For traditional owners, risk doesn’t end when guidelines are met,” she said. “The relationship with the land, and with the impacts of mining, continues for generations. Closure has to reflect that.”

Winu is a greenfield copper-gold project in Western Australia’s Pilbara region. From the outset, Rebecca and her colleagues have taken a partnership-first approach - one grounded in free, prior, and informed consent.

“That means co-design, not just consultation,” she said. “We've gone through eight iterations of the TSF design based on direct feedback. Everything from its location to construction methodology to closure objectives has changed because of that process.”

It’s an effort Rebecca described as “walking alongside” traditional owners. And it’s clear the approach is reshaping not only the project’s footprint, but the company’s internal understanding of closure.

“There’s a strong emphasis on cultural and psychological safety - not just physical safety,” she explained. “We’re thinking in centuries, not decades.”

Closure lessons from landfills

From a different sector, SMEC Australia’s principal engineer Kate Beard brought lessons from decades of landfill capping and post-use planning - highlighting common challenges and offering caution against over-engineered promises.

“Our mantra has always been focus on closure obligations first. Post-use can come later,” said Kate. “Trying to predict the future is hard. I once capped a site that later became a hydrogen hub. Another was slated for a double-decker golf driving range - on 20 metres of squishy trash.”

Her point? Future land use is dynamic. Closure needs to lock in stability and low-risk outcomes but not get overly entangled in speculative repurposing.

Kate also questioned the industry’s default financial logic.

“I get the NPV thinking - defer closure, save capital. But that assumes construction costs rise with inflation. That’s clearly not what’s happening. Delaying often means you’re just making it more expensive and more complicated.”

Her recommendation: cap early, while costs and regulatory requirements are still manageable. And when seeking environmental approval, leave enough flexibility.

“I’ve been hamstrung more times than I can count by imaginary lines drawn too early. Approvals should define boundaries, not dictate design.”

Designing for landform evolution, not finality

For Tim Rohde, CEO of SGME and a closure veteran with over 600 projects under his belt, the conversation boiled down to one thing: realism.

“The industry is still clinging to the idea that landforms can be designed for eternity using small-scale lab tests and erosion models,” said Tim. “We’ve got to stop pretending that’s good enough.”

Tim called for broader data sets, site-scale monitoring, and catchment-scale planning that allows for adaptation and correction over time.

“It’s not about zero erosion. It’s about acceptable erosion - and the ability to change course if we get it wrong.”

Tim introduced the idea of designing with “trajectory” in mind: aiming to reduce risk and increase stability but leaving room for modification. He described successful closure as a “succession” of efforts, not a single point-in-time event.

“At first, it’s a managed environment. Later, it may become self-sustaining. But even then, someone needs to stay behind. Whether it’s the operator or the government, the idea of complete walkaway is still largely a fantasy.”

The vegetation myth

No mine closure discussion would be complete without a mention of revegetation - and environmental scientist Ingrid Meek, principal rehabilitation and reclamation specialist with Okane Consultants, didn’t shy away from the topic.

“We need to stop assuming vegetation will save us,” said Ingrid bluntly. “Revegetation can either help or hinder depending on how it's integrated into the overall landform and cover system design.”

She called for better alignment between ecological goals and geotechnical design, noting the tensions that often arise.

“Everyone wants a 20-metre native forest, but don’t puncture my liner!” she quipped. “It’s a design problem, not a wish list.”

Ingrid, who formerly led GISTM implementation at Rio Tinto’s closure sites, stressed the need to move beyond idealised end states and focus on integrated, iterative approaches.

“You can’t just plant some trees and walk away. Closure performance has to be monitored, adapted, and maintained - sometimes for decades.”

Is "safe closure" the right benchmark?

As the discussion wound down, a persistent tension remained. Should “safe closure” be the industry’s gold standard - or does it unintentionally imply finality?

“In my experience,” said Ingrid, “safe closure is a milestone, not an endpoint. It's a threshold that enables responsible relinquishment, but it doesn’t mean all the work is done.”

Fernanda, who co-facilitated the panel, offered a thoughtful synthesis.

“Safe closure means there are no material risks to people and the environment. That’s an important step - but it’s just that, a step. From there, we can build toward what successful closure really means.”

That broader vision, Fernanda noted, includes social, environmental, and technical criteria - and acknowledges that some sites may never fully relinquish risk.

“I think it’s more honest to recognise when a site will require in-perpetuity care,” she said.

The takeaway: closure is a generational commitment

If there was a unifying theme across the diverse perspectives, it was this: mine closure is not an engineering problem to be solved at the end of life. It’s a cultural, technical, financial, and social process that begins on day one - and extends across generations.

As Rebecca put it, “Closure isn't about ticking regulatory boxes. It’s about honouring relationships - to land, to people, and to the future.”

And in that light, “safe” is no longer enough. The real challenge lies in designing for change, embedding care, and being bold enough to let go - without walking away.