Mine rehabilitation is a legal requirement in Australia that is governed by state and national laws. Over the past 2-3 decades, these have helped to establish long-term environmental standards.

As with many sustainability objectives, however, rehabilitation expectations are evolving.

Companies – and their diverse stakeholders – are coming to understand that the best possible outcome may not always be ‘putting a site back to the way it was’.

In some cases, there are opportunities to transform sites, enhance biodiversity and significantly improve outcomes for post-mining land use.

Working progressively

Progressive closure is now widely considered leading practice across the resources sector, supported by the global Integrated Mine Closure: Good Practice Guide.

Put simply, ‘progressive’ means closure work is conducted throughout the life of a mine.

Bauxite mining lends itself particularly well to progressive rehabilitation, due to its shallow, but expansive, footprint. Throughout the life of a mine, operations move across the land. Once production is complete in one area, rehabilitation can begin.

Julian Farrugia, project director at the Aurukun Bauxite Project, says rehabilitation planning is a major component of Glencore’s strategy for the greenfield site.

“Rehabilitation is a focal point,” he says. “We are consulting closely with community.”

Cameron Woolla, a Traditional Owner of the Wik and Wik Waya people of Aurukun, works as a specialist for operational readiness at the Glencore project site.

“Our Traditional Owners are inputting into the future plan for Aurukun now. We are making sure things are done properly from the outset, including documenting every plant and animal species.

“Once a bauxite mine is operational, rehabilitation work should begin straight away. Activities like seed propagation and environmental monitoring lay the foundations for later activity,” he says.

At the South32 Worsley Alumina Boddington Bauxite Mine, progressive rehabilitation is core to their science-led approach.

Environmental research in areas including biodiversity dynamics and species conservation, topsoil management and seed germination, and the importance of local provenance species have all translated into practical program updates.

Long-term rehabilitation also supports operational resilience, as Worsley Alumina is able to have regard to community feedback and embed evolving sustainability principles into their work.

Restoring ecological and cultural values

As well as regenerating individual species, rehabilitation also concentrates on restoring ecological and cultural values. This means understanding how all the environmental elements interact and using First Nations knowledge to guide priorities.

Travis Ryan, environmental advisor for Metro Mining, says this was the case at a legacy mine in their portfolio.

“Our Bauxite Hills lease, north of Weipa in western Cape York, included an abandoned kaolin mine from a previous incumbent, where a culturally significant and environmentally sensitive creek system was being impacted.

“We delivered rehabilitation including bulk earth works to re-establish the original creek line, creation of a seed bed, and erosion and sediment control. We were able to source seed from our community seed collection program.

“Obviously, regeneration takes time. But the important thing is that we have begun re-establishing the area’s important values. And we are transferring all our learnings to our own operating bauxite mine.”

Enabling new purposes

Progressive rehabilitation also enables everyone to optimise opportunities for future land use.

Mark Cooksey, managing director and CEO of ABx Group, says that from the beginning of a new bauxite mine, they focus on the outcomes desired by land owners and stakeholders.

“If your goals are clear, you can plan and operate in a way that will maximise those benefits. If you wait until the end, it might be too late.”

Nathan Towns, national operations manager, based at ABx’s Tasmanian projects, emphasises that these benefits can go beyond returning the environment to its former state.

“There tends to be huge variability in the condition of the land where bauxite is found. At our sites, we often see rocky topsoil, for example, which isn’t suitable for crops or plant or forestry growth.

“This can also mean native animal habitats aren’t present or aren’t in great condition.

“Without mining, the cost of upgrading this land wouldn’t be feasible”, Mark explains. “When we all work together, we can achieve new purposes – be it agriculture, tourism or conservation.”

“A living laboratory”

Progressive rehabilitation also fosters circularity and continuous improvement across mine life.

Lucy Commander, research manager for the Alcoa Forest Research Centre, describes Alcoa’s operational sites as “a living laboratory”.

“While we have a physical building at our largest bauxite mine, Huntly, our ‘research centre’ is a program of works across our mine sites and in the forest alongside our network of collaborators.

“This ensures we are close to the real challenges the business is trying to solve.”

Alcoa has committed $15 million to research over 5 years, covering 5 pillars: rehabilitation, fauna protection, flora knowledge, water stewardship, and First Nations 2-way science.

“The methods used in rehabilitation make a big difference to the outcomes and they have always been a core focus of our research,” Lucy says.

“For example, our research as early as the 1970s led discoveries in double-stripping and direct return of soil – which means taking both a top and lower layer of soil from sites before operations commence – to return the soil seed bank and enable plant regeneration.

“We also developed machinery to assist with soil ripping – intentionally breaking up the soil to alleviate compaction and allow water infiltration – in the 1980s, nurturing forest re-growth.

“Later, a lot of good work was done to rehabilitate fauna using salvaged coarse woody debris. This can be put back after mining to allow animals to take refuge and burrow while waiting for trees to grow.

“And, of course, these days we understand the importance of using local native species in rehabilitation. So much science goes into seed sourcing and germination to deliver results.”