With approximately 80,000 mines sitting abandoned across the country, Australian Mining takes a look at the different ways these sites can be rehabilitated.
Mines, like most resources, are finite things. Once all of the ore has been extracted, it’s time to close up shop, rehabilitate the area, and move on to the next site.
Nowadays, there are fortunately stringent rules and regulations that must be followed when a mine closes. But these rules didn’t start to become commonplace in Australia until the 1980s, which leaves a considerable gap given the country’s mining history spans more than two centuries.
This shortfall has led to approximately 80,000 inactive mines sitting unused across the country, and many of those are left over from the days of the Victorian gold rush in the 1850s.
“Closed and abandoned mines can pose a threat to health and safety,” Global Soil Systems general manager James Nebauer told Australian Mining.
“They can have minimal or no security, and there are a variety of hazards including voids, mine shafts, highwalls, water bodies, and old and unstable structures and buildings.
“By rehabilitating and reforesting the land, it can help to mitigate these negative impacts and support the restoration of the surrounding ecosystem.”
Nebauer discussed some insights his company has gained throughout its long history of mine rehabilitation.
“From an environmental perspective, degraded land poses a significant risk,” he said.
“Displacing native vegetation during the mining process can have negative environmental consequences, including soil erosion and loss of biodiversity and habitat.”
Nebauer said that creating a self-sustaining ecosystem on a mine site can take years, but the results are worth it.
“When done correctly, the final result can blend seamlessly with the surrounding vegetation and it can even be difficult to distinguish what was once mined land versus what is remnant vegetation.”
While rehabilitating tens of thousands of sites may seem like an impossible task, governments, regulatory bodies and specialist teams remain hard at work to restore the land these mines once called home.
To learn more about these rehabilitation efforts, Australian Mining examines two of the largest abandoned mines in the country, along with smaller programs that are making sites across the country safer.
Ellendale
Arguably one of the most famous abandoned mines in Australia, the Ellendale diamond mine sits 140km east of Derby in the West Kimberley region of Western Australia.
The mine produced fancy yellow and white diamonds from the time it opened its doors in November 1976 to its eventual closure in July 2015. These gems were reminiscent of those produced at Rio Tinto’s Argyle diamond mine and Ellendale was, at one point, the source of up to 50 per cent of the world’s supply of fancy yellow diamonds.
But all good things must come to end, as the diamond world found out when Ellendale was closed following the liquidation of its owner, Kimberley Diamond Company. The mine was declared abandoned and a liquidator’s auction disposed of the valuable items of plant and infrastructure associated with the site.
While some infrastructure was removed, unsold items were left to sit and the site is currently undergoing active rehabilitation through the WA Department of Mines’ Mining Rehabilitation Fund (MRF).
The rehabilitation of Ellendale is currently in its second phase, with the MRF working with the community and stakeholders to minimise the site’s safety, health and environmental risks.
Benambra
While some abandoned mine sites undergo a full rehabilitation, there are those that have a little more life left in them.
Such is the case with Benambra, a former copper-zinc mine in East Gippsland, Victoria.
Benambra was active from 1992–96, when the mine was placed into administration following its operator defaulting on its environmental rehabilitation obligations.
While the Victorian Earth Resources Regulator has been looking after the maintenance and rehabilitation of Benambra since that time, the mine is now the site of a development project by mid-tier miner Aeris Resources, which acquired the project in July 2022 through its acquisition of Round Oak Minerals.
Named the Stockman project, Aeris plans to develop two new underground mines at the site to mine zinc, copper, gold and silver.
“Aeris will be focused on delivering the operational targets across the expanded operating portfolio, continuing our aggressive exploration program and finalising the feasibility study for the Stockman project,” Aeris executive chairman Andre Labuschagne said in 2022.
“Aeris is well positioned to deliver our organic growth pipeline with a strong cash position and no debt.”
In its 2023 annual general meeting, Aeris reported the feasibility study at Stockman had progressed throughout the year, its mining license extension had been approved, and all licensed tailings dams were in place.
Given they are among the largest abandoned mines in Australia, Benambra and Ellendale have each benefitted from having large teams of people bring them up to code.
But that size and level of personnel is the exception rather than the rule.
Most of the 80,000 abandoned mines in Australia are nothing like these mines. In fact, the majority are small shafts left over from the mining boom of the mid-1800s.
In order to make these shafts safer, specialist projects had to be drawn up.
Safer shafts
With so many mine shafts pockmarking the Australian landscape, it was only a matter of time before they posed a risk to the rapidly expanding communities in the surrounding areas.
In response, the MRF developed the Safer Shafts for Towns project in 2022, focusing on communities like Yalgoo, Cue and Marble Bar in WA that had abandoned sites located close to schools.
The ultimate goal of the project is to reduce the risk to any child that may be exposed to an old mine shaft.
While the Safer Shafts for Towns project is currently being assessed and evaluated to inform further development before it is rolled out to other regional communities, researchers at Melbourne’s Monash University have introduced a program to help catalogue and eventually rehabilitate old mine shafts.
Dubbed the Mining Incidence Documentation and Assessment Scheme (MIDAS), the program is used to catalogue and compare active or inactive mine data. MIDAS uses geographic information system spatial analyses and environmental risk assessments to show the proximity of shafts to infrastructure and environmental receptors.
“As Australia struggles to manage the ongoing technical, socioeconomic and environmental challenges of effective mine rehabilitation, the insights enabled by this national-level spatial database may be key to developing coordinated responses that extend beyond state boundaries,” the creators of MIDAS said in their report, ‘A Geospatial Database for Effective Mine Rehabilitation in Australia’.
“Our classification and methodology are easily transferable, thereby encouraging more formalised, systematic and widespread documentation of abandoned mines worldwide.”
Whether they be large open pits or smaller shafts, abandoned mines pose safety and environmental risks. But these risks can be mitigated.
Through strict legislation, stringent environmental processes and a healthy dose of exploration, abandoned mines can truly get a new lease on life.
This feature appeared in the February 2024 issue of Australian Mining.
