According to Geoscience Australia, there are approximately 400 operating mines, producing 19 minerals in significant amounts, in Australia. At some point, these mines will be required to undergo rehabilitation, either during the operation or afterwards in accordance with environmental approvals.
The challenge may seem Herculean; however, a group of professionals in the space say that better collaboration, communication and innovation are steering the industry onto the right path.
According to Gavin Lind, Acting CEO of Minerals Council of Australia (MCA), mining companies understand that land rehabilitation is fundamental to responsible mining.
“Mine rehabilitation is highly regulated, better implemented and more accountable than ever before,” said Mr Lind.
“Planning for rehabilitation takes place long before mining commences, and rehabilitation is undertaken progressively during the life of a mine wherever practical. The minerals industry is committed to the rehabilitation of mined land and to make it available for other uses after mining, whether it be conservation, grazing, cropping or other uses.”
Effective communications are essential to the success of any mining project however, critics claim that confusion surrounding the definition and application of terminology in post-mining ecological repair has resulted in uncertainty for industry, the scientific community and regulators.
Historically, Australia, America and most jurisdictions have used the term rehabilitation as a broad term to encompass all the activities performed to improve land post-mining. In contrast, Dr Adam Cross, Research Fellow at the ARC Centre for Mine Site Restoration, Curtin University, prefers the phrase ecological restoration when it comes to revegetating mine sites.
Dr Cross says that rehabilitation aims only to achieve some form of recovery in landscapes that have been degraded and that the recovery activity can be something as simple as planting grasses or cereal for livestock grazing post-mining. In contrast, ecological restoration is the process of returning ecosystem functioning and biodiversity towards levels derived from some form of reference. The reference point could be based on a dataset gathered from the site itself before mining disturbance takes place, a neighbouring area of intact vegetation, or even some agreed-upon value. Many Australian mines aim to reinstate native vegetation following mining, and are actually undertaking ecological restoration rather than rehabilitation.
The Society for Ecological Restoration says that while we can successfully restore biodiversity, structure, and function to a degraded ecosystem, ecological restoration is not a substitute for conservation, nor should the promise of restoration be used to justify destruction or unsustainable use. The Society also warns that in reality, restoration may not succeed in re-establishing the full assemblage of native species or the full extent of the original ecosystem's structure and function.
Conversely, Tony Pekin, Director at Nurture Revegetation, sees rehabilitation as the early works such as earthworks and land forming.
“I consider revegetation as the very last step. It’s the icing on the cake.
“Revegetation may only comprise the last one or two per cent of the whole process. However, if the first 98 per cent is done correctly, but we fail to revegetate, then you haven't restored the land, which leaves it vulnerable to erosion.”
Dr Cross says that it’s vital that the mining industry is not hindered by the concept of returning biodiversity at all costs.
“Restoring biodiversity should be the aspiration, however, where there is evidence that it is not possible designing alternative uses for those mines is a great example of how miners can engage in a partnership with local stakeholders,” said Dr Cross.
He says that when miners plan for closure, they can prepare the end-use for that mine in consultation with all stakeholders to be almost anything. Examples from around the world include solar farms and grazing fields, and museums, amusement parks and hotels.
Both Cross and Pekin named the Argyle Diamond Mine as an excellent example of effective stakeholder collaboration.
The mine is set to fully close in late 2020, with owners Rio Tinto saying that complete rehabilitation will take between five to ten years. Before getting underway, Rio Tinto has been active in bringing traditional owners and regulators to the table. By adopting principles of environmental co-management, the Argyle rehabilitation program has so far:
· Introduced plant species of significant importance to local people into the rehabilitation areas
· Developed a small business enterprise within the two Aboriginal communities that provide native species seeds and seedlings for the rehabilitation process and for sale to other miners
· Created employment opportunities in horticulture-related activities for elderly people and women with children who are not able to gain employment outside the community
· Created employment opportunities for some community members within the Argyle operation itself
Rehabilitation requirements are specified in regulatory approval conditions. While the post-mining land use can vary, all states require previously mined land to be made safe, stable and non-polluting. Companies must regularly report on rehabilitation progress in line with their approval conditions, usually annually.
According to a Minerals Council of Australia spokesperson, State and Territory Governments require companies to provide some form of financial surety in the form of a bond before mining can begin.
These funds are generally intended to cover the full third-party costs of rehabilitating mine sites. This does not remove the obligation for companies to rehabilitate the land. Bonds are used only in the unlikely event those obligations cannot be met.
One of the criticisms of a bond-based system is that their level of security has not kept pace with the increasing costs and standards of rehabilitation.
In 1999 on any site in Western Australia, the bond represented approximately 80 per cent of the total cost of rehabilitation according to the WA Department of Mines, Industry Regulation and Safety. By 2008, that had dropped to around 25 per cent.
Bonds also lock-up capital with companies required to provide either cash or asset backing for the full amount in addition to paying direct costs such as annual fees and legal costs.
For smaller operators that are required to provide cash-backed bonds, they were required to pay the bond upfront, and then spend the rehabilitation costs, before applying to have their initial bond retired, and the cash returned to them. This essentially required the value of the bond to be paid upfront twice.
These findings led the Western Australia Government to introduce a new form of mining security in the manner of an annual levy to be paid into a Mining Rehabilitation Fund (MRF). West Australian regulators ‘can’ still require a bond, but it is not mandatory as in other states. The MRF is a first for the Australian Mining industry.
As at 30 June 2019, money in the fund totalled over $150 million, including net interest. On top of providing rehabilitation surety, the MRF also funds WA's Abandoned Mines Program.
Abandoned mines represent significant liabilities for state and territory governments, which are ultimately responsible for the costs associated with safety and environmental hazards resulting from these sites.
According to a report from the Senate inquiry into the rehabilitation of mining and resources projects published in March 2019, the cost of rehabilitating all major abandoned mine sites in Australia would run into billions of dollars. The committee also found that the liabilities associated with these sites are not consistently accounted for across Australia, and may be underreported.
“While it is claimed that there are more than 50,000 abandoned mines across the country, most are historic, single mine features including individual shafts, tunnels or mine workings (e.g. gold-rush era features around Gympie in Queensland, Kalgoorlie-Boulder in Western Australia and central Victoria) with few having material ongoing environmental impacts,” said MCA chief executive Mr Lind.
“Only a small handful of these mines are very large sites, and most of these sites were developed long before modern mining regulation. While this is an important issue to address, historic practices have little or no relevance to contemporary mining and regulation.”
Echoing these thoughts, Decipher chief executive Anthony Walker said that while industry challenges the actual number, everyone agrees that there are many abandoned mines in Australia and until recently, mine rehabilitation has been an afterthought for most mining companies.
"Decisions about mine closure in Australia have tended to have little consideration of how the land might be used post-mining. However, this is beginning to change, particularly with increased stakeholder pressure, environmental concerns and climate change discussions, and regulatory changes."
Mr Walker believes the entire industry has a responsibility to do better and implement best practice strategies and says Decipher plays an essential role in helping them achieve those best practices to drive progressive mine rehabilitation.
“We saw the opportunity to draw upon our knowledge, expertise and technology which had previously been used in the agriculture sector and share these learnings with the mining industry. As a result, we believe DecipherGreen could revolutionise the task of mine rehabilitation, closure and ultimately improve the rates of relinquishment of land – either back to Government or another organisation for use," Mr Walker said.
“It’s exciting and encouraging to see a cultural shift in the industry in recent years with an increased appetite for collaboration by industry, research bodies and government in this space.”
To leverage that appetite, Decipher has signed on as one of 70 partners supporting a bid for the establishment of a national Cooperative Research Centre for Transformations in Mining Economies (CRC-TiME) in WA, joining the likes of Alcoa, BHP, Rio Tinto, the WA, Queensland and Northern Territory Governments, as well as researchers from eight universities and the CSIRO.
CRC TiME chief executive designate and associate professor Guy Boggs is part of the bid team and outlined the potential benefits.
“The CRC-TiME would bring scale and coordinated investment to the world-class research being done in Australia, ultimately delivering transformational change to mine closure," Dr Boggs said.
"Over the next decade, we believe we would see a reduction in mine abandonment, an increase in relinquishment and an increase in the diversity of post-mining land uses. It also presents significant export opportunities for Australian companies."
Dr Cross’ ARC Centre for Mine Site Restoration is also a leading partner in CRC TiME, saying that the Centre co-wrote sections of the bid with director Kingsley Dixon being one of the leading figures in the proposal.
The ARC Centre for Mine Site Restoration in collaboration with government and industry also recently published the Framework for Developing Mine-Site Completion Criteria in Western Australia (badged under WABSI) – a world first and a document that will significantly help industry set completion criteria for mining projects.
Under the framework, completion criteria are defined in the mining context as agreed standards or levels of performance that indicate the success of rehabilitation and enable an operator to determine when its liability for an area will cease.
The New Hope Group have successfully rehabilitated approximately 490 hectares of mined land at their New Acland site, of which 240 hectares is now being used for grazing about 100 heads of cattle.
Glencore’s Rolleston open-cut coal operation in Central Queensland has also received certification on 400 hectares of rehabilitated mined land, representing almost 40 per cent of the total amount of mined land. Rehabilitation is incorporated into daily mine plans and annual plans to ensure that this work is resourced, budgeted and delivered. Such plans include target areas for disturbance, areas for shaping, seeding and forecasts for rehabilitation across the life of the mine.
In 2017, Nurture Revegetation was involved in a modest revegetation program that was conducted at the Nim Blue Waste Dump at Nothern Star’s Jundee mine.
The company has developed a pelleting process to improve the logistics of seed delivery and the survival and recruitment of seeds and seedlings.
Mr Pekin says that seeds are added to a bentonite clay mix before being formed into pellets. Additives to enhance survival are included in the clay mix and tailored to the targeted environment.
One of the challenges that mine sites experience is that it’s hard to time the distribution of raw seed. A lot of the seed is lost to the wind and predation. Plus, the seed needs to be scattered after the waste rock dump has been ripped but before the rain.
According to Mr Pekin, the company’s pellets substantially open the window of opportunity to apply seeds.
“The pellets can be distributed straight after the soil has been ripped and it doesn’t matter if it doesn’t rain for months because the pellets protect the seeds from the environment and from birds and insects.
Walker says that the product has been demonstrated at various sites in WA and has found that the pellets are well suited for use in drones.
“The major companies are very aware of their OH&S responsibilities and putting people on steep unsettled slopes is potentially dangerous. So, drones represent a way of the future,” said Mr Pekin.
The digital transformation has touched most areas of the mining industry, including rehabilitation. According to Decipher chief executive Anthony Walker, his company has been an early mover in the market.
DecipherGreen is a mine rehabilitation and closure planning platform that provides mining companies with the data, insights and tools needed to drive progressive rehabilitation, enabling them to implement best practice strategies and become industry leaders in this space.
“DecipherGreen utilises world-class technology including remote sensing, regulation technology, agriculture technology and environmental analysis to provide our clients with the data and insights they need to ensure they're meeting environmental obligations and compliance," he explained.
"As importantly it provides the information they need to plan for the closure and rehabilitation of their sites in a way that has a positive impact on their sustainability and social licence to operate, as well as the company's bottom line."
Decipher claims that users can easily track their rehabilitation efforts and commitments through the entire cycle by the platform.
Rehabilitation and new energy mines
New energy minerals such as lithium, nickel and copper are growing in significance as the world pivots towards a low carbon future.
Dr Cross says that these mines will face greater scrutiny of their proposed environmental impacts and rehabilitation and restoration strategies.
“This likely reflects the contemporary timing of these applications in terms of the social and regulatory expectations of the current day, rather than the specific expectations of these projects,” finalised Dr Cross.