It's often said that Australia is a nation built on mining - from the gold rushes that started in the early 1850s and continued for decades later, to present day Australia, where mining is the biggest contributor to the country's GDP.
This history of mining, however, has left a legacy of an estimated 50,000 abandoned mines that a more environmentally-conscious age demands be rehabilitated and restored. Abandoned mines degrade local environments and create hazards for local communities and animals. In some cases, the mines were home to rare plant species and now a detailed restoration plan is required to re-cultivate. Furthermore, water high in metals can pollute the surrounding environment; in 2013 cyclone Oswald caused wastewater from around 20 Queensland mines to rush into passing floods.
Rehabilitating these mines, many of which were abandoned before an environmental bond was required for their rehabilitation, has been a challenge. Often, portioning responsibility for rehabilitation of historical mines can be complex or fall solely on the state. Rehabilitation is also a lengthy and costly process; often the upfront environmental bond required to be paid by a mining company before undertaking a mine becomes insufficient after its closure as environmental standards, and costs rise.
Nevertheless, environmental activists and the industry, which views abandoned mines as negatively impacting the industry's image and future licences, are in agreement that the issue urgently needs addressing.
According to the Queensland Government, which alone has 17,000 abandoned mines - an estimated 3,500 on public land and 12,500 on private land - a mine is classified as abandoned or orphaned when a mining tenure no longer exists and there are no legal avenues requiring the company, or individuals that created the mining disturbance, to carry out remediation.
However, the definition varies from state to state. And, despite a non-legally binding national policy, there is currently no national government agency with statutory responsibility for remediating abandoned mines, and each state or territory is independently responsible.
This, experts say, is one of the country's key failings when dealing with this growing problem.
A better understanding of the failure of materials could help engineers design against material collapse.
"What we would like to see is a national approach," Professor David Mulligan from the Centre for Mined Land Rehabilitation at Queensland University told ABC's RN breakfast show last year. "If we have some consistency, even in definition, and through that we can get some consistency in the risk framework that we can develop - that we need to develop."
Mulligan's colleague at the centre, Corinne Unger, agrees: "If national policy was implemented then we might see acceleration in maturity. At the moment we are a bit all over the place."
In a separate interview, Unger says, "Each state is at its own level of maturity with many jurisdictions simply reacting to legacy issues instead of addressing key obstacles relating to regulation and management of these sites."
As an example, she says: "Queensland mines safety department had responsibility in Queensland. However the environment department, DEHP, are yet to regulate environment impacts from abandoned mines."
Abandoned mines also represent significant financial liabilities for state governments and they must manage their budgets accordingly. Unger says many states are not "fully accounting for there liabilities".
The Northern Territory Government's liability for abandoned mines is estimated to be A$1bn. In Queensland a 2012 report estimated abandoned mines liability at $1bn, which Unger says is not recorded in the states' accounts, according to the Queensland auditor general.
These figures are merely estimates and the actual cost could be much more, depending on what is needed for the mine.
For example, a simple single mine shaft, which is believed to make up the majority of abandoned mines, is likely to be much cheaper and easier to rehabilitate than a whole mine such as Mount Morgan, which was once the largest gold mine in the world. The mine was transformed into a tourist attraction. After some time water from the mine, which had elevated levels of copper, aluminium, magnesium and other metals, leaked into the nearby Dee River - to this day the site requires constant maintenance.
To pay for the clean up of its abandoned mines Western Australia launched a new Mining Rehabilitation Fund (MRF) in 2012, which is a pooled fund that will be used to rehabilitate abandoned mine sites in the state. All tenement holders operating on Mining Act 1978 tenure are required to contribute annually to the fund, the interest of which will be used for abandoned mine remediation. A$30m has been paid into the fund since it was started, according to WA mines and petroleum minister Bill Marmion.
It is also hoped this approach will help mitigate mines being abandoned in the future by encouraging companies to progressively rehabilitate their mines, which "provides the best and most cost-effective environmental outcomes," according to Association of Mining and Exploration Companies (AMEC) CEO Simon Bennison. This approach will also help guard against companies going bust and leaving an abandoned mine they can't pay for, as the bond isn't paid up-front but throughout the life of the mine.
AMEC has been advocating for New South Wales (NSW) to introduce a similar mining rehabilitation fund model.
Environmental group Lock the Gate, however, has called for NSW Resources for Regions program, which puts mining royalties into community rehabilitation to be used for mine rehabilitation, as well as community infrastructure projects, to speed up mine remediation in the region.
The state has been making slow progress rehabilitating its abandoned mines. For example, between 2012 and 2013, 30 project sites were rehabilitated; the year before, 25 were rehabilitated.
At the national level, campaigner at Lock the Gate, George Woods, says he would like to see an establishment of a Rehabilitation Fund, administered by the federal government, into which companies contribute every year, which can then be used to pay for the clean up.
The South Australia Government has put in a slew of initiatives to kick start its struggling exploration sector, but is it doing enough?
Working together to solve a shared problem
While each state is trudging along with its own abandoned mine remediation plan and getting nowhere fast, if they pooled their resources and were overseen by government they could achieve much more, say experts.
A 2013 report by AusIMM encourages greater information sharing between the mining industry, governments and research institutes because, it states, data is key for understanding which challenges - including environmental challenges and health and safety hazards - lie ahead.
"If more widely shared then greater rigour in review is possible, creating opportunities for problem solving and innovation," the report states.
Quality of data, again, varies widely between states, with Western Australia believed to have the most comprehensive and Queensland and Northern Territories lacking behind. A better national approach would, it is hoped, bring states up to the same standard.
A review from the Centre for Mined Land Rehabilitation, presented at last year's Life of Mine conference, suggests that Australia draw upon leading practices in Canada where the National Orphaned and Abandoned Mine Initiative provides support across federal and provincial jurisdictions through an advisory panel of industry, government and the community.
This is something half of survey respondents for a 2013 report into abandoned mine rehabilitation - conducted by Unger and members of the AusIMM Sustainability Committee - said they would be in favour of.
In Canada and the US there are also projects specifically focussed on addressing legislative obstacles for abandoned mine rehabilitation from which Australia can learn.
Not just a liability
When considering an abandoned mine remediation approach it is important to view mines not just as a liability and burden, but as an asset.
"Integrating mining heritage tourism with rehabilitation also provides an opportunity for interpretation of historic mining activities and socio-economic benefits to the community at large," the 2013 AusIMM report states.
Examples of this are evident in many small mining towns and more significant sites, such as Mount Morgan and Broken Hill.
Unger's report also warns that mines should not just be viewed as potential future mines, either. This encourages governments to "wait and hope that a mining company take over the liabilities".
But for Unger there's one key solution that could galvanise the seemingly insurmountable problem - and that's national leadership.