By Samantha James
THE inevitable mothballing of coal mines around the world will force the industry to question who is responsible for the rehabilitation of the abandoned sites, and what best practices can reduce the long term impact on native environments.When left untended, open pits below groundwater level fill with rain and groundwater to become pit lakes, and large regions with abandoned, un-reclaimed areas turn into lake districts.
Above groundwater, pits are left as large holes in the landscape known as final voids; they prevent rehabilitation of native plants and animals or reuse as agricultural land.
NSW is feeling the impact of final voids keenly, with more than 500 derelict mines across the state. Further issues are anticipated with the closure or expansion of another 20 to 40 mines between Singleton and Muswellbrook in the Hunter Valley, expected to create a lake district across the 48km region.
A report by the Planning and Assessment Commission in March 2015 called for a study to be undertaken by the Department of Planning and Environment to review the cumulative impact of voids in the region.
Since 2011 the Tom Farrell Institute for the Environment (TFI) has hosted the annual Mined Land Rehabilitation Conference (MLRC) in NSW, bringing together a range of community stakeholders to discuss best practices in mine rehabilitation and reclamation.
TFI director Dr Tim Roberts said that as the science and attitudes behind rehabilitation constantly evolved, so did the conference, to reflect the bigger picture in reclamation and its impact on future landscapes.
Expanding focus
Interest in the science behind land rehabilitation at the conclusion of mining has increased since the inaugural MLRC, resulting in a change of venue for the 2016 event to cater for a larger crowd of about 500 delegates.
Dr Roberts started the conference to bring to the attention the rehabilitation research and development work being done by the team of ecologists at the University of Newcastle and to create a dialogue between researchers, regulators, miners, professional rehabilitators and the local community.
“In 2011 there was little recognition of the huge amount of land that would need to be rehabilitated in the Hunter Valley; the regulation regarding rehabilitation was constantly changing,” he said.
“Back then I wanted to create a dialogue between stakeholders, but the conference serves a broader purpose now.
“Initially it was just concerned with best practice in an ecological sense to get the vegetation to regrow, but the focus has expanded as a lot of the rehabilitation is now aimed towards an agricultural purpose, rather than re-establishing a certain endangered species or a particular ecological community that was wiped out during the mining process.”
Dr Roberts said that although the conference still addressed best methods of vegetation and animal rehabilitation, it had grown beyond that as a result of expanding interest and issues.
“Last year we had a panel session about what to do with the voids that will be there when mines are closed, and that was part of the evolution of understanding,” he said.
“Back in 2011 I don’t think any of us realised we would have so many pit lakes between Singleton and Muswellbrook occupying a significant number of hectares.
“The evolution in concepts over the five years has meant we discuss the bigger picture.”
Topics that will be covered at the 2016 conference include soil symbiotic microbes – bacteria and fungi that are closely associated with plant roots and necessary for the uptake of nitrogen and phosphorous to promote growth; final voids in the Hunter Valley – a focus on the practical rehabilitation and the legislation surrounding the responsibility of final voids; and discussion of what other countries have done to combat growing rehabilitation problems with the rapid closure of mines around the world.
International researchers from Poland and Indonesia will also attend to “expose delegates to the latest research and development in rehabilitation”.
Dr Roberts said the MLRC provided a platform for bringing together competing perspectives.
“We don’t provide a platform to argue in a political sense between the positives for miners and the negatives against mining, so we think it’s one of the most significant outcomes,” he said.
“We’re able to ask the question, and examine the question, of what the mined lands will look like after completion and what is lacking in getting desired outcomes.”
In 2015 a mine tour was added to the conference to help convey the enormity of ongoing rehabilitation work and for the success and failures of existing programs, science and research to be experienced firsthand.
“Direct interaction helps to find holes in the system – revealing what is working and what isn’t – and opens up a space for discussion,” Dr Roberts said.
“The major need at present is to understand what the land will look like once all the mines are completed, and it looks like we’ll have a whole lot of pit lakes or water bodies, so we have to plan how to react and understand them. This is part of the evolution of the conference.”
International voids
Final voids have been an international concern for more than 40 years; in 1977 the US took action after years of failed rehabilitation methods, implementing the Surface Mining Control and Reclamation Act (SMCRA), a federal law that regulates the environmental effects of coal mining.
Australia has no such law, meaning that standard rehabilitation practices and regulations vary across the country.
Dr Roberts said that although a new Integrated Mining Plan for NSW was due to be released in 2016, which “should ensure that there is money for rehabilitation after mining finishes”, he believed Australia should already be using the SMCRA as a model.
“We certainly have a better understanding of the mine rehabilitation process, and better regulation of the process in Australia, due to the focus on rehabilitation in the past five years,” he said.
“Unfortunately we do not have uniform laws across the various states and this is in itself a barrier to future mine rehabilitation.
“My goal would be to have the federal government implement a law similar to that enacted in the US.”
SMCRA created two programs: one for regulating active coal mines and a second for reclaiming abandoned mine lands.
The regulation of active mines under SMCRA has five major components – standards of performance permitting, bonding and inspection and enforcement.
Dr Roberts said bonding required mining companies to post a bond sufficient to cover the cost of reclaiming the site.
“This is meant to ensure that the mining site will be reclaimed even if the company goes out of business or fails to clean up the land for some other reason,” he said.
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“The bond is not released until the mining site has been fully reclaimed and the government has (after five years in the east and 10 years in the west) found that the reclamation was successful.
“However, the US is finding that even though they have this law, companies that become bankrupt still have the capacity to leave rehabilitation in the hands of the general public.
“We can take these issues and discuss them in response to our own experiences here in Australia.”
Rapid uptake
Dr Roberts said that the uptake of new technological solutions in relation to rehabilitation had been rapid, and technology presented at past conferences implemented at rehabilitated mine sites across the country.
He said that in the past few years the use of remote control helicopters for surveying vegetation regrowth, pollen analysis to determine plant biodiversity, and several software programs to monitor and survey progress had been implemented at Australian sites.
“From the conference I think there’s been more interest in terms of the regulators trying to achieve connectivity of vegetation between the mines,” he said.
“The mines in the past have been operating independently, but through this kind of dialogue they’re starting to talk to each other and have connected patches of regenerated land to create a migration corridor for birds and other animals.”
A major drawcard for the conference is its networking focus; a long lunch break and morning and afternoon teas are designed to encourage collaboration, interaction and cross-disciplinary discussion.
“For me the knowledge outcomes are the important things,” Dr Roberts said.
“The positive outcomes come in the knowledge exchanges that are possible from the conference, and new possibilities, partnerships, research grants and programs.”
