While a number of coal mines in the Upper Hunter are seeking to extend their productive lives others are approaching mine closure, and it is this 'end-of life' transition for the mines that will require crucial management.
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The mining transition is now being talked about, often in terms of future jobs and economic impacts, but how the estimated 50,000 hectares of mine buffer lands and the nearly 30 final voids are rehabilitated is just as important for the future of the region.
Currently in the Upper Hunter four open cut mines have ceased production, they are: Ashton North East (2011); Drayton (2106); Muswellbrook Coal (2022); and Liddell (2023). One underground mine Integra, will also cease production at the end of this year.
The next expected mine closure is BHP's Mount Arthur near Muswellbrook which will cease production in 2030.
So how long will rehabilitation take and what are regulations surrounding this work?
Given the fact Ashton North East located near Camberwell closed 13 years ago and Drayton near Muswellbrook closed eight years ago we asked the Department of Regional NSW if the sites had been certified as being rehabilitated - a condition where the government is satisfied that the final landform is safe and stable post-mining.
The Department's response was rehabilitation is ongoing at both Ashton North East and Drayton (now Maxwell Underground) mines.
"The Resources Regulator maintains its regulatory oversight at both of these mines and will continue to maintain a security deposit until the rehabilitation obligations have been fulfilled," they said.
That means, to date, no mines in the Upper Hunter have received a final tick of approval for their completed rehabilitation from the regulators, which would suggest it may take decades for rehabilitation to be completed at these mine sites.
Greens MP and mining spokesperson Cate Faehrmann said:
"The lack of transparency around what coal companies are required to do and by when in terms of mine rehabilitation is completely unacceptable. Much of the Upper Hunter landscape is scarred as far as the eye can see with massive open cut coal mines and the community deserves to know has been committed to when it comes to restoring the site to as much of its prior natural state as possible.
"Coal companies like to talk up big when it comes to rehabilitation when they're seeking approval for mining projects, yet there's very few, if any, examples of a successfully rehabilitated mine in this state.
"The Minister needs to whip her department into shape and guarantee to the community that there will be greater transparency around mine closure plans and the rehabilitation efforts of mining companies going forward."
In response the Department said "It is a requirement under the Mining Regulation that rehabilitation is undertaken as soon as reasonably practical and must achieve the designated final land use as set out in the development consent for a mine.
"Rehabilitation progress is tracked through the Annual Rehabilitation Report and Forward Program and is inspected routinely through the Regulator's inspection program.
"Rehabilitation at mine sites can take time. The Department won't finalise and approve rehabilitation until it is satisfied the mine's owner has completed the necessary work."
One of the questions being raised is what to do with final voids? When some of these mines went through the planning approval processes their mining operational plans for closure involved using either water from tailings dams and or fill from adjacent mining operations or from new mining extensions. There was no great detail about the final voids in those closure statements.
In fact it was only in December last year that the NSW Resources Regulator actually included a formal definition for a final void in its Guideline 'Rehabilitation Objectives and Rehabilitation Criteria'.
Final void (the extent is defined by an area that does not free drain to the surrounding surface environment)
The lack of details about the voids in the final landform has led to plenty of ideas being suggested including pumped hydro (Muswellbrook Coal) and a series of lakes similar to those in the Lusatian Lake district of Germany.
However the depth (300metres), size (more than 1000ha), toxicity and soil types of the Upper Hunter voids could well preclude such a lake development.
The Department says it is working closely with many mines in the Hunter about technical aspects of closure which must be finalised to inform the completion criteria. The Department is satisfied that adequate work is occurring to enable safe and stable rehabilitation for mine closure.
The Department says Integra mine is continuing with rehabilitation of the mine site. A completion criteria statement will be required to be lodged with the Department once rehabilitation is scheduled to achieve the final end land use, which is not usually the same time as a mine site ceases production. The Resources Regulator will continue to monitor the Integra mine to ensure progressive rehabilitation of the site.
A statement from the Department given to the Singleton Argus lists their guidelines which are intended to provide advice on rehabilitation, but the obligation to progressively rehabilitate a mine site and submit completion criteria is set out in the Mining Regulation. This requirement is as follows:
1. submission of a Forward Work Program which outlines the rehabilitation that will take place over the next 3 years.
2. Submission of final rehabilitation completion criteria when the Forward Work Program envisages completion of rehabilitation during the period. In other words, a completion criteria statement is required to be lodged with the Department when rehabilitation is scheduled to achieve the final land use.
The rehabilitation completion criteria statement must be approved by the Department.
It can take several years after the closure of a mine for rehabilitation to mature to a standard that the Resources Regulator determines meets the final land use. This means that a rehabilitation completion criteria statement would not typically be submitted to the Department until after a mine ceases production.
The Resources Regulator closely monitors rehabilitation at mine sites and takes compliance and enforcement action when regulatory requirements are not met.
The Regulator is working with a number of mining companies to ensure that rehabilitation completion criteria statements are developed on the basis of robust scientific principles to ensure long term sustainable rehabilitation outcomes.
Louise Nichols
From cattle to coal. Once a specialist agriculture writer today its about community, in particular, the Upper Hunter. I have lived and worked in the region for more than 30 years. Land use issues and the future direction of our region. But you cannot take ag out of the picture - our food and how we grow it is the basis of all life. Covering the Hunter and Mid North Coast rural issues is now part of my role with ACM.
From cattle to coal. Once a specialist agriculture writer today its about community, in particular, the Upper Hunter. I have lived and worked in the region for more than 30 years. Land use issues and the future direction of our region. But you cannot take ag out of the picture - our food and how we grow it is the basis of all life. Covering the Hunter and Mid North Coast rural issues is now part of my role with ACM.
