Bowen Rail Company takes great pride in being a responsible environmental manager and how to rehabilitate the land used for the Carmichael Rail Network was a fundamental part of planning both the construction and operation of this greenfield rail corridor.
The approximately 200km Carmichael Rail Network crosses through the Brigalow Belt bioregion on its way from the Carmichael mine in the Galilee Basin to Aurizon’s Newlands railway line near Collinsville.
The bioregion is marked by semi-arid and tropical climates, through gently rolling hills and alluvial plains with shallow, stony soils.
Prior to a single piece of track being laid, environmental scientists had developed detailed plans that set out how Bowen Rail Company will return local ecosystems along the railway line to their original state – or better.
These plans are already in motion as the company undertakes regular monitoring of the environment surrounding the Carmichael Rail Network as well as the progressive revegetation of sites no longer required for operations.
The overall philosophy is to reinstate the rail alignment and associated infrastructure to pre-disturbance condition or an agreed alternate land use.
What is the Brigalow Belt bioregion?
The Queensland Brigalow Belt bioregion is a large and complex ecosystem that extends from west of the Great Dividing Range to Townsville and northern New South Wales.
A hardy, scrubby wattle, acacia harpophylla, is typical of the area. The Carmichael Rail Network goes through three sub-bioregions: Bogie River Hills, Northern Bowen Basin and Belyando Downs.
In the northern Brigalow Belt bioregion there are different ecologies and habitats, ranging from some remnant ecosystems, spinifex ridges, grassland, semi-evergreen vine thicket, acaciadominated shrubland, eucalypt woodlands, fringing riparian vegetation, coastal wetland, aquatic habitat and non-remnant cleared land.
Rehabilitating the rail corridor
Bowen Rail Company follows Queensland’s Department of Environment and Science hierarchy of rehabilitation. This guides the progressive rehabilitation of mines and major projects, and requires specific closure plans.
We expect our rail operations to continue for decades to come. However, when an area is no longer operationally required, areas no longer in use, such as camps and depots for the the construction phase of the railway, have already been rehabilitated.
This process included a risk assessment of all infrastructure and components to determine potential reuse or disposal, any surface disturbance, and all buried infrastructure.
Then any potentially contaminated soil was preferentially treated onsite and compacted land areas were de-compacted before being covered with at least 20 centimetres of returned topsoil.
Finally, seeds and tube stock plants were introduced with weeds monitored and managed until grasses made up at least 70 per cent of the land coverage.
The Carmichael Rail Network was constructed by Bravus Mining and Resources, formerly known as Adani Mining, as part of the Carmichael mine and rail project, before they handed the rail to us at Bowen Rail Company for the operations and maintenance.
During construction, the project team made sure all vehicles that came onto the site were cleaned at an approved weed wash down station and certified before they were allowed onsite. Any vegetation was certified weed-free by the supplier through the Queensland Government's weed hygiene declaration.
Today we continue to work to manage and improve the local ecosystems found across our operation by conducting weekly monitoring along the corridor to check for rubbish and debris, any environmental nuisance, and amenity issues.
Air and water checks are also performed and potential coal dust and any impacts from weather assessed. This monitoring is done across the site at both ground level and using drones to capture larger areas.
Weed management is conducted to improve the land, targeting the noxious pests parthenium, prickly pear, harrisia cactus, velvety tree pear and the rubber vine.
We continue to conduct regular inspections for weeds, especially at key water courses.
Protecting topsoil for a better environment
Bowen Rail Company Environmental Supervisor Hadley Goodin knows the value of topsoil when it comes to land restoration.
“It’s environmental gold when it comes to rehabilitation,” he said.
"That's why in the civil stage of constructing the Carmichael Rail Network we reclaimed the topsoil and stored it for future use.
"The good news is we've been really successful with that to date."
"That comes with its own set of management requirements and challenges as you have to stockpile it in long strips and you can't heap it too high otherwise it starts to break down internally and degrade.
"The idea is to preserve the topsoil microbial activity and also the seed so it can regerminate when it's back on site.
Planning for a future alternative land use
If the day comes when the Carmichael Rail Network is no longer in use, the corridor will be transformed into a landscape that can be used for another activity such as grazing. This would be achieved in a way that complies with the laws and regulations of the time.
In the short-term after closure, this may include the progressive reshaping and stabilising of the corridor and managing soil and reuse.
Over time, the aim would be to re-establish functionally important and structurally dominant native species in the area, and shape the land so it is consistent with the surrounding water-flow and landscape processes.
Monitoring systems for erosion, surface water, geotechnical stability, ecology, and dust would be in place to ensure effective rehabilitation for five years.
Final rehabilitation will only be deemed to be complete when the diversity of shrubs and trees, and the proportion of grass cover and weeds, is comparable to surrounding sites.