Mining land returns to farming on the Darling Downs
A FORMER coal pit on fertile Darling Downs soil has been born again, now producing nutrient-rich pasture to grow out hundreds of cattle.
Mining company New Hope Group is in the middle of a five-year scientific trial at its mine just west of Toowoomba to find out whether land that was once carved up for coal could be rehabilitated and used again for grazing and cropping.
The results have surprised even some of the research team.
It is not a new idea, grazing trials on previously mined land have been happening since the 1980s but the level of scientific scrutiny on this project is unprecedented.
The trial results showed that, on average, performance from cattle grazing the rehabilitated pastures was equal to or better than the performance of the control, or unmined, paddocks.
Agricultural consultants Outcross Agri Services have overseen the trial that consultant Tom Newsome said was different from the usual mining industry approach.
"Traditionally the mining industry focuses on an environmental outcome and not a commercial outcome as well," Mr Newsome said.
"This project focused on rehabilitating the land so it can be used for viable and sustainable cattle production into the future."
New Hope Group set up Acland Pastoral Company to run its agricultural operations.
Manager Ben Muirhead is an experienced cattleman who has worked across Australia.
But his high-visibility orange shirt hints that his employer is not like the average cattle tycoon.
"Cattle grazing on rehab country has gone on forever and a day, it's just that no one has gone through and recorded it," Mr Muirhead said.
He said he was under pressure to "make it work" from an economic perspective.
And he said the project was "getting close" to making money.
To rehabilitate the land, topsoil that had been scraped off and stockpiled before mining began was spread across the surface to a depth of 30cm.
University of Southern Queensland soil scientist John Bennett said they had so far found similar pasture rooting depths in the unmined soils and the rehabilitated soils.
"This suggests the inter-burden (mine spoil) is capable of supporting the pasture," he said.
However, Dr Bennett admitted that with soil creation taking literally millions of years, they would never know 100% whether the system would be completely sustainable.
"But we haven't seen anything negative so far to suggest the pastures won't be sustainable in five years," he said.
A big con?
THE founder of anti-mining group Lock the Gate Alliance has described the rehabilitation of mining land as "one of the industry's biggest cons".
"There isn't any rehabilitated land anywhere in Australia which has been returned to anything like the condition it was before mining," Drew Hutton said.
New Hope Group does not have data showing the quality of the land before it was mined.
Its oldest rehabilitated land is 12 years old, so it instead uses "control" parcels of land that have similar soil structure and topography to the trial paddocks.
And while the mining company funds the trial, University of Southern Queensland researcher John Bennett dismissed any claims that would influence its outcome.
"We would not be involved in something that would compromise our independence as a university," Dr Bennett said.
"We wouldn't be involved if we didn't have freedom of speech."
Mr Hutton said it was not possible to rehabilitate the land to its previous soil profile "without spending enormous amounts of money and using enormous amounts of skill".
"I don't believe for one moment that what is happening at Acland is anything more than a PR (public relations) exercise to hoodwink the people and the government that this is possible."
It is expected the State Government will make a decision in coming weeks as to whether the mine's planned Stage Three expansion will go ahead.
Grazing on coal
- Acland Pastoral Company runs 1400 head of cattle, down from about double that because of dry conditions
- Average cattle turnoff weight is 450-470kg
- 5% of the 24-hour mine's machinery is devoted to rehabilitation
- The oldest rehabilitation block is 12 years old
- Mungbeans and sorghum are growing on former mining land, irrigated under a centre pivot sprinkler
- The site's water is completely sourced from rainfall plus treated water from Toowoomba's Wetalla Water Treatment Plant
- Water is only extracted from underground for domestic use at the office facilities
- 97% of the coal from Acland is bound for export with 3% for domestic use
- The coal pit is 175ha
- The operation employs 280 local workers and 160 contractors, none of whom is fly-in fly-out