Technology and respect for ancient knowledge are combining to repair the ecological and personal scars carved over decades by the vast Ranger uranium mine.

Surrounded by Kakadu National Park, the 79 sq km site, pocked by deep holes and abandoned mining ponds, lies some 260 km southeast of Darwin near the town of Jabiru, on the land of the Mirarr people.

“It’s really sad for us,” senior traditional owner Yvonne Margarula says.

But a new way of healing country is underway as the mine’s former operators work with Gundjeihmi Aboriginal Corporation and the Northern Land Council to draw on their wisdom.

“It’s very important for me and my people,” she says.

Failure is not an option for owner Rio Tinto after it detonated Western Australia’s 46,000-year-old Juukan Gorge rock shelters two years ago, devastating traditional owners and shocking many Australians.

But taxpayers could be on the hook to fund some of the work at Ranger as timelines and costs blow out.

The open cut mine, run by Energy Resources Australia, began producing uranium oxide via acid leach extraction in 1981.

Operations ceased more than 30 years later and processing of stockpiled ore ended last year, meeting the terms of access rights.

The oxide continues to be sold on the world market, partly funding rehabilitation.

View from Gunlom, Kakadu National Park, May 7, 2009. (AAP Image/Susanna Dunkerley)

Ranger’s pit one alone, where backfilling began more than 25 years ago, was once 170 metres deep. Tree planting has begun on what is now a large and flat surface area of almost 40 hectares.

Owner-operator of Kakadu Native Plants Peter Christophersen and his team have collected seeds and propagated plants, and are seeing parts of the site go from dust and rock to living brown and green.

Grasses like eriacne and lemongrass have been reintroduced.

There are fruiting quinine bushes while stringybark, woolybutt, billygoat plum and wild peach will cast shade.

“When we talk about birds and animals, I think if you put manme (food) there, they will come,” Gundjeihmi Aboriginal Corporation member Djaykuk Djandjomerr says.

“People used to come down from the rock country to the water because there was more food – it was especially good in the mid-dry season when there were magpie geese.”

He says the fathers of the current Mirarr generation and their sisters understood the place.

“They lived a very good life here.”

The people Mr Djandjomerr speaks of collected water chestnuts, went fishing and hunting, and camped around the edges of the billabongs before being forced to move into Jabiru.

Their former swimming hole is now an abandoned retention pond that was used to manage toxic runoff.

Ranger Uranium Mine in the NT

Uranium oxide from the mine has powered the world’s nuclear power plants, under the Atomic Energy Act that gave ownership of the resource to the Commonwealth.

Ms Margarula, whose father was in the 1980 mining protest documentary Dirt Cheap, cried at the first tree-planting at pit one last year.

“My dad’s footprints walk around here.”

She says the mining company and others pushed hard and Ranger could not be stopped.

“He tried.

“I’m here, the daughter one, now.”

Charles Darwin University researcher Rohan Fisher has developed 3D-landscape modelling with Mirarr knowledge so company executives understand the extent of what must be done.

After decades of manipulating satellite remote sensing data and geographic information systems for bushfire management, he’s applying those skills to map the disconnection caused by the mine and phases of repair.

Layers of projections can capture the current state and compare it to how it is going to look.

“We can then project over that, sophisticated water-flow modelling,” Mr Fisher says.

“This is important to show where you might get sediment run-off from the mine site into important billabongs and wetlands that they will continue to use.”

Brad Welsh.

The hydrological modelling has been animated, based on rainfall events.

Mr Fisher says the tactile tool communicates with the most important stakeholders, the Mirarr, and has been powerful in mining boardrooms too.

“People have been dispossessed of that country for 40 or 50 years, so there are a lot of cultural sites through the Ranger lease but only a few people have memories of walking that country,” he says.

Some of the rehabilitation, when filling in the old pits, involves careful consideration of where to put rock piles or shelters as habitat for returning species and how they will interact with water flows.

A cultural database is being developed with footage of some of the older people’s stories, as an interactive platform with the 3D model.

Mr Fisher’s involvement came through the land council that works with the corporation representing the Mirarr.

ERA has joined in, saying it needs the tool – on site and at board meetings in Darwin.

“It opened up clear communication between the people who were doing the rehabilitation and some of the senior executives who knew about it as an abstract concept that they had to fund,” Mr Fisher says.

Rio Tinto agrees the technology is vital to Ranger’s rehabilitation.

“This is particularly true of water treatment and the backfill and capping of the former open pits,” a spokesman says.

“Their application at Ranger is definitely leading edge.”

He says the 3D modelling is a powerful way to demonstrate the process, especially the landforming and revegetation.

The largest uranium deposit in the southern hemisphere was discovered in 1969 when an aerial survey detected a radiation spike around Djidbidjidbi, known as Mount Brockman.

The restoration team has used nearby reference sites in Kakadu National Park, which has world heritage listing as a natural and cultural treasure, aiming to return the landscape to similar conditions.

However Rio Tinto wants more time to complete the single largest rehabilitation exercise in the history of Australian mining.

Failure to meet a 2026 deadline will demand new laws and more capital.

ERA boss Brad Welsh says he expects federal parliament to approve two more years, meaning a revised cost up to $2.2 billion – more than twice earlier estimates.

  • Story by Marion Rae, AAP