Mine rehabilitation: making progress with biodiversity

By Chelsea Wallis
May 5, 2013 – Mining IQ

Flowers in the Blue Mountains, NSW (Photo: Chelsea Wallis)

Flowers in the Blue Mountains, NSW
(Photo: Chelsea Wallis)

One of the greatest assets in breaking down mining stereotypes is the pioneers in progressive mine rehabilitation. Environmentally friendly processes and increasingly diverse ecosystems are becoming standard as companies consider local ecosystem rehabilitation as a part of the on-going mining process.

We caught up with Idemitsu Australia Resources Corporate Sustainability and Environment Manager Dr. Jan Green and Parsons Brinckerhoff Team Manager, Alex Cockerill, to better understand these progressive rehab techniques.

“There’s an increasing focus on establishing complex and diverse natural ecosystems as part of mine rehabilitation,” she says. “With progressive rehab, it takes a much shorter time after the mine closes before the original flora and fauna can take over naturally.”

Her current project is a 6- to 7-year-old mine that will eventually return to a box gum woodland with white box gum trees. One of the biggest challenges, she explains, is keeping up with the mining as it happens.

Clearing is strictly scheduled between summer and autumn to allow bird species, for example, to nest in the winter and raise young in the spring. Cockerill says the team salvages hollow logs and timber for the provision of supplementary fauna habitats within the rehabilitation, and collects the seeds of local species of plant from the adjoining forest for propagation in a nursery.

Using local species gives them a greater chance of growing because the topsoil is recreated with greater accuracy. In turn, local fauna, from invertebrates to birds and mammals, are attracted to familiar landscapes.

“With the progressive establishment of increasingly complex vegetation structure and diversity these ecosystems encourage more local species back onto the mine site,” Cockerill explains.

“It’s then supported by biodiversity monitoring to target measurable performance criteria throughout the life of the mine and rehab,” Dr. Green says.

There’s good reason that Dr. Green believes progressive rehab should be the norm.

“We are mining in a state forest and to rehabilitate progressively is part of the approval conditions,” she admits, “But progressive rehab is better in terms of the environment and community acceptance.”

Abandoned mines and plateaued soil heaps are not natural and can take longer for regeneration because of erosion. But progressively rehabilitated mines have extra resistance to erosion as spoil piles are benched with draining slopes and layered with mulch.

“Importantly, progressive rehabilitation limits the time the ecologically valuable topsoils are stockpiled”, Cockerill says. “Reusing these topsoils progressively will maximise the survival of soil biota and the potential natural regeneration from the forests, soil and seed bank.”

But the biggest challenge may be communication. It is difficult to fight misinformation, especially when it comes to mining and the environment explains Dr. Green. “The most important thing you can do is to engage with the local community, the regulators and interested groups to design and deliver a landscape that everyone has had the opportunity to discuss,” she says.

For more info
In addition to her role at Idemitsu, Dr. Green is an adjunct lecturer at Sunshine Coast University on sustainability and integrated environmental management.

Want to hear more from Dr. Green? See her in person in Brisbane, Australia at the Mine Rehabilitation and Closure Conference 25-27 June 2013.

Return to print archives…