Mine renewal possibilities if we dig deep

The closure of a mine is usually seen as a disaster — there go the jobs, the revenue, and the people giving life to a regional community, but with mine renewal opportunities, it doesn’t have to be so.

Academics, industry and governments are beginning to see mine closures as opportunities.

They represent a wealth of established infrastructure.

There are heavy-duty roads, electric power generators and networks. There are buildings and accommodation, communications facilities, store rooms and septic tanks.

Repurposing these is far more cost-effective than starting from scratch.

“Everybody is focused on energy transition at the moment and the need to decarbonise. There are some really novel projects happening, looking at old mine pits and turning them into pumped hydropower sites,” says Dr Guy Boggs, CEO of the Transformations in Mining Economics (TiME) Cooperative Research Council (CRC) who points to the old Kidston gold mine west of Townsville as an example.

It’s about to begin a new life as a battery.

A solar energy farm is on the site and the electricity is being used to power pumps filling an old raised mining pit.

“The mines have strong electricity grids, so you can make use of the infrastructure that was built during the mine,” he says.

The Kidston Pumped Storage project is projected to produce 250 megawatts of electricity. That’s enough to power 143,000 homes.

But the benefits go far beyond producing power on a cloudy day.

Mine renewal regional revival

Regional Australia’s experiencing another mining boom. There’s soaring demand for supplies of the rare earths and critical minerals needed for the batteries and turbines of the new renewable energy economy. But as Cosmos has reported before, a number of times, tumultuous international politics has also emphasised the need for diversity – and reliability – of supply.

At the same time, Australian mine closures are expected to spike. This is because many existing sites are approaching the end of their viable lives.

Generally, a mine will remain operational for between 10 and 30 years. The most recent resource boom began about 30 years ago.

When they close, most attention is focused on land rehabilitation, water management, soil replacement, groundcover monitoring, vegetation management, post-mining land use and removal of infrastructure.

And this remediation work is necessary.

“There are major technical and economic challenges in rehabilitating large-scale mines which have significantly modified the natural landscape,” reports the University of Queensland’s Sustainable Minerals Institute. https://stories.uq.edu.au/smi/2022/csrm-mine-closure-hub/mine-closure-overview/index.html

There’s also the long-term population and economic impact that can echo through regional communities for decades to come.

But, as the institute points out, many mines already have extensive solar or wind power generation. These don’t need to be torn down. Instead, they could supplement local community supplies or drive a new industrial hub.

“A well-managed mine closure process can establish the basis for a sustainable post-mining future and create new opportunities, including for alternative industries and businesses, stronger livelihood and food security, acquisition of new labour skills, and reuse of mining infrastructure,” the institute says.

Opportunity knocks

Pumped hydro is just one option. Researchers are also exploring the possibility of turning new lakes over old mining pits into geothermal generators (where the heat exchange between water and soil is exploited). Others are looking at using mine shafts as gravity batteries (where heavy weights are hoisted at times of excess renewable energy generation and let loose to drive generators when there’s a deficit).

Other old mines are finding new use in unexpected ways.

Stawell Gold Mine, for example, is the site of an underground “dark matter” physics lab.

Sustainability designer at Business for Development, Meg Kauthen says repurposed mine infrastructure can help reduce the boom-bust impact mines can have on regional areas.

“If we get infrastructure aligned to the community’s needs, it’s a fantastic investment beyond the life of the mine,” she says, pointing to an example in Africa where one facility was repurposed to support the local clothes manufacturing industry.

“We suggest that Australian mines and mining communities need to approach the development of infrastructure in the same way.”

Federal, state and local governments also have a role to play in turning potential into reality.

“By diversifying the economic opportunities in regional Australia, it is hoped that more people will migrate from the capital cities to help grow smaller communities,” she adds.

Dr Boggs and Ms Kauthen will be among the environmental, economic and social-science experts addressing the International Mining and Resource Conference (IMARC) in Sydney between November 2 and 4.