Sydney academics urge global action to reduce pollution

Professor Elaine Baker, a geoscience expert from the University of Sydney’s School of Geosciences and UN Environment collaborating centre GRID-Arendal, is among a group of academics, business leaders and civil society leaders who recently gathered in Nairobi, Kenya, for the third UN Environment Assembly (UNEA 3), pushing for a pollution-free planet.

On the sidelines of the UN Environment Assembly, Professor Baker presented her new report, Mining Tailings Storage: Safety is No Accident, which examines several recent mining waste disasters.

“Companies need to change the way they assess risk and – as Guyanese President David Granger said during his keynote address – we must put people before profit,” she said.

“All parties at the extractive industries event at UNEA 3 agreed that UN Environment should play a key role in facilitating further discussions, in line with the recommendations in our report.

“I hope in the next phase we will be looking carefully at the establishment of some sort of compulsory insurance scheme to protect people and the environment from extractive pollution.”

Report examines safety, management and impacts of mine tailings

The Mining Tailings Storage report is part of the United Nations Environment Programme’s Rapid Response Assessment series, which is reserved for the most pressing environmental problems. The report examines why tailings dams fail and makes recommendations to fix the problem.

The report points out that mine storage dams fail every year, destroy entire communities, and livelihoods and massively damage the environment.

“The technical capacity and knowledge required to manage mine waste exists – it just needs to be implemented,” said Professor Baker, who co-authored the report.

The report acknowledges the recent strides taken by mining companies, industry bodies and regulators to prevent catastrophic incidents, but states that existing engineering and technical know-how to build and maintain safe tailings storage facilities is still insufficient to meet the target of zero catastrophic incidents.

According to the report, a zero-tolerance standard would be possible to implement but would require a longer-term approach, with dedicated personnel and funding.

Professor Baker said Australia is in a position to be a leader in developing the governance framework required to achieve zero tailings dam failures by implementing the recommendations and actions outlined in the report.

Harnessing waste for constructive purposes

University of Sydney chemical engineer Associate Professor Marjorie Valix is an expert in mineral processing and mine waste with a special interest in re-evaluating the traditional production cycle towards waste minimisation, reuse, recycling and other recovery. Associate Professor Valix contributed to the report by investigating ways to capture and generate value and minimise the ecological impact of mine tailings.

“To provide context to the scale of the issue, an average sized copper mine processes up to 270,000 tonnes of tailings a day, but only 1750 tonnes of copper is recovered and the rest ends up as waste,” she said.

“For this report, I investigated how this waste could be used in other ways – from construction materials like bricks or cement, to materials for capturing emissions and CO2 from the atmosphere.”

In the report, Associate Professor Valix also stressed the need for alternative technologies such as bioleaching methods to enable re-mining and recovery of valuable metals from mine tailings.

“Tailings can be transported through soil, water and air and once they are no longer confined in the mine site they can be taken up by plants and grazing animals,” she said.

“For this report I elaborated on the current novel technologies for managing the ecological impact of tailings. The methods included using secondary minerals that fills up the pores of tailings dam and acts as cement (referred to as hardpan formation) that prevents the flow of water and stabilises the dam with methods that use plants to suck up the metal contaminants from the soil.”

Associate Professor Valix also highlighted the powerful way that inexpensive wireless sensors can be used to manage tailings dams.

“These sensors could be used to monitor local conditions in tailing dams every few seconds if required and could provide early warning of structural failure to leaks and release of acidity and heavy metals,” she said.

“We hope this report will encourage targeted action at the policy and technical level to ensure holistic changes are made to the way tailings are stored and managed.”

The University of Sydney, GRID-Arendal, and other international partners, plan to host a policy forum in 2018 to discuss the development of an international convention on mine waste.