UQ develops mining waste solution

Development of a mineral gel technology that will provide effective, low cost, rapid management of toxic red mud from alumina refineries has received a major financial boost.

Red mud is the waste product generated by the production of aluminum oxide, or alumina.

University of Queensland Sustainable Minerals Institute researcher Dr Tuan Nguyen has secured almost $500,000 to develop the gel technology that will transform the way refineries manage waste sustainably and economically.

Dr Nguyen said the gel had the potential to minimise pollution risks from red mud storage.

“New and cost-effective technologies are urgently required to assist the refinery industry to operate with much improved environmental outcomes,” he said.

“Safely storing and processing red mud is difficult, costly and time-consuming.

“But the gel chemically links mineral grains into stable and benign soil-like structures so it can sustain plant root systems, resulting in a successful rehabilitation outcome.

“This will help massively with seepage management and red mud rehabilitation.”

Dr Nguyen won a $180,000 Advance Queensland Industry Research Fellowship last week.

Rio Tinto and Queensland Alumina Limited have topped that up to almost $500,000, contributing cash and in-kind support.

“This funding is an outcome of strong collaboration between research and the environment teams of industry partners Rio Tinto and Queensland Alumina Limited, which produce $6 billion of alumina a year,” Dr Nguyen said.

“They accumulate millions of tons of red mud which is stored across 1500 hectares of dams in Central Queensland.”

Dr Nguyen recently joined the Sustainable Minerals Institute to work on research to develop cost-effective and sustainable technologies for rehabilitating red mud dams in Queensland and the Northern Territory.

Research group leader Associate Professor Longbin Huang said the technology was an important part of a new research theme of ecological engineering of mine wastes.

“Tuan’s appointment and the jump-start of this excellent funding opportunity are likely to lead to significant advancement of new technology to rehabilitate toxic red mud,” he said.

“This technology will help establish a red mud rehabilitation industry in Queensland, and make The University of Queensland the leading hub of red mud research and applications.”

Mining waste recommendation from NT EPA

The Northern Territory Environment Protection Authority (NT EPA) has assessed a proposal north of Alice Springs to mine rare earth elements, with naturally occurring radioactive materials to be permanently stored onsite.

The NT EPA concluded the Arafura Resources Ltd’s Nolans Project could be managed to avoid unacceptable environmental impacts and risks.

Its key recommendations focus on ensuring best practice management of tailings, residue and waste during operation, closure and post decommissioning.

The agency noted potential contaminants and the presence of naturally occurring radioactive materials in waste streams warrant independent technical review and operational oversight to ensure the risks are minimised to the lowest extent practicable and to promote a transparent regulatory process.

The proposal is to mine rare earth elements, key components in many green and sustainable products, such as wind turbines for the clean energy industry and hybrid vehicles. The proposal includes open cut mining and processing over a 55 year mine life.

The proposal also includes groundwater abstraction from a new borefield and permanent diversion of an ephemeral creek.

The proposed site is 135 km north-northwest of Alice Springs and 10 kilometres west of Aileron roadhouse and Alyuen community.

NT EPA Chairman, Dr Paul Vogel, said the NT EPA identified potentially significant environmental impacts and risks associated with the proposal and made 16 recommendations to avoid and mitigate those impacts.

“This proposal comes with long term environmental risks that will require a high level of ongoing regulatory scrutiny across government,” Dr Vogel said.

The NT EPA considers there is potential for impacts on groundwater hydrological processes and associated environmental values.

The sustainable use and management of groundwater resources is important in an arid zone where the project is located.

The NT EPA recommends further hydrological investigations including refining the groundwater model, setting site-specific groundwater level triggers and adaptive management of groundwater use.

To ensure best practice closure and rehabilitation, the NT EPA considers the project should effectively integrate mine closure planning with mine operational planning and that progressive rehabilitation is undertaken during its operations.

The NT EPA has recommended that the security bond be revised based on the updated Mine Closure Plan to ensure the costs of rehabilitation and post-closure liabilities are not borne by the Northern Territory Government and the community in the event of the operator abandoning the site or becoming insolvent.

It notes that uncertainty remains around the potential for significant environmental impacts over the life of the project.

The NT EPA emphasises that the environmental commitments, safeguards and recommendations outlined in the Environmental Impact Statement, the Assessment Report and in the final management plans must be implemented by the proponent, with a high level of oversight and strong compliance enforcement by the relevant regulator throughout the life of the project to deliver acceptable environmental outcomes.

The NT EPA has provided its assessment report to the Minister for Environment and Natural Resources, Lauren Moss, for consideration.