:: P906 Emerging Technologies for Ecological Rehabilitation at Mine Closure

An AMIRA International collaborative project proposed by research institutions in Australia, South Africa and Chile seeks to assist copper producers in identifying and applying new low-cost and environmentally-friendly approaches to mine decontamination, remediation and restoration through the use of a unique species of plants.

The project will promote environmentally sustainable methods for the closure and rehabilitation of mine sites, which is considered a significant challenge for most mining operations around the world.

Project P906, Emerging Technologies for Ecological Rehabilitation at Mine Closure, will investigate the benefits of Phytoremediation, defined as the use of a naturally occurring plant species called 'metallophytes', which thrive on metal-rich substrates. Metallophytes either remove metals from contaminated substrates or render them into environmentally innocuous forms.

The proposed project is a joint venture between the Chilean Research Centre for Mining and Metallurgy (CIMM), the School of Botany at the University of Melbourne, and the University of Kwazulu-Natal in South Africa. AMIRA International will facilitate the project.

Three types of phytoremediation are appropriate for the rehabilitation of mined sites:-

• Phytoextraction, which uses metallophytes called hyperaccumulators, to clean-up metals from polluted soils
• Phytostabilization, which uses metallophytes to immobilize metals in soils or a metal-rich mine waste and
• Rhizofiltration, which uses metallophytes to extract metals from water and industrial waste waters.

Joe Cucuzza, Business Unit Leader for Resource Transformation at AMIRA International, describes the project as an opportunity for industry to enhance its green credentials as well as developing 'natural' cost-effective solutions to the challenge of rehabilitation. "This project will aim to identify green technologies for the rehabilitation of mine sites, but also promises the possibility of identifying environmentally friendly approaches to mining," he said.

"The proposal addresses important areas of R&D related to Mine closure as identified by the Copper Technology Roadmap recently developed by AMIRA with the support of the world's major copper producers," said Mr Cucuzza.

At the University of Melbourne, Professor Alan Baker is coordinating the School of Botany's involvement. Prof Baker was involved in the Mining, Minerals and Sustainable Development (MMSD) project of the Global Mining Initiative both in Australia and worldwide, and his research career has centred on the interactions of plants with soils and sediments contaminated with heavy metals.

"The proposed AMIRA project will build on the Group's knowledge base in a co-ordinated research program in Australia, Latin America and South Africa. It will provide the minerals industry with new materials and techniques for the ecological restoration of copper-contaminated soils in semi-arid (Mediterranean) climates," said Prof Baker.

Phytoremediation has shown to be both effective and cost beneficial when compared to traditional technologies. It is environmentally-friendly as it can be applied in situ to large areas and does not alter the biological, chemical, and physical properties of the substrate, thus allowing for alternative land uses and/or ecological restoration of the site.

The proposed project has the following key objectives:-

• To undertake a geobotanical inventory of metallophytes in Latin America, South Africa, and Australia
• To establish the optimal use of local metallophytes in ecological restoration through environmental technologies (e.g. phytoremediation) associated with mining
• To establish which of the identified metallophytes could be potentially applied to bio-mining
• To transfer the necessary knowledge and know-how to sponsors that will permit exploitation of the key project outcomes in their operations

Sponsors of this project will receive the following strategic benefits:-

• An opportunity to further demonstrate their willingness to seek sustainable solutions to solve the problem of mine site rehabilitation and prior to and after mine closure
• An opportunity to demonstrate active stewardship of rare plants that exist in and near mine sites by undertaking a scientific inventory and conservation
• Identify both commercial and non-commercial uses of metallophytes
• Development of 'green' technologies that could be applied to mine site decontamination, remediation and restoration
• Enhancing the development of a world-class research infrastructure that will provide the necessary critical mass to undertake research on metallophytes

More specifically, sponsors of project P906 will be receive the following direct benefits:-

• A priority geobotanical survey at a mine site of their choice in each of the countries that will be part of the project. This will depend on the final scope of the project which will be decided in consultation with sponsors
• Identification of metallophytes that could be applied to mine site rehabilitation
• Demonstration of the usability of candidate species for rehabilitation (phytostabilization in this first stage and phytoextraction and phytomining in further projects)
• Identification of target species that may be suitable for phytoextraction and bio-mining. Actual demonstration of suitability is not part of this project

Exploiting nature's own solutions towards natural sources of anomalous metal accumulation not only offers an elegant solution to the problem, but offers a solution that is both sustainable and potentially more acceptable to society.