Metal mobility

At the EGEL, we study the roles that minerals play in metal and metalloid mobility and the stability of trapping hazardous metals in minerals. This has particular relevance to mine site remediation and enhanced weathering for carbon mineralisation.

Mine sites and ore processing circuits are particularly interesting places to study mineral dissolution and precipitation reactions. Exposing rocks to Earth’s surface conditions initiates a suite of chemical reactions and mineral transformations. With the added ingredients of water and air, unstable minerals break down and new minerals form from the elements released, often also incorporating water and gasses from the environment. Because mine sites are commonly rich in a variety of metals, the resulting anthropogenic mineral assemblages are always unique and sometimes bizzare.

The mobility of toxic metals during these reactions can sometimes cause contamination of waterways and soil. Managing metal mobility during remediation efforts and industrial processes costs industry and government many millions of dollars every year in Australia alone.

We are working on a number of projects that address metal mobility with the support of the Australian Research Council, industry partners, Carbon Management Canada and state government. Some of these are described below.

Remediating arsenic contamination. Arsenic contamination is a serious environmental problem for many current and abandoned mine sites across Australia and the world. The strategies commonly used to mitigate release of other common metals at mine sites (i.e. Cu, Co, Zn, Pb) are often ineffective in trapping and removing this redox-sensitive metalloid. We are working with our colleague, Dr Simon Jowitt, to investigate As-bearing mineral phases at abandoned mine sites in Australia to (1) assess their stability as novel traps for this element and (2) address the potential for As release under proposed remediation treatments.

Metal mobility during enhanced weathering and carbonation. Carbon mineralisation technologies commonly use acids to enhance the rate of silicate mineral dissolution and carbonate precipitation. However, the favoured feedstock materials for carbon mineralisation, such as mine tailings or alkaline industrial wastes, commonly contain low levels of potentially hazardous metals. Therefore, the use of acids to accelerate mineral dissolution poses a potential risk for metal release into the biosphere. We are investigating the mobility of common trace metals found in ultramafic rocks and assessing the capacity of alteration products to aid in their sequestration.

Trapping non-target metals during Cu-U ore processing. Our research group is involved in the ARC Research Hub for Australian Copper-Uranium, which is led by The University of Adelaide. The Monash-based node is led by Prof Joël Brugger and we are currently seeking creative and motivated Ph.D. students to join this project. We are investigating the behaviour of Cu-U ore and gangue minerals to improve extraction of non-target metals during ore processing. The end goal is to improve the environmental sustainability, marketability, and efficiency of Cu-U ore processing.