Feasibility of effective metal recovery from tailings material via electrokinetic in-situ leaching

The Challenge

The large number of tailings storage facilities (TSF) poses a large environmental and an economic liability for the mineral industry. For example, several tailings disasters have occurred worldwide due to the poor management of TSFs. On the other hand, TSFs can store significant amounts of metals, many of which are under strong demand due to a strong push globally for a decarbonised economy.

Proposed Solution

This PhD project will provide an initial proof-of-concept for the feasibility to recover specific metals from mine tailings material through electrokinetic in situ leaching (EK-ISL). The main hypothesis is that the application of an electric current via electrodes emplaced within the tailings material induces an electromigration process that can transport lixiviants and metals at sufficiently high rates to effectively extract valuable metals hosted within the waste material. The PhD project will focus on laboratory-scale investigations for a range of promising tailings material / lixiviant combinations and thereby specifically investigate and optimise the effectiveness of lixiviants under EK conditions.

Proposed Benefits to WA

Western Australia is home to a large number of tailings dams that host various valuable metals such as nickel and gold. Successful in situ extraction of those metals would be of direct economic and environmental benefit for Western Australia. Furthermore, Western Australia will benefit through the development of critical IP that can be applied globally.

Using an EK-based approach to mineral extraction holds the promise of an added benefit of improving the geotechnical stability of these facilities. Aside from EK enabling mineral extraction, the electro-osmotic effect drives water to the cathode; pumping this water from a suitably designed cathode well will enable reduction in the moisture content and hence improve the strength of the tailings. Improvements in the stability of legacy dams through this process reduces long-term liability that might otherwise fall to the state to fund repairs for.

Supervisors

Professor Henning Prommer, Professor Andy Fourie, Dr James Jamieson