​Accelerating Consolidation of Mine Tailings using Electro-osmosis Dewatering Technology​

The Challenge

All mining operations involve the production of waste. Many regard such waste (tailings) and their environmentally acceptable storage as constituting the largest waste problem on Earth because of the enormous damage and loss of life that have resulted from failures of tailings storage facilities (Draves & Fox, 1998; Hudson-Edwards et al., 2003). This project focuses on a dewatering technology, electro-osmosis (EO), which has yet to be fully operationalised, for improving the strength, stability, and settlement characteristics of the tailings. This technique involves the application of a potential difference between electrodes that causes water flow to the negatively charged cathodes. Although this method has been successfully used in traditional civil engineering applications (such as increasing pile capacity, stabilization of excavations, slopes, and embankments, and increasing the strength of clays), to the author’s knowledge, its potential application for the consolidation of mine tailings is yet to be fully investigated.

Proposed Solution

The main objective of this research project is to investigate the effectiveness of utilizing electro-osmosis dewatering technology to accelerate the consolidation of mine tailings. The shear strength behaviour and volume change of tailings slurry with respect to the changes in the water content will be investigated to analyse the strength, stability, and settlement characteristics of the tailings. The aforementioned objectives will be achieved via the evaluation of two main hypotheses:

• electro-osmosis dewatering technology is an effective approach to accelerate the consolidation of mine tailings, and
• electro-osmosis dewatering increases undrained shear strength of the tailings, and subsequently enhances the stability and accelerates settlement.

The findings of this research study can be used to implement electro-osmosis dewatering technology at larger scales in the mining industry by addressing the lack of developed methods and procedures.

Proposed Benefits to WA

Currently, there are more than 300 active tailings storage facilities (TSFs) in WA. Since the failure of one of these TSFs could cause significant damage to the surrounding properties, local environment, and people’s lives, prevention of such incidents is of paramount importance. Electro-osmosis dewatering technique is a potential method to accelerate consolidation of weak, highly compressible tailings materials. Adopting this technique can minimize the associated risks by improving stability and diminishing the footprint.

Furthermore, a significant number of mines in WA are approaching the closure phase. High water content with poor undrained shear strength could restrict the TSF closure. Electro-osmosis dewatering can be utilized to enhance the strength of the tailings and subsequently enable closure and reclamation.

The findings of this research can be used to implement electro-osmosis technology at larger scales in the WA mining industry by addressing the lack of developed methods and procedures.

Project Duration

3 years and 6 months. Scholarship awarded 2023.