Scale up leaching tests for spoil salinity predictions

Speaker: Associate Professor Mansour Edraki

 

Abstract: The release of salts from spoil piles can potentially affect surface and groundwater quality and the quality of water in final voids. Current hydrogeochemical salt balance models often assume that the total amount of inherent salts in spoils will be released over time or predict that water salinity will increase into the future based on site monitoring data from electrical conductivity measurements. The closure and rehabilitation of spoil piles and final voids based on such model outputs is uncertain and may be overly conservative, expensive and uncertain.

The overall aim of this two-stage ACARP project was to develop a process for estimating long-term salinity generation rates from different classes of mine spoil. With support from ACARP and in-kind contributions from The University of Queensland, a mesoscale (1-1.5 tonnes) spoil leaching test facility was set up at UQ’s property in Pinjarra Hills to bridge the gap between small scale laboratory tests and field monitoring of spoil piles. A simple numerical model that is accurate across two scales (column and mesocosm) was developed to investigate scaling of the kinetic parameters for fast leaching processes, and slow leaching processes.

Mansour will share the findings of this project followed by a Q&A and online discussion.

 

Bio: Mansour is a Principal Research Fellow and Group Leader - Environmental Geochemistry at SMI's Centre for Mined Land Rehabilitation. His research interest is in understanding and predicting the source, transformations and fate of contaminants, particularly acid and metalliferous drainage (AMD), in the mining environment. Through field monitoring, laboratory experiments and modelling he follows the geochemical pathways of heavy metals, metalloids (e.g. arsenic) and salts and investigates the natural processes that may degrade the quality of surface and groundwater and natural soils. Mansour uses that knowledge to quantify the extent of the current and future effects of those processes for optimum remediation and rehabilitation outcomes. Read more