SMI researchers ready to test new technique for predicting spoil salinity in mine waste

11 August 2021
Associate Professor Mansour Edraki

Sustainable Minerals Institute (SMI) researchers are searching for partners in the Queensland coal industry to help them trial a new technique for predicting the rate at which mine waste releases salt into the environment.  

Following a two-stage project supported by ACARP, SMI’s Environmental Geochemistry Group are confident that new procedures and models to predict the rate at which salinity is generated and released from coal spoils will offer industry new insights into an often-neglected area of closure-planning.

Spoils are waste rocks produced by open-cut coal mining operations which consists of rock formations and soil cover overlying or interbedded with coal seams. They typically feature a high density of salt which is environmentally damaging if released in high concentrations.

Environmental Geochemistry Group Leader Associate Professor Mansour Edraki said the new modelling would ensure mining companies have a better understanding of their spoils.

“Dissolution of salts in rainfall and their subsequent transport into waterways can adversely affect water quality, potentially for decades following the cessation of mining,” Associate Professor Edraki said.

“The current modelling that informs closure and rehabilitation planning for spoil piles and voids, provides mine operators with uncertain information and may be overly conservative and expensive.

“The methodology we have developed with the support of ACARP will equip them with more reliable, evidence-based predictions for the salinity loads of their spoil piles.

“While we have tested the modelling on spoils in natural conditions, we are now at the point where we want to  advance to field trials, where conditions like water chemistry and volume are different.

“Queensland has a world-leading approach to rehabilitation, and we are keen to collaborate with the state’s coal mining industry to advance techniques and knowledge around the rehabilitation and closure of spoils and final voids.”