Newcrest is researching innovative ways to extract greater value from mining operations by retrieving copper and gold from low-grade or residual ore.
The project focuses on recovering a metal ion-enriched solution from the ore for further processing to extract the gold and copper and process it for sale.
While the technique has long been used to recover evaporites and potash and is commonly used in uranium mining, there are few examples of in-situ mining being used in hard rock applications, such as gold and copper mining.
This technique also eliminates waste rock and dramatically reduces water consumption, improving energy efficiency and creating a more sustainable way to extract high-value minerals.
Newcrest has partnered with experts from Curtin University, Monash University, CSIRO and engineering consultancy Hatch to research new ways to advance the method. As part of the research, the ore is processed through a bottle wash and put into a large container, where it is rolled in a chemical test solution for seven days.
Samples are taken throughout the process to see how effective the solution is, how much copper is being extracted and over what period of time.
The work is not without challenges, with breakthroughs required to develop a mix of chemicals to most effectively extract precious metals in an environmentally sustainable way.
In the case of gold, we are seeking lixiviant chemistries that don’t use cyanide to reduce the impact on the environment.
The team also must determine the best way to access valuable minerals in the hard rock, then maximise their recovery.
While researchers believed the approach might be 20 years away from implementation, Newcrest hopes to be an early adopter and industry leader in this technique.