Capricorn Copper is investing $5 million in a pioneering rehabilitation project at its copper site, 125km north of Mount Isa.
The company is using a bituminous geotextile fabric to cap a former tailings dam and a heap leach pad.
Capricorn Copper was faced with a raft of legacy environmental issues when it took over the mothballed Gunpowder site, also known as Mount Gordon, from Aditya Birla in 2015.
“We are rehabilitating one of the old tailings dams on site and one of the heap leach pads from 20 years ago,” Capricorn Copper chief executive officer Brett Fletcher said.
“It will cost about $5 million and we are using all local contractors, with GHD out of Townsville providing the engineering support.”
The cover being used provided a water-proof seal with a lifespan of 1000 years, he said.
“On top of that we lay a metre of growth medium – soil and crushed rock – to revegetate the surface,” Mr Fletcher said.
The tailings dam to be capped off covers an area of about 10ha while the heap leach pad is about 4ha.
Mr Fletcher said the company believed its pioneering use of the Coletanche bituminous geotextile liner from France would not only bring environmental benefits for this site but offer a future direction for other rehabilitation projects.
It was an alternative to the clay cap that would traditionally be used to seal such areas, he said.
“We would have had to find about 100,000 tonnes of clay for the projects we are undertaking, and there is none on site, so there is the (ground) disruption and we would have to transport that total to lay it down,” Mr Fletcher said.
“Obviously environmentally that is not ideal – as well as being costly and time consuming.
“We believe the liner will provide a better environmental solution.”
The project is expected to be completed in August after site works kicked off at the start of the year.
Mount Isa-based Steelcon Cava is carrying out the extensive civil works required for the dual rehabilitation project.
Mr Fletcher said Capricorn Copper was working in co-operation with the Department of Environment and Science on the initiative.
“It’s about progressively rehabilitating the mine while operating it as well,” he said.