Resin in the moist mix technology is being used to recover up to 3200 tonnes of lead and 4500t of zinc in river and creek sediments around Port Pirie in South Australia.
Developed by InnovEco Australia, RIMM technology has already proved effective in recovering 90% of copper tailings, compared to 75% recovery with traditional heap leach methods.
Researchers from the University of SA have partnered with Flinders Ports, environmental consultants COOE, the SA Environmental Protection Agency and the University of Adelaide in a $1.7 million study of the technology.
The town of Port Pirie has hosted Nyrstar's lead and multi-metals smelter for more than 130 years.
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Over that time airborne lead-contaminated dust produced during smelting operations has swept over the city and surrounds to contaminate the environment.
The risks posed to human health, animals, marine life and the local habitat are immense.
Nyrstar and the SA government have monitored the blood lead levels of the town's children and pregnant women for the past decade, as part of the Targeted Lead Abatement Program.
The 2023 report shows the number of children in Port Pirie with elevated lead levels had doubled in just a year.
According to SA Health, zinc, lead and cadmium levels in the 15km surrounding Port Pirie are significantly higher than guidelines issued by the National Environment Protection Council.
The worst affected areas are the Port Pirie River, river mouth and First Creek, which all have high surface sediment concentrations of lead, zinc, copper, cadmium and arsenic.
The contamination limits species diversity and leads to biomass decline.
The contaminated sediments are also costing Port Pirie's port about $4 million a year in lost revenue because the contamination makes it difficult to dredge the shipping channel.
Flinders will provide access to the Port Pirie River sediments to help researchers obtain sample material.
Flinders Ports assets and engineering manager Guy Tuck said the port's options for recovering mineral deposits had always been limited, which in turn led to a need for more sustainable dredging, recovery and disposal strategies.
"Flinders Ports are proud to be involved in this partnership that will further investigate sustainable options for the reuse and disposal of dredge material from the Port Pirie River," he said.
Project lead associate professor Larissa Statsenko said the RIMM technology could potentially recover up to 3200t of valuable lead and 4500t of zinc in river and creek sediments around Port Pirie.
Applying the technology could also rehabilitate the environment by removing toxic compounds such as arsenic and cadmium from contaminated sites.
Statsenko said compared to existing rehabilitation technologies, the RIMM process was highly efficient and recovered almost all metals in a single step, while consuming less water and reagents.
"It is far less expensive than traditional mineral extraction methods, which require multiple steps to separate water from solids to filtrate the sediments," she said.
"This project has a silver lining. It will not only clean up the environment, helping it on the path to recovery, but also unearth millions of dollars' worth of valuable metals in the process."
