The final stages of works are underway to cap 230ha of mining land at two waste rock storage facilities used during Handlebar Hill open-cut operations near Mount Isa between 2007 and 2014.
Glencore’s Mount Isa Mines began work on rehabilitating the sites in 2017 and since then almost six million tonnes of earth has been moved as part of reshaping and creating a 1.5m thick cover layer of non-acid forming (NAF) capping material over the sites.
The project at the Handlebar Hill and Magazine waste rock storage areas is being undertaken in collaboration with construction management team Infra-Struct and contractor Queensland Building & Civil (QBC).
Queensland Metals superintendent − HSEC environmental long-term planning Sarah McConnell said rehabilitation works were an essential part of life of mine planning and social licence to operate.
“We’re committed to minimising environmental impacts from our operations and are undertaking about $50 million worth of work in 2020 and 2021 to restore mined land across our Queensland operations,” she said.
“We will be looking at the success of this project to set the benchmark for other rehabilitation works across our Queensland Metals business.”
The capping project incorporates much more than just earthworks – with a detailed geochemical and geotechnical field investigation project undertaken to provide input into the design.
Twenty-six drainage channels stretching 4.1km have been used to protect the final cap from water run-off during storm events.
The seasonal runoff water will be directed into the site’s sedimentation dams, which were expanded by an additional 550 megalitres as part of the project.
Drainage is due to be completed across the site over the next six months.