Restoring river health through mine rehabilitation
At the historic and abandoned Mount Morgan Mine site in Queensland, Heritage Minerals is implementing an innovative, multi-faceted approach to combat severe acid mine drainage (AMD) and restore downstream river health.
Heritage Minerals and its partners are at the very early stages of a long-term environmental rehabilitation journey to remove legacy risks and contaminants in waterways downstream from the abandoned Mount Morgan mine, which rests in the Dawson sub-basin of the Fitzroy Basin, which drains into the southern portion of the Great Barrier Reef.
Even before production starts later this year, Heritage Minerals and partners are making new investments and initiating new activity which is already improving downstream waterway health and reducing long-term environmental risks facing the catchment.
Historically, the site has been plagued by severe acid mine drainage (AMD), heavily polluting the downstream Dee River and impacting the broader Fitzroy River catchment.
Heritage Minerals is investing $250m and will use proprietary technology to process 2 million tonnes of legacy tailings annually. This extracts valuable residual gold and copper while permanently removing toxic waste from unlined, historic stockpiles.
This re-commercialisation of the mine site will enable rehabilitation of the site that otherwise remains a major contingent liability for the State of Queensland and the environment.
Heritage Minerals has already made a number of major investments well before production. The company constructed a dedicated cofferdam to separate the Open Cut Pit from Sandstone Gully. This infrastructure isolates freshwater flows from contaminated areas, making site water management far more efficient. Paired with high-capacity pumps, this reduces the mine pit freshwater catchment by more than 40%, drastically mitigating the risk of uncontrolled, toxic overtopping events during heavy wet seasons.
Also, under contract to the Queensland Government’s Abandoned Mine Land Program, Heritage Minerals operates the on-site Water Treatment Plant and has been expanding treatment rates. This facility neutralises highly acidic pit water and intercepts contaminated seepage before it can overflow into the downstream ecosystem. The increased environmental flow is already showing remarkable improvements in downstream waterway health.
The company has implemented a comprehensive environmental monitoring program. They routinely sample stream and groundwater quality down the Dee River and into the Don River to closely track baseline waterway recovery. This is paired with efforts to work with partners such as Mount Morgan High School to inform students about the science behind the investments and the benefits that are being sought.
The increased environmental flow is already showing remarkable improvements in downstream waterway health.