Dewatering is underway as part of the water management plan at the Mount Morgan mine, near Rockhampton.
The mine is under government control and is being rehabilitated in a complex long-term project, which started in 2000.
The open-cut pit overflowed in late January 2013. This was the first uncontrolled release in the mine’s history.
Controlled releases, to reduce the water level in the open-cut pit and minimise the likelihood of further uncontrolled spills following further rainfall, were done in line with the site´s Contingency Plan, when sufficient dilution flows were available.
A seepage interception system operates on site and captures more than 90% of the subsurface flow from the mine site, also known as seepage. The seepage is pumped back to the open-cut pit for containment, treatment and evaporative loss.
The January 2013 flood event has highlighted the importance of site resilience works and water management systems. To mitigate the risk of overflows from the open-cut pit and to provide a buffer for future rainfall events, water management improvements at the site remain a top priority.
Expert environmental engineering consultants have been assisting the department to develop detailed options on water catchment and treatment, safety and associated rehabilitation works.
Their assessment will provide independent analysis of the potential short, medium and long term strategies for site water management and rehabilitation. Options put forward will be carefully considered by the Government
Within this context, current site rehabilitation objectives are:
- reducing the water level in the open-cut pit, thereby minimising the risk of spills of contaminated water into the Dee River and reducing contaminated seepage from the site
- developing sustainable freshwater diversion systems and improving the site´s fresh water supply, which also supports the water treatment plant
- reducing the volume of contaminated runoff and seepage leaving the Mount Morgan Mine site and entering the Dee River
- progressively remediating the mine site, with consideration of mineralised stockpile relocation or covers as long-term alternatives to AMD interception and water treatment
- reprocessing of mineralised material through the agreement with the mining lease holder (Norton Gold Fields Limited) may support the above, but is subject to commercial considerations
- maintaining access to the site’s significant mining heritage through tourism opportunities.
The Mount Morgan Mine site is located at the township of Mount Morgan, 32 kilometres south-west of Rockhampton in Central Queensland.
Mount Morgan was founded as a gold mining town in 1882. The Mount Morgan Mine operation began in 1882 and ceased in November 1990.
The State took over management of the Mount Morgan Mine in 1993 after operations ceased and the company went into receivership.
The legacy of past mining includes the large waste rock and tailings dumps left over from mining and mineral processing. Off-site impacts occur from ongoing generation of acid and metalliferous drainage (AMD) and seepage of low quality water into the adjacent Dee River.
