Innovative design and solutions for mine water management on an alluvial floodplain

The Curragh North coal mine is located on an alluvial floodplain of the Mackenzie River, in central Queensland, Australia. The catchment area at the mine site is 50,000 km(2) and the site had been inundated during previous floods. Until recently, development of the site had not proceeded due to flooding and water management risks and the difficulties involved in overcoming these risks. PB's innovative design provided solutions to two problems which were deemed critical to the project's viability, namely a sustainable water supply for the mine and cost-effective flood protection. A holistic design approach was used to address the project's water supply and water management challenges: daily water balance modelling of the mine water management system to maximise on-site water harvesting; design of a two-way pipeline to enable exchange of water to and from an existing final void, reducing evaporative losses and on-site dam infrastructure requirements; creation of dams within reshaped spoil piles to maximise the water harvesting potential as the mine expands; design of controlled release points to allow spills to the Mackenzie River only when the river flows are between set limits.