Stanwell Corporation Limited (Stanwell) needed to increase the capacity of the ash storage area (ASA) to accommodate future ash generation volumes resulting from its 1 460 MW coal fired power station, located 22 kilometres west of Rockhampton in Central Queensland.
Aurecon was commissioned to complete the detailed design and documentation of the Stage 3 embankment extension of the ASA in accordance with Department of Environment and Heritage Protection (DEHP) Regulated Dam requirements. The design package also included the design of the associated evaporation pond and seepage containment liner, as well as providing contract administration services during construction. Aurecon has subsequently completed the detailed design of a proposed upstream lifting programme and the development of an ash management plan to provide a whole of life ash storage strategy.
The site subsurface profile comprised braided and interbedded alluvial channels, resulting in highly variable materials over the ASA footprint. Based on the geotechnical investigation results, a generalised profile was modelled and Aurecon adopted a flexible construction methodology in design. This flexible methodology worked well during construction as design amendments were able to be carried out rapidly and efficiently.
Aurecon’s solution to issues encountered during construction allowed the project to be completed within the set timeframe and achieved the target environmental performance outcomes. The expansion upgrades have enhanced capacity, accessibility, and environmental management controls for Stanwell.