Lakes Creek Road Landfill in regional Queensland – which receives most of the waste generated from the local Rockhampton community – was fast approaching its approved regulatory capacity.
The Rockhampton Regional Council desired a 20-year extension of the life of the landfill through vertical expansion. The alternative was to transfer waste from Rockhampton to Gladstone, a city some 110 km away by road, increasing the carbon footprint and expense for the Council due to the long-distance haulage required. A greater number of truck movements on an already heavily utilised road would also have been a burden on the community.
Following a review of the geotechnical data, Golder identified several risks with the potential to significantly affect any extension of the landfill. Particularly, the presence of very soft soils beneath the existing landfill footprint required further site investigations, testing and analysis of the subsurface materials.
Through innovation in design, Golder was able to develop a geotechnical monitoring and waste filling program which increased the landfill site capacity to more than 33 years. Our geotechnical skills and knowledge of soft soil engineering along with an advanced understanding of the use of geosynthetic materials were major factors in the success of the project. By developing an unconventional staged ‘piggyback’ filling plan in conjunction with further stability analysis and applying geosynthetics and natural materials to manage leachate and landfill gases, the vertical expansion of the landfill became a viable option.
Our design, which was adopted by the Council, resulted in considerable gains for the community and the environment. As well as providing ongoing employment for the landfill workforce, the extension of the life of the landfill will generate revenue in the order of AU$250 million through gate fees over the remaining extended life of the facility, which can be used by the Council to fund the ongoing development of the landfill. Improved environmental outcomes are also expected from vertical expansion with geosynthetic lining materials.