Cape Lambert trenchless success
Project Owner: Rio Tinto
Project Head Contractor: NRW, Tunnel Boring
Project: Stormwater drainage lines
One of the largest ports in the Pilbara region is Rio Tinto’s Cape Lambert. Trains travel in from Rio Tinto mines throughout the region, carrying around 80 million tonnes of iron ore per year into Cape Lambert for processing and ship loading. An integral part of the upgrade project was the extension of the “Sam’s Creek” drainage lines, which run under the existing rail lines allowing the release of stormwater during the wet season. The rail lines needed to stay in constant operation throughout the construction works in order to ensure the continual loading of ships.
Stopping the productivity was not an option, making trenchless installation the only choice. The solution required two rows of 2100 mm internal diameter pipes with approximately 100 meters length each. Jacking pipes with an outside diameter of 2250 mm and a stiffness of SN 32000 were specified for this purpose. With the soil being hard and rocky, the initially calculated jacking force added up to 7850 kN. Thanks to the smooth outer surface of the pipes, the actually applied jacking forces were much lower than expected. The substantially smaller outside diameter as compared to an alternative concrete pipe had the additional benefit of allowing increased ground cover beneath the rail line, reducing both risk and installation time. Furthermore, the lead-time for GRP pipes was substantially shorter than that of locally supplied concrete pipe, and given the tight timeframe for the project, GRP jacking ppes proved to be the best solution.
The installation set a new record in terms of the largest diameter jacking pipe ever installed in Australia, and it paved the way for similar projects in the ever growing mining industry in Australia. The Rio Tinto drainage system was also used as an opportunity for creating cultural awareness: Local artists were invited to paint the pipes in the artistic style of the traditional landowners. The imagery is supposed to bring good fortune to the land and the pipes have become truly part of the local landscape.