Kpone power plant drives complete19 January 2018
Ghana – Cooling lines for a new oil and gas power plant close to Accra called for a microtunnelled solution. Two tunnels, one for sea water intake and the other for outfall were constructed by Coleman Microtunnelling (a subsidiary of Australia’s Bothar Group) using a 2.5m-diameter Herrenknecht AVND2000AB utility tunnelling machine.
The tunnels have an outside diameter of 2.5m and a total length of 2,530m, completed with four separate drives. Two shafts were sunk at the shoreline, then the machine tunnelled through weathered gneiss to the power plant, which was a 545m and 520m distance to the respective shafts. After this, the machine excavated a 1,085m-long tunnel to a seabed recovery point for the intake, where it was recovered at a depth of 17m. Finally it tunnelled a 380m-long parallel outfall.