Microtunnelling is used for the installation of high accuracy fine grade gravity sewers, storm water systems and outfall pipelines. A variety of pipe materials can be installed including VC, Hobas, Polycrete, Naylor Denloc and reinforced concrete jacking pipes. Tunnelcorp operates Australian manufactured high accuracy laser guided vacuum extraction microtunnellers. These machines are designed by drillers for drillers to the highest standards. The machines have the capacity to drill through rock and once the cutters have worn the whole machine can be retracted to the launch shaft to change the cutter head. These machines have an advantage over slurry machines in that slurry machines cannot retract and require intermediate shafts to be constructed to change the cutters. The vacuum machines have real time, all directional, laser guided steering that is highly accurate. The machines can drill with steel encasing pipe, any type of jacking pipe and free bore in suitable ground conditions. The machine can be retracted from within a steel encasing pipe leaving the encasing pipe in situ to minimise the risk of collapse whilst the cutters are changed or obstructions removed. Tunnelcorp manufactures vacuum extraction microtunnelling machines in its’ own manufacturing facility. The newest addition is a high capacity vacuum unit driven by a 350hp Caterpillar diesel engine powering a 5250 cfm vacuum system capable of drilling to 1200mm diameter.