UEA Trenchless completed a 300 metre underbore within a copper fabrication facility in Port Kembla. As a part of the refurbishment of parts of the facility, the existing gas main needed to be relocated to make way for new infrastructure. The existing gas main was attached to buildings, concrete ramps and steel structures that needed to be demolished. In order for the refurbishment to proceed, the previous gas main needed to remain in use prior to a plant shutdown to allow the transfer to be carried out. As the facility was in operation since 1912, UEA undertook extensive investigation of the geotechnical conditions and structural elements – both below and above ground – around the vicinity of the underbore. Based on the results of the investigation, UEA proceeded to undertake survey and to design the underbore through existing piles for the concrete ramp and silos.
Using a Vermeer D100 HDD rig, UEA supplied, welded, bored and installed 312 metres of 125mm PN16 SDR 11 HDPE in rock ground conditions. With depths ranging up to twelve metres in rock ground conditions and beneath reinforced concrete slabs, UEA successfully utilised a Digitrack tracking system with varying high signal strength to track the underbore by walkover techniques. In order to undertake the works while maintaining the copper facilities operations, UEA designed and constructed the underbore while setting up on the concrete ramp and utilising a minimal footprint.
Once the underboring works were finished, UEA continued to work with the client to ensure that the connection of the new gas main was successfully completed. Additionally, UEA undertook pressure testing on the installed gas main and completed the works as executed drawings and Inspection Test Plans (ITPs) as part of UEA’s Quality Assurance Accreditation ISO 9001.