• Client: SLA/MPC
  • Value: $20M
  • Completion date: January 2024

Overview

The Molonglo 3 132kV Transmission Line Relocation Project was a key project to enable the future development of Whitlam Stages 3 and 4. The project involved the total installation of 80km of (6-way and 12-way) conduits across a 9km alignment. The project site is located between William Hovell Drive and the Tuggeranong Parkway, an area of land north of the Molonglo River and west of the National Arboretum Canberra.

The civil works consisted of:

  • Preparation and implement of management plans and traffic control plans.
  • Site establishment including sheds, access tracks, environmental controls and tree clearing.
  • Installation of 2,500m of underbored conduits at a number of locations including the encasing sleeves and pressure grout installation.
  • Installation of 24,500m of open trenched conduits at all other design locations including excavation, laying of conduits and backfill of the trench using thermally stabilized sand.
  • Construction of 28 jointing pits and coordination with EvoEnergy on cable hauling and backfill of pits.
  • Installation of 54 communications pits.
  • Construction of 2.7km of two-coat flexible pavement.
  • Construction of access roads, stormwater crossings, fencing and other miscellaneous civil works.
  • Reinstatement/re-seeding approximately 166,000m2

The project involved the management of many project-specific complexities including variable and undulating topographical settings, numerous road and creek crossings, and environmental and heritage
constraints all in the midst of a third consecutive La Nina event. The M132KV relocation project also represented the first time 132KV powerlines would be re-located underground in the ACT at scale which presented a number of design and construction challenges which could only be solved by a collaborative approach between all stakeholders. Further adding to the technical complexity was the interface between separate contracts with civil works undertaken by Wodens, and separate contractors for cable installation, cable joining, and the future substation site. Wodens ability to manage these multiple interfaces and competing priorities was evident in responsiveness to assist the client by improving access for the cable haulers, constructing a laydown area and providing hardstand areas at each of the cable haulage pits suitable for 18-tonne cable drums.