It is the first time in Australia that a TBM will be used to excavate access tunnels for a coal mine.

GHD global technical leader for energy and resources Richard Fechner said: “Anglo American is a key global client for GHD, and this project is a very important and exciting one for our team.

“We are providing a range of services from geotechnical investigations and detailed tunnel design, to reviewing the TBM specification, launch and excavation methodologies, and EPB operating pressures.

“This will enable Anglo American to access the coal seam in a fraction of the time a traditionally excavated drift would take and provide a maintenance-free access tunnel structure for the life of the mine, expected to be 40 years.”

The 8m diameter earth pressure balance TBM will excavate two 1km-long drifts from the surface to the coal seam. One drift will house the conveyor, while the other will be used to transport people and equipment into the mine.

Each drift will have an internal diameter of 7m and consists of a steel fibre reinforced concrete segmental lining. After the first drift is completed, the TBM will be disassembled and extracted, leaving the shield in place.

It will then be reset in a new shield for the second drive. Once the drifts are complete, the TBM components will be retained for use on other Anglo American projects.

GHD has used TBM methodology for a range of recent projects, including the Legacy Way road tunnels in Brisbane, the Sugarloaf Pipeline Alliance in Victoria, the Melbourne Main Sewer and the Epping to Chatswood Railway Line in Sydney.