New tunnelling approach expedites mine development
For the first time in Australia, an Earth Pressure Balance (EPB) Tunnel Boring Machine (TBM) is being used to excavate access tunnels (drifts) for a coal mine in Queensland, Australia.
The new method is designed to help the mine owner, Anglo American, access the coal seam and commence production sooner.
The TBM methodology for Anglo American’s Grosvenor metallurgical coal mine in Moranbah, south-west of Mackay, has been developed with GHD’s assistance in providing detailed design and owner’s engineer services for the project.
Glen Tonkin, Anglo American's Grosvenor Project Director, says, "The TBM tunnelling method will deliver advances in safety, higher quality drifts and faster project development."
In terms of GHD's involvement, Brendan Henry, one of our principal tunnel engineers, explains, "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 to provide a maintenance-free access tunnel structure for the life of the mine, expected to be 40 years."
The 8 m diameter TBM will excavate two drifts – one km long each – 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.
Once the drifts are complete, the TBM components will be retained for use on other Anglo American projects.