Built specifically for Snowy 2.0 project by CREG in collaboration with the Future Generation JV, the CREC783 TBM, named Lady Eileen Hudson, was commissioned at the main access tunnel(MAT) and has already excavated 1,500m underground, making great progress. The 142m-long, 11m diameter CREG machine is initially scheduled to bore the MAT into the power station complex.

After the 2.7km excavation of MAT, the machine will be dismantled and reassembled near the downstream reservoir to bore the 6.0km tailrace tunnel back towards the power station complex. The challenges faced by this machine are mainly associated with the anticipated ground conditions. The MAT reaches a maximum depth of approximately 750m and therefore has the potential for experiencing stress-induced ground behaviours. To address this, the TBM has been designed with reserved thrust and torque capacity, tapered shields and the ability to over-excavate. The drive also has the potential for experiencing high groundwater inflows, a risk that is exacerbated given the downward drive direction. To sort out these challenges, the TBM is equipped with extensive probe drilling and pre-grouting capabilities, in addition to substantial dewater pumping capacity.