The use of high pressure water jets to remove rock impinging on the shield of tunnel boring machine (TBM) Florence at Tantangara is continuing.

This technique, conducted by specialist contractors since 21 May, is working well, with a device mounted on the cutterhead directing a high-pressure water stream at the rock, which breaks apart and disintegrates.

We halted TBM Florence’s excavation of the Snowy 2.0 headrace tunnel in extremely hard and abrasive rock conditions on 16 May. Cutter disks on the edge of the cutterhead wore down very quickly and this, coupled with a curve in the tunnel, caused rock to pinch on the TBM’s shield.

We made the decision to stop tunnelling to ensure we did not damage TBM Florence.

The Snowy 2.0 project teams are monitoring progress of the rock removal so we can restart excavation.

We expect variable ground conditions to continue ahead of TBM Florence in the headrace tunnel, which will connect Tantangara Reservoir with the 2,200 megawatt Snowy 2.0 power station.