At Tantangara in the NSW Snowy Mountains, we’re building critical infrastructure for Snowy 2.0, the major pumped-hydro expansion of the Snowy Scheme.

In the headrace tunnel, specialist contractors are continuing to conduct hydro blasting work to remove rock pinching on the shield of tunnel boring machine (TBM) Florence.

The Snowy 2.0 team stopped TBM Florence in May when extremely hard and abrasive rock conditions wore down cutter disks on the edge of the cutterhead very quickly as it traversed a curve in the tunnel.

In recent weeks we have moved TBM Florence forward in small increments several times and the machine remains fully operational.

The high pressure hydro blasting breaks up and disintegrates the surrounding rock so TBM Florence can navigate the curve onto the straight headrace tunnel alignment.

In the June project update, Snowy 2.0 tunnel engineer Nick Chapman, who oversees tunnel design and provides technical engineering support for construction activities, highlights progress at the Tantangara Reservoir intake and gate shaft, along with underground works to connect the two.

The gate shaft is one of the key structures in the overall Tantangara intake system, which also includes the intake diffuser, tunnel transitions and headrace tunnel.

The main function of the gate shaft is to stop and start the flow of water into the headrace tunnel and power station for maintenance purposes or in the case of an emergency.

Now the gate shaft is excavated, work is focused on the two transition tunnels either side.

These tunnels are well advanced, with the full length of the top heading complete and excavation to the invert on schedule for completion in July.  

The intake is now approximately 45 metres deep – the remaining excavation is being coordinated with work on the third transition tunnel. 

The next stage of the intake earthworks will involve the removal of the temporary “rock plug” and excavation into Tantangara reservoir, to allow water to flow through the intake and into the headrace tunnel. 

That’s something to look forward to in future updates!