The tunnel boring machine (TBM) that was halted last year when a 9-m (27-ft) deep hole formed on the surface above it in Australia’s Kosciuszko National Park will remain in place until the Snowy Hydro project can prove to the New South Wales environment department that moving the TBM will not cause "further damage."

Australia’s ABC News reported that the NSW Department of Planning and Environment (DPIE) said it was investigating the incident and has now placed further environmental conditions on the boring operation.

"Snowy Hydro must prepare a modification report that demonstrates how the project can safely progress without further environmental damage," the department said in a statement.

"Tunnel boring at the Tantangara location is on hold until the department gives approval for operations to continue."

The tunnel being drilled by the TBM named Florence is one of three major tunnels that will form the Snowy 2.0 project, a large hydro-electricity project in southern NSW that is one of the centerpieces of Australia's transition to renewable energy.

Snowy Hydro announced in early May that Snowy 2.0 would be delayed by up to two years and was expected to be fully operational by 2029.
One of the four main reasons cited by the company for the delay was the issue with TBM Florence.

Snowy Hydro said it took its environmental responsibilities "very seriously" and had been working with the DPIE and others since what it called a "surface depression" was identified in December 2022.

"Snowy Hydro has also been working closely with the DPIE to provide a scope of works and to progress a modification of the Snowy 2.0 main works planning approval to allow the rectification of this area and provide assurance around future tunneling works," it said in a statement.

It said it expected to submit its modification report to the department "within a week" and was confident the information would "satisfactorily address concerns around future subsidence issues."