Slip on the Tapu-Coroglen road. Photo / Supplied
The Tapu-Coroglen Rd remains closed due to the large slip about 10km from Tapu.
Thames Coromandel District Council said the slip was approximately 30m wide along the road on the face of the slip with the slip occurring both above and below the road.
Initial site assessment found the risk was too great to allow access to or around the slip, with material still continuing to move.
Closures are in place on either side of the slip.
Properties can be accessed from either end, Tapu or Coroglen, however, detours are large for residents to travel to the other side of the slip, the council said.
Borehole testing has been completed at the site and has identified the need for further testing. Existing bookings for the borehole equipment were changed around to allow Tapu-Coroglen to be tested as a priority.
The initial tests have shown what appears to be a weak strip of material between two areas of stronger rock. There may also be a sub-surface flow of water running through the weaker rock that has caused the erosion of the slip at the base, and will need to be addressed in the permanent repairs, the council said.
Results of the borehole test will be used to decide the next steps, but due to the weakness of the underlying material and possible sub-surface flows the council did not believe that a retreat into the cliff face was possible for a temporary solution.
Prime Minister Chris Hipkins visited the slip during a visit last week to assess the storm-ravaged region’s infrastructure first hand, concluding “we know we have a big job ahead of us”.
Meanwhile SH25 is now open between Hikuai and Opoutere with stop/go traffic management in place to light vehicles only. This is subject to change and the road may close without warning.
Work continues towards a solution for the SH25A slip, with temporary access tracks now in and a geotechnical drilling rig currently at work on site.