|Spiderman: Geotechnical specialist Adam Warren descends |
after chipping away loose rock from Cathedral Cove archway
Thuds resonated through the majestic cave as pieces of ignimbrite rock fell about 15 metres to the bleached sand below.
Hard hats were compulsory inside the cave's exclusion zone as Warren and colleague Raphael Lemgruber, suspended from ropes, scanned the rock face for loose rock to remove.
The cave was closed in April last year because of falling rock, and yesterday the geotechnical specialists assessed the risk of more falls, "scaling" loose rock inside and out.
Tonkin & Taylor geologist Jason Kelly said it was too early to say if the archway would be open to beach-goers this summer but said the two-day investigation would help inform any decision.
"Obviously people's health and safety is our priority but the final decision to reopen it will be made by the Department of Conservation," Mr Kelly said.
More than one cubic metre of rock was removed on Monday.
"Rather than wait for this material to come down we've decided to pre-empt things. But we also have to be sensitive and don't want to go tampering with it too much.
"With any natural feature it's hard to predict what will happen because it's constantly evolving. I come down here often and each time I notice changes."
Avalon development and project manager Kip Mandeno said: "The biggest challenge we face is public relations. The beach was packed on Monday and so you've got to keep people away from the site but also explain what is happening because it's obviously a very important site."
Mandeno said abseiling allowed his colleagues to do the work a lot more quickly than they would if they used scaffolding.
"If you came down to the beach and tried to access the area using scaffolding you'd be here until Christmas."
Haka Tours guide Si Leonard said he hoped the cave would be reopened in time for the summer tourist influx, although he said most visitors were happy just to visit "such a gorgeous beach".