By ROSALEEN MacBRAYNE
Dangerously unstable rock - 500 tonnes of it - on Mauao (Mt Maunganui) means the Bay of Plenty landmark has had to be isolated.
The campground, hot pools and surf club at the foot of the Mount have been evacuated for a week.
Explosives experts are to blow
up huge boulders near the summit on Thursday, because authorities fear they present "a significant and immediate risk of falling".
The biggest stone to be removed is 50 tonnes.
Hillside rocks were destabilised in January after the latest of periodically destructive fires on Mauao.
In March, a 17-tonne boulder on a ledge near the top of the mountain was jemmied off by professional abseilers using crowbars. It crashed through bush on the seaward face, breaking into several pieces that landed on a grassy flat.
Geotechnical engineers, who stepped up their monitoring of the Mount after the fire, reported the latest risk nearly two weeks ago.
During a routine inspection they found one critical boulder had moved several millimetres over the past six months and only half of it was balancing on another rock.
The total 85cu m area of unsafe rhyolite is about the length of a car and trailer.
Tauranga District Council officials say the rockface is a serious hazard and a minor earthquake could trigger a landslide.
They emphasise that public safety and the well-being of the operations team are paramount and no risk will be allowed while the $100,000 logistical exercise to remove the hazard takes place over the next six days.
People have been urged to stay away from the area immediately below the mountain and a wire fence is in place along the frontage of Adams Ave.
About 30 shipping containers are being used as a barrier around Mauao's eastern base to provide 342 metres of protection from stray rock fragments.
Security guards are on duty round the clock.
Engineers abseiling from the summit to the rockface will drill a series of holes into the boulders to insert explosive charges, linked by wires.
The explosion has been designed to be detonated from above so that the large stones will break up as they cascade down the mountain and land in paddocks at the base.
Mauao is a culturally sensitive icon for Tauranga iwi Ngaiterangi, Ngati Ranginui and Ngati Pukenga. A kaumatua performed a karakia (prayer) over the rocks late on Thursday.
More than 350,000 people a year walk the base track and others run around or climb the popular Mount.
By ROSALEEN MacBRAYNE
Dangerously unstable rock - 500 tonnes of it - on Mauao (Mt Maunganui) means the Bay of Plenty landmark has had to be isolated.
The campground, hot pools and surf club at the foot of the Mount have been evacuated for a week.
Explosives experts are to blow
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