If it will yield big gnarly lumps of shellrock for rebuilding Whanganui's moles then a backblocks Whanganui quarry could be re-opened - threatening walking trails established by a club.

Basil Hooper was Wanganui Tramping Club's prime mover in establishing the Waitahinga Trails in 2012.

He's disgusted the quarry could be reopened without any prior warning from Whanganui District Council to the club or to the public.

"If the quarry became as big as figures suggest to us, it would destroy the access and the trails. We wouldn't persevere, should we lose that access up there," he said.


In 2016 Whanganui District Council gave itself consent to reopen Waitahinga Quarry, reached from Rangitatau East Rd 18km inland from SH3, property/project manager Rowan McGregor said.

The consent was not publicly notified or brought to the attention of Wanganui Tramping Club. With the encouragement of council it has spent "hundreds of hours" establishing the walking tracks.

An estimated 1.5 million cubic metres of shellrock is sitting at the ridgetop, and the 2016 consent can be activated until March 2021.

But before it can re-open the quarry the council has to submit a detailed management plan, and before it goes to that trouble it needs to know whether re-opening the quarry will be in the interests of ratepayers.

A second consent from Horizons Regional Council in 2018 will allow council contractors to spend 10 days finding out whether big chunks of rock can be extracted. That work is out to tender and could be done in late February.

Quarry rock is in short supply in New Zealand, because of the Kaikoura Earthquake, Transmission Gully and Manawatū Gorge road work.

"Is there other rock we can get at all? It's got to be a very hard rock to take the action of the sea up against it," McGregor said.

Whanganui District Council wants the trails to continue. Any alterations needed as a result of re-opening the quarry, such as a new public car park, would be among the costs to be considered in a business plan.


But Hooper says there's "no practical alternative to access if they start clawing their way along that ridge". And an extension of the quarry could take out a viewpoint on the trails' most popular walk, the Chicken Run.

This photograph shows base of the former Waitahinga Quarry, signage for the trails and the high point of the ridge. Photo / Basil Hooper
This photograph shows base of the former Waitahinga Quarry, signage for the trails and the high point of the ridge. Photo / Basil Hooper

It would "decapitate" a 576m high bush-covered ridge that is the highest point between Whanganui and Mount Taranaki, and destroy half a hectare of mature native forest every year.

"The very rock they're after is on the highest point of the ridgeline," Hooper said.

As a tramper, he doesn't think we should do that to our highest land.

He said the effect of re-opening the quarry will be more than minor, consents should have been publicly notified and the club should have been consulted. It's now too late for the club or the public to object.

The club and council now await the result of exploratory work by contractors.