A Northland quarry is supplying a staggering 60,000 tonnes of basalt boulders to be used for foreshore and wave protection in Napier as part of a new $147 million wharf construction.
The gigantic armour rocks are loaded on trucks at Puhipuhi Quarry, north of Whangārei, and transported to the Heron Ship Repair yard on Lower Port Rd from where they are being put on a barge and ferried to Napier.
Heron Ship Repair is part of Auckland-based Heron Construction which bought Ship Repair New Zealand in April 2018.
The company was doing dredging work in Napier when it was asked to supply the boulders as part of the port 6 project — construction of a 390-metre wharf that will allow Napier Port to reduce congestion and to bring in larger vessels.
Auckland-based HEB Construction is working on that project and has subcontracted the supply of boulders to Heron Construction.
Heron Ship Repair managing director Greg Kroef said the ferrying of boulders down to Napier started about a month ago and so far, two trips have been done while a third load would leave Whangārei on Sunday.
"We have 20 trips to do and barge is the most convenient and cost-effective way of doing it. A truck and trailer load may take 28 tons while one barge takes 1000 truck loads in one trip."
The average weight of one rock is six ton and the barge takes about three days to arrive in Napier in good weather conditions.
The barge is owned by Heron Construction.
It's the second time Heron Construction has supplied boulders for a major construction project. The first was in 2015 for Ports of Auckland.
Kroef said because the area in Napier was restricted in terms of space, boulders would be sent as and when required and the last trip should be concluded by the second quarter of 2021.
There were not many basalt quarries in New Zealand like Puhipuhi was that were in close proximity to water and delivered the best rock armour, he said.
"If we didn't have a facility up here, Napier Port would have had to look to another place for the rock armours, and then we have two loaders on hire from Porter Hire so there's an opportunity for local businesses to benefit from what we are doing," Kroef said.
When his company bought Ship Repair NZ, it not only retained all the employees but grew the latter's workforce from 41 to between 55 and 60 at present.
"We have an ever-growing fleet of vessels that need repairs and maintenance and so we were looking for some land to buy, with water access to be able to do work on our vessels.
"That's when we were made aware that Ship Repair NZ and land were being sold as a package. It's a good fit for us. We see it as an extension of the marine work we are involved in," Kroef said.