Sand miner looks to hostile waters off Kaipara

A mining company has turned to a huge sand bank in the often stormy Tasman Sea for a new source to feed Auckland's building industry.

McCallum Bros has lodged applications with the Auckland and Northland Regional Councils for extraction in the ebb tide delta.

This area draws sand carried by coastal currents and is 2km to 4km outside the heads of Kaipara Harbour, in an area known as the Graveyard because more than 100 sailing ships have been lost there.

Director John McCallum said the application was to incrementally build up to taking a maximum of 300,000 cubic metres a year.

This would fill about one-third of Auckland's construction sand needs.

"We think we have come up with a long-term solution for the supply of sand for the Auckland building industry," he said.

Present sand supplies come from inside the Kaipara Harbour and Pakiri - on the east coast north of Warkworth - and the Waikato Valley.

Since the 1940s, McCallum Bros have taken sand from the Mangawhai-Pakiri embayment.

But it received a setback in April when it tried for resource consent renewal.

More than 650 people, including residents, scientists, surfers and the local iwi, were against it.

The ARC recommended refusal to the Minister of Conservation after accepting evidence that the resource was not replenished naturally and continued extraction from near the shore would lead to or worsen coastal erosion.

McCallum Bros and Sea Tow have appealed to the Environment Court.

Mr McCallum said the company accepted near-shore extraction at Pakiri would not give a long-term supply and intended to develop the offshore Kaipara resource as an alternative future source.

The 60sq km area of sand in the ebb tide delta was estimated at 12 billion cubic metres and was replenished by tidal currents moving sand up and down the coast.

The project was early in the planning stage.

He believed the proposal would not affect the endangered Maui dolphins, saying there was little marine life in the turbulent area to attract them.

Mr McCallum said the dredge would operate in 5m to 15m of water and would not be as easily seen from shore as Pakiri's dredges. It would be a ship of a type that worked successfully in ocean sand recovery in Europe and the United States.

The ship would take 1500cu m loads to the Port of Onehunga to avoid crossing the treacherous Kaipara Bar and the need for trucks to make a 60km haul to Auckland City.

He played down the hazards of operating a ship in that area, saying it would be beyond the breaker line and weather records indicated about 250 working days a year were possible.

ARC coastal projects leader Andrew Benson said the ebb tide delta appeared to be a good prospect but the main question was its sustainability.

Northland Regional Council harbour warden for the Kaipara Harbour and Ripiro Beach Des Subritzky said the application would be of great interest to people in the area.

"It's a very hostile environment for a ship."

Mr McCallum said there were sharp differences between the proposal and the proposals of overseas mining companies to extract minerals from the seafloor.

They were for deeper waters where the sea floor was more stable and had higher levels of marine life.