NZ quarry business to make own sand to solidify concrete supply

"We take big rocks, and make them into small rocks." That's how Steve Riddell of quarry operator Kaipara Limited described his core business.

But that's about to change.

In April, newly purchased crushing, sifting and washing equipment will swing into action at Kaipara Limited's Brookby Quarry in East Auckland.

"We'll be taking big rocks and making it into sand," said Riddell.

It's a big move for one business, and for the whole industry.

"It's certainly significant," said Wayne Scott of the Aggregate and Quarry Association. "It's the first at-scale manufactured sand operation in New Zealand."

Kaipara Limited's made the move in response to continuing challenges from environmental groups to the traditional dredging of sand from coastal areas and riverbeds.

"We identified some time ago that there was ongoing risk associated with continuing to extract natural sand, particularly from rivers and the sea, from an environmental perspective," said Riddell. "We felt it necessary to ensure that our clients got continuity of supply and had a viable alternative."

New Zealand has plenty of natural sand. But only some of it is of the right quality, and in suitable locations, to be mined to make concrete, of vital importance to the construction industry.

A leading supplier of sand to the Auckland market, McCallum Bros Ltd is currently waiting for the outcome of an appeal to the Environment Court. The court's restricted the company to dredging about a third of the amount of sand it usually takes from near Pakiri Beach, north of Auckland.

One of the groups opposed to the dredging is Friends of Pakiri Beach.

"We say it's relatively straightforward, " said Nick Williams of the group.

"If you're constantly dredging sand resource in an ocean it's bound to show up somewhere in adverse effects."

The Aggregate and Quarry Association said it's an issue for the whole industry.

"It's just getting harder and harder and harder to get consents to actually extract sand," said Scott.

The association said that threatens the supply of concrete to the country's biggest market.

"In Auckland we're on a knife's edge right now," he said.

For now, Kaipara Limited said its manufactured sand will complement the natural product, but it believes it will eventually replace it.

"I think in the long term that's inevitable," said Riddell, pointing out that manufactured sand is now widely used in Japan and China.

Kaipara Limited has spent more than $12 million on the first stage of its sand manufacturing plant. It aims to produce 300,000 tonnes of sand a year. Depending on demand, it has plans for a second stage. Together, that would produce up to 45% of the sand needed for the Auckland market.

The company said its Brookby quarry could produce sand for 100 years. Its Smythes Quarry, in Waikato, could last 1000 years.

"It sounds like a great improvement to me," said Williams of Friends of Pakiri Beach.

"If it means there's going to be less sand mining in pristine coastal environments."

Economics commentator Bernard Hickey said Kaiapara Limited has made a good strategic move.

"This company realises the shortages that are developing globally, and can see an opportunity in New Zealand to create sand that is not hostage to environmental control."

He adds there are also benefits in reducing the industry's carbon footprint.

"Sand is very expensive and heavy to transport. A lot of it is done with trucks and diesel powered trucks," he said. "Creating the sand close to where it's needed in the likes of Auckland will be a good way to use less resources."

Kaipara Limited is not alone in exploring the potential of manufactured sand. Another company, Kayasand, has a development plant in Waikato.