The future of sand mining in NZ

Thursday, 7 June 2018

Summers spent at the beach are an intrinsic part of growing up in New Zealand. But what happens when those beaches run out of sand?

It is the natural resource we consume most of worldwide, after air and water, and word is it's starting to run out.

Sand is being described as one the most important commodities of the 21st century.

It's what modern cities are made of; the main ingredient in concrete buildings and asphalt roads, computer screens and microchips.

Extracting sand is estimated to be a US$70 billion global industry according to the United Nations, and more than 40 billion tonnes of sand and gravel are estimated to be extracted every year.

Poyang Lake used to be the biggest freshwater lake in China, now it's the biggest sand mine in the world.

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More than 40 billion tonnes of sand are extracted around the world every year, some legally, and some not.

While the world may seem to have an abundant supply of this sought-after commodity, soaring demand has seen beaches and riverbeds in some parts of the world stripped, to devastating effect.

In Indonesia, more than 20 islands are believed to have disappeared in just the last 20 years due to sand mining.

Countless fish and birds are being killed by river sand mining in India, while miners have torn up hundreds of acres of forest in Vietnam to get at the sand underneath, according to investigative journalist Vince Beiser.

The L.A.-based writer is about to publish a book about the global market for sand; a market he says has been fuelled by an explosion in urban growth, especially across the developing world, over the last 20 to 30 years.

'Today there are four billion people living in cities … cities are growing at a rate and on a scale that has never happened before.

People around the world are waking up to the fact that we need to protect our finite sand resources.

'When you have development going on at such an incredibly rapid pace, and weak laws protecting the environment, then you have people just stripping riverbeds and beaches bare to sell those sand grains to developers, to people who are building Shanghai and Mumbai and so on.'

Desert sand is not suitable for use in construction materials like concrete (its wind-shaped grains are too fine), so sand shaped by water has become the grain of choice in many countries where development is booming.

In China, sand mining in the Yangtze River caused the river's banks to collapse, taking out people's homes and farmers' fields, Beiser says.

Legal extraction moved to Poyang Lake, the biggest freshwater lake in China, and now the biggest sand mine in the world, he explains.

'There are a lot of places where all the sand you can get at easily is gone.'

'Companies are having to go ever further, go to greater and greater lengths and cause more and more damage to extract the stuff.'

How widespread is sand mining in New Zealand?

Sand is extracted from New Zealand beaches, ports, quarries and rivers, but just how much and where is not easy to sum up.

There are are no central statistics on sand mining.

The closest thing is a voluntary survey of quarries by New Zealand Petroleum and Minerals, which puts the combined amount of sand, rock and gravel produced by quarries, at around 30 million tonnes a year.

Regional councils, asked how many sand mining activities were consented for in their areas, reported between zero and 26, ranging from harbour dredging, to dune extractions for commercial purposes and flood defences.

Perhaps the best indication is the concrete industry, where most of the sand extracted in New Zealand is understood to end up.

Roughly 3.5 million tonnes of sand a year is used to make concrete, which is being produced in near record amounts.

Bulldozers drag new sand over old to help prevent further erosion on Brophy's Beach, Whitianga.

Sand extracted from the sea, including some from harbours, accounts for about 15 per cent, according to the industry body, Concrete NZ.

Some of the rest is dug up from rivers, but most is manufactured sand, known as fine aggregate, which is made from crushed rock.

Compared to the amount of sand used in concrete, little of the country's sand is shipped offshore.

However last year saw a big jump, with 4000 tonnes of silica and quartz sands worth $1,769,980 exported, compared to 97 tonnes the year before.

Statistics New Zealand said the increase was mainly due to exports to New Caledonia. But where it was extracted from, and who by, was confidential.

Big players

Two long-standing sand mining operations north of Auckland are allowed to dredge more than 380,000 cubic metres a year combined.

There's consent for 308,000cu m per annum at Kaipara Harbour, where sand has been pumped aboard barges for nearly 30 years. And 76,000cu m can be taken a year in water 5 to 10 metres deep in the Mangawhai-Pakiri embayment in the northern Hauraki Gulf.

The iron sands mine in Taharoa had an estimated 300 million tonnes when it first opened in 1973.

Coastal permits allowing the company McCallum Brothers to dredge at Pakiri were extended in 2009, when the High Court upheld an Environment Court decision that natural sand replenishment would compensate for sand taken.

The science is still being argued.

Pakiri is a finite sand system, according to Jim Dahm, who has worked as a coastal scientist for more than 40 years.

'It's got all the sand that it's pretty much ever going to get, and anything you draw is going to be replaced ultimately, in the long term, by erosion of the dunes.'

The beach sands moved onshore at the mining site after sea level rose to its current elevation about 7500 years ago, after the last glaciation, but that net onshore supply has now largely ceased, the Thames-based consultant said.

If shell content from dying organisms was coming into the beach system at a rate of nearly 100,000 cubic metres a year, as argued by some, the beach system would be far bigger than it is, he maintained.

While sand was being replenished in the 'humungously large sand system' at Kaipara Harbour on the west coast of the upper North Island, drawing sand from east coast beaches was 'nuts' in the face of sea level rise.

'For east coast beaches, the figures generally vary between the potential for 20 metres to 50 metres erosion with one metre sea level rise and we're expecting one or two metres as a minimum.

'So the last thing you want to be doing is sucking sand out of it.'

McCallum Brothers declined to comment, referring to the Environment Court decision and resource consent requirements.

A lot of the damaging sand mining in New Zealand, however, was a thing of the past, Dahm said.

It doesn't seem like a lot, but the area under consideration would cover downtown Auckland.

'Generally in New Zealand, we became aware of the issues of sand mining in the 60s and 70s.

'There was a lot of sand mining done in NZ in the early 1900s, around Manukau Harbour, Thames coast, Coromandel beaches, Auckland beaches, a lot of irreplaceable sand was removed,' he said.

'So most of our really bad sand mining is historical.'

Iron sand meanwhile has been mined onshore in New Zealand for more than 40 years.

The black sand contains the mineral iron ore, which is extracted to make steel.

The Taharoa Ironsands mine in Waikato has been reported to export more than $150 million worth of sand a year, mostly for use in factories in Asia.

When the mine opened in 1973, it gained access to an estimated 300 million tonnes of iron sand concentrate. In 2013, it was forecast to have another 15 years to run.

The Waikato North Head mine produces up to 1.2 million tonnes of iron sand a year, for use in the New Zealand Steel mill at Glenbrook. The deposit is estimated to contain more than 150 million tonnes.

A new era of mining?

New Zealand now faces the prospect of iron sand mining offshore.

A High Court decision is pending on plans to mine 50 million tonnes of iron sand a year from the seabed off the coast of Taranaki.

Last year, the Environmental Protection Agency granted Trans-Tasman Resources Ltd marine consents to mine an area of seabed in the South Taranaki Bight of nearly 66km2 to extract iron ore for export.

Eleven parties appealed against the 35-year consents at a hearing at the High Court in Wellington that wrapped up in April.

It is the second time TTR has applied for marine consent to mine the South Taranaki Bight. Its first application was declined In 2014.

Last year, the EPA granted the consents subject to conditions, including that two years of monitoring had to take place before the company was allowed to begin mining in the planned area, 22km to 36km offshore from Patea.

Under the plan, a remote-controlled dredge would vacuum sand from the sea bed in depths between about 20 metres and 42 metres, to a processing ship where the iron ore would be extracted.

It was planned that about 90 per cent of the material would be returned to the sea.

Opponents said, among other things, that the noise and sediment plume would cause birds and marine animals to avoid the area, and would result in long term, if not permanent, damage to the environment and cultural concerns of Māori.

TTR said the area was already intensively fished, had gas and oil installations, and was a rugged environment subject to naturally occurring sediment flows from rivers.

One of appellants, the group Kiwis against Seabed Mining (Kasm) says not enough is known about the impact of the mining.

It fears approving the project would set a precedent, opening the floodgates to mining in New Zealand waters.

'This would be the first time seabed mining is allowed in NZ … why should NZ be the testing ground?' spokesperson Cindy Baxter said.

Seabed mining, globally, is in its infancy.

When TTR first mooted its plans, other companies were lining up in the wings, Baxter said.

Information from New Zealand Petroleum & Minerals showed, in 2012, more than a dozen prospecting and exploration permits had been issued to other companies, Kasm research indicated

'If it went ahead, it would be a massive experiment,' Baxter said.

Three other exploration and prospecting permits are currently active in New Zealand waters.

Cass Offshore Minerals Limited has two exploration permits, one for iron sand in Taranaki, and one for ilmenite off the Bay of Plenty.

The company wouldn't speak to Stuff.

Information on its website says New Zealand has the fourth largest continental shelf land mass in the world.

'Its volcanic geology has made the waters offshore New Zealand an untapped mineral resource target of unprecedented scale.'

Information about Vince Beiser's book, 'The World in a Grain: The Story of Sand and How It Transformed Civilization' can be found at https ://www.penguinrandomhouse.com/books/537681/the-world-in-a-grain-by-vince-beiser/