Though the idea “can have its opponents”, New Zealand needs a strong supply of sand sourced from coastal and river extraction or quarries to meet demand, says Aggregate and Quarry Association Chief Executive Wayne Scott
Photo by Dmitry Dmitry on Unsplash
Manufactured sand is currently only meeting between 5 and 10% of New Zealand’s demand for sand, most of it going into concrete production.
Manufactured sand cannot replace the need for natural sand in concrete. It will likely form an increasing percentage of supply but it comes at considerable extra cost and like any economic activity, its own environmental consequences.
Most sand manufactured in New Zealand would need to be made from virgin rock or stone as the crusher dust created from making aggregate is used in road construction.
That means a lot of energy either from electricity or diesel. If the sand has to be transported any distance, that further adds to environmental and economic costs.
Naturally-sourced supplies will still be required for many years and New Zealand needs to plan ahead and protect our aggregate supplies – so we can provide affordable houses and continue to build and repair our infrastructure.
Coastal-sourced sand is contentious in New Zealand but in places such as England, which have similar environmental protections, it provides 20% of supply. Most of the sand on coastlines comes from rivers and is replenished.
Until recently, half of Auckland’s sand needs came from its north coast, barged into the city. With this supply now reduced by two-thirds as a result of an Environment Court decision, many more trucks are on the region’s roads.
Some of the alternative sand is river-sourced, which again can have its opponents. Yet removing sand and gravel from rivers is a flood-protection measure which deluged residents, most recently in Tasman, urge their councils to do.
Like many rock quarries, resource consent applications to extract sand from a quarry are often opposed by nearby neighbours.
Councils have to weigh up those voices against the need for a critical resource for the growth of their districts. They certainly shouldn’t believe another solution is at hand. While manufactured sand will likely develop its current market of 5-10% of New Zealand’s sand requirements, it is no magic bullet.
We will need a strong supply of naturally-sourced sand for many years yet.
