Sand supply not dependent on continued mining of Pakiri and Mangawhai sea floor

 

13 May, 2022

Following the decision from Auckland Council to refuse an application to extract sand from the Pakiri-Mangawhai coast for the next 30 years, the scaremongering from the vested corporate interests has started. The CEO of the Aggregate and Quarry Association, Wayne Scott, has claimed it will create a crisis in Auckland's construction sector. Opponents of the sand mining however disagree.

"We can expect to see adjustments within the sector as the supply from McCallum Bros' Pakiri operation winds down," says Ken Rayward from the Save our Sand (SOS) Mangawhai Pakiri collective. "However, there are alternatives, and we cannot continue to mine sand from this vulnerable marine ecosystem."

McCallum Bros themselves have raised the prospect of Kaipara Harbour as an alternative. This area can provide a replenishing resource whereas the Pakiri sand deposit is finite. According to McCallum's own expert, the volume currently extracted from the Kaipara is 640,000 tonnes less than what is already consented for removal, considerably more than the 406,800 tonnes that will be lost from Pakiri.

"Scott suggests that bringing sand in via barges to the existing McCallum Brothers depot will generate 100 extra truck movements to the Auckland CBD a month, however this also seems excessive," says Rayward. "It is much more likely that trucking would take place directly to ready mix plants from the new source. This would release the valuable Hamer St site on the western reclamation to more intensive use and reduce the volume of trucks currently driving in and out of the CBD."

There may be increased transport costs, but this will depend on the source of replacement sand and where it is distributed. It will be much less than the cost of double handling it into downtown Auckland and out again.

"Sand is only a small part of the concrete supply chain, and we do not expect a significant change in the delivered cost and negligible impact on project costs," says Rayward.

While there may be minor differences in sand quality, the construction industry does not appear to discriminate among deposits as implied by Scott. In Waikato and South Auckland most sources are land-based marine or fluvial sands.

Underpinning the application by McCallum's is a strong expectation that recent growth in Auckland will be sustained at historical levels, however this is looking increasingly unlikely. A cyclical downturn in migration has been exacerbated by Covid-19 and looks like continuing for some time, ultimately lowering housing demand well below recent projections.

Beyond that, climate change is calling for a rethink of major infrastructure projects, including the contribution of concrete-intensive developments to carbon emissions.

"The council has taken a brave and necessary decision in the case of Pakiri sand mining," says Rayward.

"Reduced demand, changing economic conditions, and climate change are likely to fully justify it, and on top of this we need to preserve a highly sensitive and vulnerable coastline."

PHOTO/JULIA WADE

An alternative sand source such as Kaipara Harbour can provide a replenishing resource whereas the Pakiri sand deposit is finite.