Background

Winstone Aggregates and Mt Rex Shipping Ltd have been extracting sand from the Kaipara Harbour for over 25 years (Mt Rex Shipping Ltd more than 70 years). Both companies hold resource consents in an overlapping area of the harbour, with Mt Rex Shipping undertaking all extraction activities under both companies consents. This is a joint operation that supplies a significant volume of sand for the construction industry, critical for building and infrastructure and for supporting Auckland’s economic growth.

The sand is extracted using a specialised suction dredge from a 9km2 area to the west of Manukapua Island. The sand is then transported back to Helensville where it is stockpiled at Mt Rex Shipping Ltd.’s site before being sent to market.

History

Consents were granted in 2006 for a maximum combined sand volume of 700,000m3 per year. This is a fraction of the total sand storage on the Tapora Banks (13-31 million m3) and well below the natural replenishment rate, which has been estimated at 2.6 million m3/year.

Strict conditions from part of the consents, which involves annual monitoring of the coastal morphology of the site and surrounding area and biological monitoring of the seafloor every 6 years. This has been carried out by NIWA since 2007.

Historically Winstone Aggregates undertook its own sand extraction, however in recent years this has been undertake by Mt Rex Shipping under contract. At present, there is no proposal to change this arrangement.

Proposal

Both companies are seeking to renew the existing consents for the same volume (700,000m3/year), with the same monitoring conditions. The consent term sought will be 35 years. This is based on 20 years of consistent monitoring data concluding that sand extraction operation has not caused, and is unlikely to cause any adverse effects on the environment.

The existing extraction area will also be reduced in size. This was voluntarily offered earlier in the year as part of the outcome of Plan Change 102, where part of the extraction area was scheduled as a Site of Significance to Mana Whenua.

Next Steps

The consent applications aim to be lodged in late November 2025, and public notification will be requested.

Two Open Days at Mt Rex Shipping’s Helensville site have been proposed for - Thursday, 6 November and Saturday 8 November. This will give the public an opportunity to come to discuss the consents, to be provided with an overview of the sand dredging operation and a NIWA expert will also be present to answer any questions regarding coastal geomorphology and seabed ecology.

For further background information, you can find the latest NIWA monitoring reports here.