Sand mining vs seabed mining

Katy Jones’ excellent article on sand mining was great - except she didn’t make a clear distinction between sand mining and seabed mining.

The fundamental difference between the two is that sand mining extracts the sand from the sea floor, taking it away, and seabed mining - usually for minerals - returns most of what is dug up back into the environment.

This is where you run into the potentially huge environmental issues that we are facing with the Trans Tasman Resources’ application to mine the South Taranaki Bight, where there is huge concern about the impact of displacing 45 million tonnes of the seabed a year, every year for 35 years.

After extracting the ironsand from the seabed material, the rest is returned to the environment but on the way to the sea floor a large portion of it will first be distributed throughout the water column, creating a ‘‘plume’’ which could have a massive and negative impact on everything in those waters - from phytoplankton to krill and the species that feed on them, all the way up to the blue whales now confirmed as resident in the Bight.

On the sea floor it will create dead zones. Yes, sand mining does affect the environment. In Pakari, it has changed the sand dunes and altered the coastline, but its impact is vastly different to seabed mining, which is for minerals including iron sand, ilmenite and phosphate. Cindy Baxter

Kiwis Against Seabed Mining, June 8