The West Coast Ironsands
The North Island’s west coast is a unique marine ecosystem, with a shoreline of distinctive purple and black sand. The black matter is Titanomagnetite. It features a (so far unrecoverable) titanium component, along with an iron component. As well as being present on the shoreline, sand dunes and coastal hinterland, there is an even greater amount in the seabed
It was formed by the nearby volcanic cones of Taranaki, Pirongia and Karioi, which over the millennia, eroded vast quantities of black, iron-rich sand, down the streams and rivers on their flanks. Ocean currents then moved the sand north and southwards away from its source. The result is a series of deposits along 480 km of coastline from Whanganui to the Kaipara Harbour, and in nearly 20,000 km2 of the adjacent seabed. Many such deposits around the globe have been studied as potential sources of iron ore, but few are of commercial value.
The seabed resource
While the land based deposits are significant (see appendix), the amount of iron sand in the seabed is far larger in scale. This has been described as New Zealand’s biggest mineral resource. It’s potential extent is difficult to quantify, as concentrations vary and insufficient research has been made public from across the extent of this sea area.
As a reference, TTR have indicated a resource of 4 billion tonnes of concentrate in their various permitted areas. It lies in layers up to 30 metres deep, in varying concentrations, from Whanganui all the way to the Kaipara Harbour.
Current seabed mining proposals
Currently the entire sea area from Whanganui to the Pandora Banks near Cape Reinga, out to the 12 mile zone, is covered by either prospecting or exploration permits. Other permits extend from the 12 mile zone to the edge of the EEZ. These permits are held by a wide range of corporate entities, ranging from shelf companies to multinationals. Their primary target is titanomagnetite, though their permits are not restricted to this mineral.
The company with the most highly developed proposals is Trans-Tasman Resources, who have been prospecting intensively for the last few years. They have indicated in a series of bullish media releases, and through announcements on their website, that they are expecting to apply for resource consent to mine the inshore waters in the Patea area, by the end of this year (2012).
They have indicated a resource in the southern permitted area, that is recoverable at a rate of 30-50 million tonnes per year. The permits they apply for, if granted often apply for 35 or 40 years. At a recovery rate of 1/10, this means in excess of 300 million tonnes of sand being disturbed annually. The scale of this is difficult to fathom.
In the absence of any overarching management plan for this coastline, it would be natural to also expect that other permit holders will follow in the wake of this first application over time, so we view the first few cases as of utmost importance. Precedents set in these cases will have long lasting implications for the integrity of the west coast.