Rare earth minerals could be common
Astepped-up search for rare earth elements in New Zealand found more than 20 locations where the valuable minerals might be found.
Almost all are in the West Coast and Fiordland but Stewart Island, Canterbury, NelsonMarlborough, and Kerikeri in Northland also feature.
Rare earth elements or minerals have many uses in modern society, including electric vehicles, wind turbines, aerospace components, consumer electronics, steel and glass additives, sonar systems, batteries, and ceramics.
They are sometimes labelled ‘‘green minerals’’ or ‘‘clean-tech’’ minerals to contrast them with coal and other dirty, mined resources.
There are 17 rare earth elements, depending on the definition, and each has a place on the periodic table.
The new report by GNS Science and New Zealand Petroleum & Minerals used mostly existing knowledge to map the country’s rare earth ‘‘mineral potential’’.
‘‘If economic deposits of ‘clean-tech’ minerals are found here, we have the potential to provide high-quality, ethically and sustainably derived metals that will fetch a premium on world markets,’’ concluded GNS in its annual report.
However, ‘‘more data is needed to realise the potential of this endowment’’, it said.
Rare earth elements are not hugely rare. Granite benchtops in many homes contain traces amounts, said Dr Rose Turnbull, a petrological scientist at GNS.
The rock types that are known to host rare earth elements elsewhere in the world are present in New Zealand, Turnbull and four co-authors wrote in the science paper.
‘‘Yet New Zealand remains under-explored for [rare earth elements] relative to other countries, with only very limited, historic efforts’’ to find them, they wrote.
The new maps point to where further work is likely to be most rewarding.
Rare earths are known to occur in ‘‘carbonatite rocks’’ and ‘‘alkaline intrusions’’.
They are magma chambers that rose towards the surface 40 million to 80 million years ago. They didn’t quite reach the surface, instead, numerous complex and rare processes occurred that concentrated the rare earth elements as the magma cooled and solidified underground.
Tectonic action and erosion then brought the deposits closer to surface. In some cases, the deposits were further eroded and swept downstream to beaches.
The methodology to produce the maps – described as ‘‘first of its kind in the world’’ – must be further improved with ground truthing and probably drilling.
Based on rare earth content of soils, the authors suggest the best place to look harder is inland from Hokitika and Greymouth. The igneous complexes at Tapuaenuku in Marlborough and Mandamus, south of Hanmer Springs, were also promising.
Aspiring Resources, a company apparently owned by businessman Duncan Hardie, got a Minerals Prospecting Permit for Mandamus earlier this year and lists rare earth elements as one of its prospecting interests.
It’s not GNS’ job to make policy decisions on whether to allow a mine, the paper said. Turnbull estimated there’s probably 10-20 years of work needed before a commercial mine could open.
China dominates the supply of rare earth elements. It has about 37 per cent of global reserves but supplied 78 per cent of America’s imports.
President Donald Trump did not include them in the trade war with China, Bloomberg reported in September.
Last December, US Interior Secretary Ryan Zinke said the US was ‘‘vulnerable’’ because it relied so heavily on Chinese supplies of rare earth.
We have the potential to provide high-quality, ethically and sustainably derived metals.