Glittering prize: Mineral riches believed discovered on Ruapehu Plateau

Roy Giddens’ incredible journey began with a eureka moment reminiscent of the 1960s TV show The Beverly Hillbillies.

Tararua hunter Giddens had been camping by a river in the remote North Island area of Retaruke and was stalking a stag with his hunting bow.

The clouds parted and he noticed the rocks of the river bed all around him glittering in the sun.

Giddens obtained a prospecting licence and collected surface samples, enlisting the help of overseas geologists who have detected traces of rare earths, platinum group elements and gold and silver.

The Erua-Ritaruki mineral field is on mainly forested Crown Land just west of the Tongariro National Park boundary and boasts an abundance of fossils – everything from tiny shells to sea turtle eggs and moa remains – plus fragments of volcanic “fumeroles”, about the size of a large circular bread loaf.

These ancient volcanic chimneys apparently bubbled to the surface as so-called “black smokers” when the Central North Island lay on the primordial ocean floor.

Giddens says they were a part of the volcanic activity which pushed valuable minerals and metals to the surface from deep within the earth.

Analysis has since confirmed metals including titanium, chromium, copper and a wide range of the kind of minerals used in green technology, such as electric car batteries, and wind turbines.

“There are so-called precious metals in abundance, but the rare earth elements are likely to generate the most interest,” Giddens says. “Worldwide these are in hot demand, with China controlling much of the market and many countries worrying about securing a reliable supply to fuel their economies.

“Rare earths are used in the production of everything from electric car batteries, to phones, computers to the magnets for wind turbines. You couldn’t work from home on your PC without them, because every computer has components containing rare earths.

“The Ruapehu district is sitting on the kind of mineral riches vital to sustain our modern world.”

Giddens may well be getting ahead of himself but the potential is exciting to consider.

Whether valuable metals and minerals are present in quantities to make commercial extraction viable will not be determined until exploration licence is granted. This would allow bores to be drilled to establish the depth of the estimated 24 square kilometre mineral field.

Samples sent for multi-element analysis to Genalysis Laboratory Services in Western Australia have confirmed rare earths present, while gold has been confirmed in samples sent to a university laboratory in China.

Timothy M. Kusky, a professor at the University of Geosciences in Wuhan, says only exploration could confirm commericial potential in the field.

“Roy has identified a prospect, that needs additional work for the geological mapping to investigate the mineral resources potential of the area,” Kusky says.

“Roy sent me some samples of some pyrite vein systems he collected there, and I had my team investigate the formation of the pyrite, and we found a small amount of gold in the system.”

Kusky says the samples may have originated on the far edge of a hydrothermal system.

“It is possible, but needs a real geologic study before anything more can be said. In the prospecting world; some dreams come true and some are just dreams. I have no data to evaluate which one is the case here,” he says.

He says that, if left in the ground, the metals and rare earth elements at Retaruke will simply erode into the river and be washed out to sea where they would be impossible to capture.

Giddens’ prospecting licence – which has now lapsed – identified the valuable minerals across an area of about 24 sq km. His company, Oryan Ltd, is seeking backing to gain an exploration licence, to measure the actual depth.

“On the surface particles of magnesium, titanium and iron are mixed up with rare earth elements in a sand that called monazite, while rock also contain rare earth elements. These minerals contain all the lanthanides as well as transition metals including the nobles [platinum group elements, including gold and silver among others].And it is thought that the minerals are likely to be present to a depth of 180m, or more.”

The deposit, part of the Taupo Volcanic Zone, is not the only one in the country, but Giddens sees it as particularly attractive for mining.

“This is Crown Land, that it is in an area with a relatively low population and close to rail infrastructure is a great advantage. Early indications are that it could be among the richest mineral fields on its type in the world. But only systematic prospecting to determine the depth of the field can quantify this,” he says.

“If this field runs as deep as we expect it to, it could be worth billions of dollars to our country.”

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