Sun, Dec 08, 2013 - Page 14 News List

New technologies unearth minerals under deep cover

By Clara Ferreira-marques  /  Reuters, LONDON

Analysis of so-called “roo poo” may give insights into the minerals that are contained in the plants that kangaroos have fed on and are then concentrated in the animal itself.

For example, Superconducting Quantum Interference Devices are sensitive magnetic sensors that can detect deep, magnetic sulphide ore bodies and distinguish them from other conductive material, like rock. Versions of the technology have already been put to use by companies like mining giant Anglo American PLC in exploration in Finland under sediment deposited by glacial ice, contributing to a significant find.

Similarly, the Las Cruces copper deposit in Spain, now part of First Quantum Minerals Ltd, was discovered through anomalies in gravity measurements that led the exploration team past where the Iberian pyrite belt — which crosses Portugal and Spain — was thought to end.

Furthermore, the British Geological Survey is using small aircraft to gather magnetic and radiometric measurements across the southwest of England, including Cornwall and Devon, where tin, copper and other metals were mined for centuries.

“This survey will give us a pretty good idea of how much modern technology will reveal, over and above what is already known, in a pretty intensively studied area,” Neill Wood of the Camborne School of Mines at the University of Exeter said.

A large part will be not just about identifying deposits and increasing the ability to “see” underground, but about being able to drill at reasonable cost. Drilling a deposit 2.5km below the surface can, depending on the contract and location, cost US$500 per meter — an almost prohibitive charge.

Australia’s Deep Exploration Technologies Cooperative Research Centre, a government and industry-backed effort to cut that cost and speed up deep drilling, has worked on prototypes including a coiled tubing rig.

This uses a reel of tubing and eliminates the manual handling of drill rods — which is costly and dangerous — and it has a motor at the bottom of the hole, cutting fuel costs.

Research there also aims to help teams analyze findings immediately rather than having to extract meters of core, or sample tubes of rock pulled out and sent off-site for tests.

“Hopefully this can mean a quantum change in the way we explore at depth,” center chief executive Richard Hillis said. “You’ll have several shots at finding the needle in the haystack and try and move towards it, rather than one shot.”

For the industry’s major players, the appeal is an ability to combine approaches: deeper exploration and better visibility in covered areas, but also traditional methods in existing regions.

“In Chile, for example, there have been quite a lot of recent discoveries in old mining districts. Some of these areas that are considered mature and well-explored,” said Tracey Kerr, head of exploration at Anglo American. “I think you have to be a little more open-minded about the potential.”

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