Back to the future to uncover hidden riches

By Emily Lehmann

LECODE modelling

Iron rich material in the deposit: The orange showing areas with the highest percentage of iron.

We’ve created our very own time machine – a new modelling tool that can simulate millions of years of landscape evolution and possibly reveal hidden treasures.

Using the tool called LECODE, and iVEC’s supercomputer, our scientists travelled back in time to pinpoint the exact moment when deposits formed in the iron-rich Hamersley province in Western Australia.

The study has revealed potential locations for hidden and unexplored iron ore deposits.

“We simulated how erosion and water flow influenced the transport of sediment over thousands to millions of years, showing how the iron-rich soils were carried from one place to another to build sedimentary deposits,” says researcher Dr Guillaume Duclaux.

“Sedimentary (aka alluvial) deposits at the Earth’s surface can host significant mineral resources, however exploring them is challenging because they are built from layers of transported material that effectively hide the mineral deposits within,” he says.

“By exploring the material’s movement from the hill slopes to the valleys, we can predict the location of larger deposits hosted underground.”

There’s a high economic value attached to sedimentary iron deposits, which provide 40 per cent of Australia’s iron ore exports.

“Geologists and explorers could use the tool to make new mineral discoveries and it will reduce exploration costs and the environmental impacts associated with traditional drilling techniques,” Dr Duclaux says.

“This research has brought up new questions around the processes that trigger the formation of this type of deposit, which we’re investigating next,” he says.

These graphs shows the accumulation of iron-rich material in sedimentary deposits.

The accumulation of iron-rich (Fe) material in the deposit.

Our tool is a 3D modelling code tailored to solve problems related to basin and landscape evolution. It could also be applied to other resources, such as gold and petroleum.

Dr Duclaux, Dr Tristan Salles and Dr Erick Ramanaidou presented this work at the AusIMM Iron Ore 2013 conference last week.

Learn more about CSIRO’s research in mineral exploration.


Termites strike gold

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Giant Northern or Mastotermes darwiniensis worker termites.

Ant and termite nests could lead to hidden treasure according to research conducted by CSIRO.

Research published in science journals PLoS ONE and Geochemistry: Exploration, Environment, Analysis, found that at a test site in the West Australian goldfields termite mounds contained high concentrations of gold. This gold indicates there is a larger deposit underneath.

“We’re using insects to help find new gold and other mineral deposits. These resources are becoming increasingly hard to find because much of the Australian landscape is covered by a layer of eroded material that masks what’s going on deeper underground,” Dr Aaron Stewart, CSIRO entomologist said.

Termites and ants burrow into this layer of material where a fingerprint of the underlying gold deposit is found, and bring traces of this fingerprint to the surface.

“The insects bring up small particles that contain gold from the deposit’s fingerprint, or halo, and effectively stockpile it in their mounds,” Dr Stewart said.

“Our recent research has shown that small ant and termite mounds that may not look like much on the surface, are just as valuable in finding gold as the large African mounds are that stand several metres tall.”

Mineral resources make up $86.7 billion of Australia’s exports and new discoveries in many commodities are required to sustain production. After 150 years of mining, gold and other mineral deposits near the surface have been discovered and miners need new tools to explore deeper underground.

Insects could provide a new, cost effective and environmentally friendly way of exploring for new mineral deposits, avoiding the traditional method of expensive and often inaccurate drilling.

Dr Stewart’s work has also found that insects carry metals in their bodies.

“We’ve found that metals accumulate in excretory systems of termites,” he said.

“Although the insects may not concentrate metals in their bodies, they actively rid their bodies of excess metals. This process shows up as little stones, much like kidney stones in people. This finding is important because these excretions are a driving force in redistribution of metals near the surface.”

Dr Stewart was selected as a finalist in this year’s Fresh Science Awards.

Media: Liz Greenbank. Mb: 0408 778 189. E: liz.greenbank@csiro.au


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