New research from the CSIRO has uncovered the role ants and termites will play in discovering new gold deposits.
Research in science journals PLoS ONE and Geochemistry: Exploration, Environment, Analysis has found at test sites in the WA Goldfields that termite mounds contained high concentrations of gold, indicating larger deposits 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,” Aaron Stewart, a CSIRO entomologist, said.
He explained that “the insects bring up small particles that contain gold from the deposit’s fingerprint, or halo, and effectively stockpile it in their mounds.
“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.”
The CSIRO added that insects can provide a new, cost effective way to explore for undiscovered mineral deposits.
In Africa, ancient African civilisations used termites and their enormous mounds as a starting place for prospecting and uncovering deposits.
As termites continually search for water they can often dig down to depths of more than 70 metres and distances of hundreds of metres.
"Termites are nature's little drillers," researcher and University of Adelaide geoscientist Anna Petts explained at the Geological Society of Australia's Earth Science Showcase.
"Termites conveniently bring subterranean soil samples to ground level to construct or fix their mounds.
"So by simply taking a sample of a termite mound, geologists can gain a good idea as to what minerals and metals can be found in the ground beneath it – making it a much cheaper way to undertake preliminary soil testing for minerals exploration," she said.
"More intensive testing can then be undertaken if a site looks promising."
This method was used to find the Vila Manica copper deposit in Mozambique in 1973, while the massive Jwaneng diamond mine was also reportedly found by termite mound sampling.
A DeBeers geologist is believed to have found a piece of ilmenite – a classic diamond indicator – in a termite mound, which lead to further exploration and the discovery of Jwaneng.
The CSIRO's Dr. Ravinder Anand explained that "we can often dissect [the mound's] material and we can send it to the lab for processing and it can provide the clues for mineral deposits that are hidden under sediment".
It has already worked with entomologists to study how this process can be used, Anand adding that it has also studied the termites themselves, to see the concentration of metals in the insects.
Stewart stated that “We’ve found that metals accumulate in excretory systems of termites,” he said.
“Although the insects don’t 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 the redistribution of metals in the surface layer of earth.”
Tanami Gold also looked to termite mounds to provide geological information for their projects.
"It really has been a case of assessing whether termites in Australia work in the same way [as in Africa] – that is where our research has come into play and it has proved to be the case."
Geozoology and geobotany – testing metal concentrations in plants, have been used in mining for centuries.