Geoscientists from Australia have discovered gold particles in the leaves, twigs and bark of eucalyptus trees, claiming a “eureka” moment which could revolutionise gold mining. The particles are much too small to be seen with the naked eye but have been detected using a type of x-ray that is especially good at picking up trace amounts of metals and minerals.
The research group used the CSIRO’s Maia detector for x-ray elemental imaging at the Australian Synchrotron in Melbourne to analyse extremely small particles at high resolution. The portions of gold are about one-fifth the diameter of a human hair.According to the researches even 500 trees growing over a gold deposit would only yield enough gold for a wedding ring.
The paper says that eucalyptus and acacia trees, such as the ones studied at the Freddo and Barns Gold prospects in Western and South Australia respectively, have deep and extensive root systems. In times of drought, their roots dig deep in search of water. So deep, in fact, that some trees have literally struck gold.
The scientists have known from their laboratory experiments that trees have the ability to absorb gold but this is the first time they have proved that it is actually happening in nature.
The findings, which were published this week in the online journal Nature Communications, show how biogeochemical absorption of gold is possible. This, according to the researchers, could lead to new and more successful prospecting methods.
Dr. Mel Lintern, a geochemist from Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO), said: “We’ve found a lot of the easy deposits in Australia and elsewhere in the world as well.
“Now we are trying to tackle finding these more difficult ones that are buried beneath tens of metres of river sediments and sand dunes. And the trees are providing us with a method to be able to do this.”
The researchers said they have also found gold in the leaves of other trees, such as the Acacia mulga.
“We’ve actually found gold not only in trees but in shrubs that are growing beneath the trees as well, so (it is) not restricted to any particular trees at all,” Dr Lintern said.
The real value of the study is that nature’s own version of gold leaf could provide mine companies with an inexpensive and environmentally friendly indicator of where to drill test sites, reports the Daily Mail.
“The leaves could be used in combination with other tools as a more cost-effective and environmentally-friendly exploration technique,” Lintern said.
“By sampling and analysing vegetation for traces of minerals, we may get an idea of what’s happening below the surface without the need to drill. It’s a more targeted way of searching for minerals that reduces costs and impact on the environment.
“Eucalyptus trees are so common that this technique could be widely applied across Australia. It could also be used to find other metals such as zinc and copper.”
The study by the Commonwealth Scientific and Industrial Research Organisation in Western Australia showed levels of the precious metal were highest in trees growing directly over gold seams, one of which was 115 feet down.