THE HINDU,23 OCT 2013
Australian scientists have literally struck gold.Researchers from Perth have found tiny particles of gold hidden in eucalyptus trees, in a discovery which could help future prospectors to find deposits of the precious metal.Commonwealth Scientific and Industrial Research Organisation (CSIRO) researchers said that they believe that the trees, sitting on top of gold deposits buried deep underground, suck up the gold in their search for moisture during droughts, Australian Broadcasting Corporation reported.“We weren’t expecting this at all. To actually see the gold particles in the leaves was quite an eureka moment for us,” said Melvyn Lintern, a geochemist at CSIRO.“The particular trees that we did the research on appear to be bringing up gold from a remarkable 30 metres depth, which is about the equivalent of a 10-storey building,” he said.The gold was found in the resource-rich Kalgoorlie region of Western Australia, site of a major gold rush in the late 1800s.The scientists used CSIRO’s Maia detector at Australian Synchrotron in Melbourne for X-ray imaging to analyse extremely small particles at high resolution and found that the gold particles with diameter one-fifth of a human hair.“The eucalyptus acts as a hydraulic pump — its roots extend tens of metres into the ground and draw up water containing the gold,” Lintern said.“As the gold is likely to be toxic to the plant, it’s moved to the leaves and branches where it can be released or shed to the ground.”Lintern, however, said even 500 trees growing over a gold deposit would only yield enough gold for a wedding ring.But scientists could use a technique known as “biogeochemical sampling” to give an indication of the presence of gold beneath the surface.“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,” Lintern said.“It’s a more targeted way of searching for minerals that reduces costs and impact on the environment.”He said the method could also be used to find other metals such as zinc and copper.The researchers 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,” Lintern said.New discoveries of gold have fallen by 45 per cent in the past decade, while prices have skyrocketed as reserves steadily dwindle — the cost of the yellow metal shot up by 482 per cent between December 2000 and March this year.
In 2011, the US Geological Survey estimated there were 51,000 tonnes of gold left in reserve in the world.
