Commonwealth Scientific and Industrial Research Organisation (CSIRO) scientists in Australia have discovered that eucalyptus leaves are sometimes laced with tiny grains of gold. The roots of the eucalyptus trees (or Australian Gum trees) extend deep into the ground, sometimes as much as 50 meters down, where gold deposits get drawn up through their roots to wind up in their leaves. The amount of gold per tree might be small, but spotting gold in their leaves gives miners a good idea where to find rich veins of gold. They just might turn out to be a gold miner’s best friend.
Eucalyptus leaves aren’t just for koalas anymore — they’re also for miners.
Eucalyptus leaves are often thought of as just food for koalas, or as an ingredient in cough drops. However, now that traces of gold have been found in eucalyptus leaves by scientists from CSIRO, Australia’s main science agency, trees which have the most gold in their leaves could becomes an important sign to miners of rich sources of gold.
Using eucalyptus leaves as an indicator of these deposits of gold could prove to be an environmentally friendly and cost-effective method to locate gold which wouldn’t require the use of a drill.
It’s theorized that the gold the eucalyptus trees draw up is toxic to them, and that the most efficient way for the trees to rid themselves of the gold is to deposit it in their leaves and possibly their bark. The eucalyptus trees can get rid of the gold in this manner before it builds up to potentially dangerous levels and threatens their lives.
The tiny grains of gold in the eucalyptus leaves are only around a fifth of the diameter of a hair from your head, and they are not visible to your eyes. They were detected by using x-ray elemental imaging.
There is so little gold in the eucalyptus leaves that it would take all of the gold from the leaves of approximately 500 eucalyptus trees to have enough to equal the amount of gold in “a wedding ring,” according to Mel Lintern, a CSIRO geochemist.
Lintern said that finding gold in eucalyptus leaves marks “the first time that anyone has seen gold in any biological tissue.”
Specifically, the trees that the researchers examined for gold in their leaves were acacia and eucalyptus ones in Western Australia, and from one location in the south of the continent. Still, Dr. Lintern stated that, if the conditions are right, all types of eucalyptus trees would behave the same way.
Over the past decade, new discoveries of gold have dropped by 45 percent, so this new method of locating gold deposits could eventually be a huge benefit to miners.
According to a press summary, the “link between” plant growth like eucalyptus leaves and “buried gold deposits” could lead to “developing new technologies for mineral exploration.”
The research that the CSIRO scientists did was published on Wednesday in Nature Communications.
While there is not enough gold in eucalyptus leaves to retire on, CSIRO scientists, by discovering gold in the leaves, have also found a potentially useful tool for miners of this precious metal to locate underground deposits of gold more economically and in a manner that’s more friendly to the environment.
Written by: Douglas Cobb