The Asia Miner

JUL-SEP 2019

The ASIA Miner - Reporting Important Issues to Mining Companies in the Asia Pacific Region

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the asia miner • volume 16 • issue 3 30 FEATURE: Gold Gold has fascinated the world since ancient ঞmes, treasured primarily as a trusted source of wealth, for use in jewellery, to many modern electronics. Today, we're sঞll learning about the yellow metal, such as how a gold deposit is formed and how it travels around the earth, so that we can come up with much-needed and clever new strategies to find and produce it. Geologists from Australia's naঞonal science agency, CSIRO, are revealing some of gold's secrets and coming up with innovaঞve ways to search for gold faster, in a more cost-effecঞve and environmentally safe ways. CSIRO discovered that trees in the Kalgoorlie region of Western Australia can draw up gold from the earth and deposit it in their leaves and that termites can harbour gold in their mounds. Now in the latest breakthrough, scienঞsts have discovered gold-coated fungi. This thread-like fungi lives in soils and zooming in on this organism reveals balls of gold aached to its strands. The gold gets there through an oxidisaঞon process. A surprising discovery given gold is so chemically inacঞve. The fungi dissolves and precipitates parঞcles of gold from their surroundings and then aaches it to their strands. There may be a biological advantage in doing so too, as the gold-coated fungi were found to grow larger and spread faster than those that don't interact with gold. They also play a central role in a biodiverse soil community, meaning the gold-coated fungi play host to a more diverse range of other fungi when compared to those that don't. This is the first evidence that fungi may play a role in the cycling of gold around the earth's surface. "Fungi can oxidise ঞny parঞcles of gold and precipitate it on their strands – this cycling process may contribute to how gold and other elements are distributed around the Earth's surface," CSIRO lead author Dr Tsing Bohu said. "Fungi are well-known for playing an essenঞal role in the degradaঞon and recycling of organic material, such as leaves and bark, as well as for the cycling of other metals, including aluminium, iron, manganese and calcium. "But gold is so chemically inacঞve that this interacঞon is both unusual and surprising – it had to be seen to be Australian scientists discover gold-coated fungi Gold-coated-fusarium-oxysporium-fungi believed." Dr Bohu is undertaking further analysis and modelling to understand why the fungi is interacঞng with gold, and whether or not, it's an indicaঞon of a larger deposit below the surface. Australia is the world's second largest gold producer, and while gold producঞon hit record peaks in 2018, forecasted esঞmates show that producঞon will decline in the near-future unless new gold deposits are found. New, low-impact exploraঞon tools are needed to make the next generaঞon of discoveries. CSIRO is using innovaঞve science and technology to solve the greatest challenges, like ensuring the world has a sustainable supply of resources. "The industry is acঞvely using innovaঞve exploraঞon sampling techniques, such as gum leaves and termite mounds, which can store ঞny traces of gold and can be linked to bigger deposits below the surface," CSIRO chief research scienঞst Dr Ravi Anand said. "We want to understand if the fungi we studied, known as fusarium oxsporum – and their funcঞonal genes – can be used in combinaঞon with these exploraঞon tools to help industry to target prospecঞve areas in a way that's less impacul and more cost-effecঞve than drilling." The researchers also highlight the potenঞal to use fungi as a bioremediaঞon tool to recover gold from waste. While Fusarium oxsporum is commonly found in soils around the world and produce a pink mycelium or 'flower' – it's not something prospectors should go foraging for, as the parঞcles of gold can only be seen under a microscope. The discovery was made possible thanks to collaboraঞon between CSIRO, the University of Western Australia, Murdoch University and Curঞn University. The research involved a mulঞ- disciplinary approach harnessing geology, molecular biology, informaঞcs analysis and astrobiology.

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