CLOUD

The world-first technology developed by the Co-operative Research Centre for Predictive Mineral Discovery (pmdCRC) enables mineral explorers to predict where buried gold deposits are most likely to occur - even when there isn't a trace detectable at the surface. At the heart of the team's advance are 3D computer visualisation and modelling tools that relate deformation in the rock to the flow of mineral fluids containing gold. This involves modelling the shapes and distortions of buried structures such as basalt 'domes' and then using the model to predict where fluids are most likely to flow and pond to produce the buried gold lodes. The technique has the potential to have a major and fundamental impact on gold exploration in difficult regions of Australia that are buried beneath a sandy shroud and also deeper within the earth's surface. This will open up new opportunities for exploration in Australia, says pmdCRC Chief Executive Dr Bob Haydon. "Over the past 150 years we've found just about all the 'easy gold' that is detectable at the surface. In modern times, explorers have been unable to explore effectively under this blanket of cover because of their inability to 'lift the blanket'. Just how do you find a gold deposit that leaves no surface trace of its existence, and is buried under hundreds of metres of soil, sand and silt?" Dr Haydon says that recent new gold discoveries in Victoria's "Golden Triangle" have established the credentials of a technique which has been dreamed of by mineral explorers for decades - predictive mineral discovery, the ability to foretell where rich deposits are most likely to occur using scientific models. "It also opens the way for large savings in exploration by reducing the number of drill-holes needed to find gold mineralisation. This offers the Australian gold industry an important technical edge in a hotly competitive world gold market. "In an industry where money - and lots of it - is literally poured into the ground in the quest for new mineral deposits, explorers need a way to remove the uncertainty about where to drill. "There is no crystal ball - just smart science from the Predictive Mineral Discovery CRC." Working with partners MPI Mines in Victoria's Goldfields, CRC researchers used detailed drilling and geophysical information from the well-understood orebody at the Stawell Gold Mine to construct an accurate 3-dimensional model of its subterranean basalt dome. The team then ran numerical simulations of fluid flow and deformation to determine where areas of high fluid flow and high shear-strain in the rock coincided. Drilling then found these areas contain high grade gold deposits. "This was a resounding confirmation of our theory that the gold was concentrated by the interaction of these two factors," says Dr Haydon. Impressed at this initial success, MPI Mines then used the predictive model in their regional exploration program to help define drilling targets in already identified prospect areas. The company began diamond drilling of targets identified using CRC technology - and have already discovered significant gold mineralisation. MPI Mines Managing Director, Brian Phillips, announced in a recent briefing to the Australian Stock Exchange: "We are very encouraged by the results from the program so far. The Stawell Corridor has only been lightly drilled but the first two targets we defined have potential gold systems similar to the Stawell orebodies". Dr Haydon explains "One of the two new gold zones discovered, the Wildwood Prospect, had been explored previously using a systematic, but unfocused, near-surface drilling pattern - with limited success. Without our new predictive tools, this new discovery may not have been made at all, as the company would have probably wound back its exploration of the area, as have previous explorers, because of the lack of success." "The minerals and energy sector is Australia's largest export earner, expected to bring in around $58 billion in 2004-05. Exploration is a key link in the metals supply chain. Unless our resources are continually replenished through successful exploration and discovery, the wealth generated for Australia by the mining sector will decline in the longer term. "This project is clearly an example of the development of frontier technologies that have the capacity to transform and build Australian industry and as such aligns perfectly with one of Australia's national research priorities." The techniques and tools developed in this project are being transferred to the Australian mineral exploration industry to assist explorers prioritise and focus their exploration activities.