Issue link: https://viewer.e-digitaleditions.com/i/142338
industryfocus DAZZLING PROSPECTS Starting a gold mine can be a slow ride to success or old age … and no one gets rich quickly. WORDS: JEREMY CHUNN Looking at the odds of success, you'd have to wonder if gold miners are crazy. As the price of the yellow metal oscillates at the whim of the always anxious financial markets, explorers play a dangerous game, spending huge amounts of other people's money to look for something that might not be there. First of all, you have to have some idea of where gold might be. In prospectors' jargon, these areas of interest are called 'provinces' – and they aren't obvious. The gold rushes of the mid-1800s came about when gold provinces apparent at the surface attracted a mad scramble of speculators, who toiled away with pans and pickaxes to effectively pluck money straight from the earth. What was found at the surface was often used as a guide to sinking a shaft and finding larger mineral deposits beneath. "It was a herd mentality. Once someone had a strike, that got telegraphed almost globally, and that created the gold rush," says Emmerson Resources managing director and CEO Rob Bills. "All the easy stuff at the surface in Australia has pretty much been found." Today's gold prospectors fall broadly into two categories: those who use past finds in known provinces as clues to still-hidden deposits; and those who seek new provinces. Singapore-based billionaire Robert Friedland is an example of a gold explorer who pursues deposits in provinces that some believe may have been mined out. His former company, Ivanhoe Mines, which operates in Australia and Canada, found what may be the biggest gold and copper deposit in the world: Oyu Tolgoi in Mongolia. (Where there's copper, there's usually gold.) Emmerson Resources is applying the same logic in the Tennant Creek mineral field, an area of about 4,000 square kilometres which produced up to 225,000 ounces of gold a year in the 1970s. The big mines from those days – Warrego, Peko, Juno, Gecko, White Devil, Nobles Nob – are now just huge holes in the ground. But Bills reckons the biggest deposit hasn't been found yet. Gold exploration techniques are sophisticated and expensive. A method Emmerson has used involves a helicopter fitted with an electromagnetic loop that can sense conduction underground that is associated with sulphides in copper. Another method involves analysing surface soil for traces of gold mineralisation carried in groundwater. The trick then becomes figuring out how far the water has travelled from the gold deposit. "If you have a number of independent data or methods that all tell you the same thing," Bills says, "then there's a high chance that when you drill your hole, that will be what you think it is." When a specific drill target – known to miners as an 'anomaly' – is identified, it's time to call in the drill rigs to take core samples, which are then 'assayed', or pulverised into a fine powder, and tested for their mineral content. 15