杏吧原创

IT鈥橲 a grey winter鈥檚 day on Sydney Harbour. Ferry passengers making their way from beachside suburbs to the city are shivering in overcoats and scarves, but for Phil Schmidt of CSIRO, Australia鈥檚 national research organisation, the weather is perfect. 鈥淚t鈥檚 not windy. That was the main thing we were concerned about,鈥� he says.

Schmidt is standing on a research vessel rolling against the swell between the North and South Head 鈥� the two outcrops of land that form the entrance to the harbour. The mild winds mean that it鈥檚 safe to winch his prototype 20 metres down to the seabed. This simple yellow box of sensors, called OceanMag, could soon be helping companies discover vast new reserves of oil and gas in shallow waters (see Graphic).

Most of Australia鈥檚 remaining hydrocarbon deposits are thought to be in seas less than 500 metres deep, but these regions are more difficult to explore than might be expected. One method that geologists rely on to find oil is to bounce electromagnetic pulses off the rock layers under the seabed. This helps them distinguish between deep reservoirs that contain useless saltwater and those packed with oil, but the technique often fails in shallow seas because waves and currents can disrupt the signal. Schmidt鈥檚 prototype is unique because it can filter out this unwanted noise.

OceanMag is just one of a host of new Australian technologies offering smarter ways to identify places to dig or drill. The research is being driven by a resources boom in the country, which is making millionaires by the day. As a rough rule of thumb: if you can burn it or build with it, Australia is rich in it. The land is packed with coal, iron, uranium, natural gas and other geological goodies that countries such as China and India are only too keen to get their hands on (see 鈥淏oom by numbers鈥�).

Unsurprisingly, companies have been seeking to turn these raw materials into record profits. And for geologists, engineers and other specialists in the sector, pay and career opportunities have never been so good. A serious skills shortage has even triggered calls for changes to immigration law to make it easier to bring in workers from overseas to fill the gap (see 鈥淭imes of plenty鈥�).

In the long term, Australia鈥檚 resources boom cannot be sustained with known deposits. 鈥淩ight now the mining industry is living off new discoveries near existing operations,鈥� says Brent McInnes, who heads CSIRO Mining and Exploration鈥檚 discovery technology team, which was set up in 2004. 鈥淭he problem is that there are real deficits in commodities such as nickel, zinc and copper, and these need to be replaced with new greenfield mines.鈥�

To achieve this, companies and researchers are focusing on three areas: improving their understanding of how ore bodies and petroleum deposits are formed; refining the techniques they use to seek out hidden ores and oil; and gaining the expertise needed to exploit far-flung and inaccessible regions.

To better understand how a region of rock forms and deforms through time, McInnes鈥檚 discovery technology team has developed Alphacron, a technology that charts temperature changes in any given rock formation over millions of years. This gives clues to the likely size and location of an ore body. Minerals such as copper, or rocks that bear diamonds, such as kimberlite, are often associated with magma plumes. Alphacron can tell geologists when magmas intruded near to the rock formation, even if there is no other evidence of intrusion. It can also tell whether these magmas came from deep in the Earth or from closer to the crust.

The technology itself is simple: it works by blasting mineral samples with a laser and then analysing the gas that is given off. Apatite and zircon contain helium when they form, but over geological time they release the gas if subjected to higher temperatures. A low level of helium suggests that a magma body intruded nearby during a rock formation鈥檚 history. The researchers have sold prototypes of Alphacron to research groups in China and the US.

Refining and defining

Meanwhile, companies are refining the techniques they use to seek out hidden ores and oil. Exploration geologists have long used fluctuations in Earth鈥檚 gravitational field to see beneath the subsurface. Placing ground sensors across a region enables them to spot buried deposits of minerals, which show up as specific gravity anomalies (see Graphic). Melbourne resources company BHP Billiton has developed technology that can detect these anomalies from a single device on board a plane, which means it can search for mineral and hydrocarbons deposits across large and often inaccessible regions. The technology, Falcon, is already showing its potential. It has been used to identify iron formations and diamond pipes in Western Australia, and in South Africa it has identified 21 sites for future diamond exploration. In order to continue the resources boom once known deposits have been exploited, the mining industry needs to move on to far-flung and inaccessible regions.

One company taking this idea to its extreme 鈥� and digging where no one has dug before 鈥� is Sydney-based Nautilus Minerals. Earlier this year, the company sampled and drilled an area off the coast of Papua New Guinea in ocean depths of 1600 metres, and recovered samples from extinct hydrothermal vents and chimneys containing gold, copper and silver (New 杏吧原创, 17 December 2005, p 40). It now owns licences to explore 15,000 square kilometres of seabed in the region.

Seabed mining is where technology such as OceanMag could come into its own. As well as searching for petroleum, the device could also be used to help spot extinct black smokers and so find the minerals associated with them. At these sites, the process of mineral formation demagnetises surrounding basalt, which can be spotted with electromagnetic pulses. 鈥淪o in principle, you could stick something like OceanMag down there and find these sites,鈥� says Schmidt.

The wealth of untapped resources on Australia鈥檚 seabed may have been underestimated. McInnes鈥檚 discovery technology team, along with Geoscience Australia and the CSIRO research project Wealth from Oceans Flagship, has spent the past year assessing the mineral potential of Australia鈥檚 exclusive economic zone, where the country holds rights over exploration off its coast. The zone, which covers 8.15 million square kilometres, is the world鈥檚 third largest such zone after those of the US and France. This week, the researchers plan to release a map detailing their findings, showing among other things new evidence of diamond deposits off Australia鈥檚 north-west shelf. 鈥淲e have [found] a 30-fold increase in the number of prospective mineral sites on the sea floor in Australia,鈥� says McInnes.

He adds, however, that 鈥渢his is a mineral potential map, not X marks the mine. We鈥檒l need more surveys to work out exactly what鈥檚 there.鈥� And even if you do know the exact location of the buried treasure, the engineering challenges of sea-floor mining remain huge. 鈥淚 don鈥檛 know how you鈥檇 go about mining a diamond pipe in 100 metres of water. Maybe somebody will some day.鈥� But for now, he says, 鈥渨e are pushing at the frontiers of chemistry and physics 鈥� we鈥檙e really pushing the limits of technology.鈥�

聯The engineering challenges of sea-floor mining remain huge聰

All this is good news for researchers across the mining and exploration sector, who until now have struggled to get funding. 鈥淢any companies would still rather buy something that is proven and works, rather than pay for development,鈥� says Schmidt.

However, the future looks promising, says Mike Hood, chief executive officer of CRCMining, the cooperative research centre for mining in Queensland, which has recently developed a way of improving safety in coal mines by draining explosive methane from coal seams using water jets, known as tight radius drilling (see Graphic). 鈥淢ore money is being spent on research now than five years ago. What鈥檚 more, reorganisations in companies such as Rio Tinto suggest they鈥檙e going to commit to an even more technological future. I think in a few years there will be more and bigger projects to come.鈥�