English researchers at the University of Exeter have developed a new, inexpensive method to uncover copper deposits.
Dr Ben Williamson, of the university’s Camborne School of Mines, and Dr Richard Herrington from the London Natural History Museum, worked together to develop the new technique, which they say could become a very cost-effective way of discovering porphyry-type copper deposits.
These kinds of deposits provide around 75% of the world’s copper and a significant amount of molybdenum and gold. Porphyry-type copper deposits, which originally form at several kilometres depth below the Earth’s surface, above large magma chambers, are relatively rare, particularly the largest ones, which make sense to mine. In addition, most near-surface deposits have already been discovered.
The project, funded by Anglo American, compared the chemical compositions of minerals from magmatic rocks that host porphyry deposits against those which are barren.
That is why any new method to locate deeper deposits is of great interest to the mining industry.
The project, funded by Anglo American (LON:AAL), compared the chemical compositions of minerals from magmatic rocks that host porphyry deposits against those which are barren.
A case study was then undertaken of a major new porphyry discovery in Chile, to test their theory.
The trial unveiled that the magma chamber below the porphyry undergoes discrete injections of water-rich melts or watery fluids, which improve its ability to transfer copper and other metals upwards to form a copper deposit.
“This new method will add to the range of tools available to exploration companies to discover new porphyry copper deposits,” Williamson said. “Our findings also provide important insights into why some magmas are more likely to produce porphyry copper deposits than others.”