Melbourne

DURING the financial crisis, Rio Tinto Group needed cash and tried to unload its oldest mining business - one that began in 1872 hauling borates salts by mule from Death Valley to make US laundry soap. The company gave up on a sale because no one would pay the asking price. A decade later, the business is poised to be one of Rio's most promising.

That's partly because a borates deposit Rio discovered in the hills of Serbia contains a huge amount of another mineral that is becoming a hot commodity for the 21st century - lithium - used to make batteries that run electric cars and all sorts of mobile devices. London-based Rio, already a major producer of coal, aluminum, iron ore and copper, says the Jadar project could supply about 10 per cent of global demand for the metal.