Lynn Olssen, Rio tinto's general manager of exploration, said on Thursday that the company had changed its exploration strategy to consider small deposits with growth potential as the likelihood of finding large, low-cost mines declined.

Global mining giants such as Rio tinto and BHP billiton have long hoped to find big deposits. Because large deposits, known as "primary" deposits, have economies of scale and can withstand the commodity price cycle.

Green technology is now in high demand for copper, whether for wind turbines or electric cars. But Lynn Olssen said: "copper deposits are hard to find, so companies have to adopt new exploration strategies." "Copper was our first choice," Olssen told a mining conference in Melbourne. Like BHP, we want tier one copper, big and cheap. * the good thing is that the mine is not deep, near the coast, and has some good infrastructure. However, * in recent years, it has been difficult to find such mines, so we changed our strategy."

Rio is now looking at smaller mines, she said. These mines need to be located in areas where political risk is low and wealth inequality is not high. With moderate capital expenditure, it can be developed in a reasonable period of time. Such resources are then considered to have potential for growth.

Olssen's views echo those of Rio tinto chief executive jean-sebastien Jacques in London this week. Large miners need flexibility in choosing exploration projects, Jacques said. As well as choosing large mines, miners should also aim for phased investment, starting with smaller mines. These mines can be developed and built quickly, safely and with potential for growth. Small projects also generate faster cash flow.

Rio spent $287m on mining exploration and assessment in the first half of the year, up 24 per cent from a year earlier, according to its semi-annual report. The miner is actively exploring for eight commodities in 17 countries.

Olssen says the company now has more greenfield projects than it has in 20 years. （From Alu)