Massive ore deposits of copper, lead, zinc, silver, gold and other metals formed in this way.

ECONOMIST: Minerals

Instead, Rio struck a deal with BHP Billiton, its main competitor, to exploit jointly the vast iron-ore deposits of Western Australia's Pilbara region.

ECONOMIST: Not quite a love-in, but too important for a dust-up

Mrs Rinehart built her riches on an inheritance from her late father, Lang Hancock, a pioneer prospector of Western Australia's vast iron-ore deposits.

ECONOMIST: Fears grow for a newspaper group��s editorial independence

Instead, Rio struck a deal with BHP Billiton, its main competitor, to exploit jointly the vast iron ore deposits of Western Australia's Pilbara region.

ECONOMIST: Australia and China

Exploitation of the estimated two billion tonnes of iron ore deposits in Hajigak mine - located in Bamiyan - is expected to begin by 2015.

BBC: Indian consortium wins $10bn Afghanistan mines deal

This meets demands from Indian states that they should have the benefit of adding some value after their iron-ore deposits have been mined, while also allowing down-stream processes to be tailored to meet local requirements.

ECONOMIST: Why the Tata-Corus deal makes sense for both parties

Tata, which mines all the iron ore and coal it needs, now aims to carry out primary steel production close to its iron-ore deposits, and then ship semi-finished steel for finishing close to foreign consumer markets.

ECONOMIST: Why the Tata-Corus deal makes sense for both parties

Another challenge, Denbow said, is that when companies find higher ore-grade deposits, they are often far under the ground, making them more difficult and more dangerous to mine.

FORBES: USAGX's Denbow: Gold-Mining Companies Face Challenges Finding New Supply

South Korea's Yonhap news agency reported that the corporation hoped to exploit deposits of iron ore, gold and copper in other parts of the Tanzania to help fund its project.

BBC: S Korea 'in Tanzania land deal'