Earlier this month the country’s new mining minister Mohammed Lamine Fofane said he was meeting with Rio officials to discuss planned changes to Guinea’s mining code, which would lift the government’s stake to 33%.

Previously the government announced that Rio could have only half of its concession for the project after already spending $US700 million on its development.

In a statement, Rio said the extension provided more time for both parties to continue discussions aimed at resolving “all outstanding matters” regarding the Simandou project.

Brazilian iron ore major Vale has paid $US2.5 billion for the other half of the mining rights at Simandou, which Rio is contesting, while Israeli diamond merchant Beny Steinmetz’s BSG Resources owns the Zogota project to the south of the deposit.

But with a binding agreement inked between Rio Tinto and its major shareholder, Chinese heavyweight Chinalco, last year, further muscle sits behind its timely development, with the pair to progress work through a joint venture managed by Rio’s Simfer subsidiary.

Chinalco, through its wholly owned Chalco subsidiary, will acquire a 47% interest in the JV by providing $1.35 billion to sole fund ongoing development work over the next two years, at which time it would be left with a 44.65% interest and Rio Tinto 50.35%.

The remaining 5% would be owned by the World Bank’s International Finance Corporation.

The Guinean government currently holds an option to buy up to a 20% stake.

The partners expect to start mining by 2015, but believe there is scope to expand beyond the 95 million tonne per annum rate in subsequent years.

Separately, Rio has also received a binding $US340 million offer from industrial mineral supplier Imerys to acquire its global talc business.

A period of exclusivity with Imerys has been agreed, and Rio intends to respond following consultation with relevant European works councils.

“The successful sale of our talc business would deliver good value to our shareholders and remains aligned with our strategic focus on large-scale assets,” Rio chief financial officer Guy Elliott said in a statement.

Mining major Rio also purchased off-market 360,000 of its own shares yesterday, lifting its holding to a little more than 4.67 million ordinary shares as treasury shares.

Shares in Rio were unchanged at $84.96.