Rio Tinto has decided to "gift" its shelved Bunder diamond project in India to the government of Madhya Pradesh.

The decision follows Rio's announcement in August 2016 that it would not proceed with the project, and a subsequent strategic review.

Rio Copper & Diamonds chief executive Arnaud Soirat said the exit from the project was another example of the company streamlining its asset portfolio.

"It simplifies our business, allowing us to focus on our world-class assets," he said.

"We believe in the value and quality of the Bunder project and support its future development, and the best way to achieve that is to hand over the assets to the government of Madhya Pradesh."

Goldcorp has entered into a binding agreement with New Gold to acquire New Gold's 4% gold stream on the El Morro deposit for $US65 million cash. 

The El Morro deposit is part of NuevaUnión, a 50/50 joint venture between Goldcorp and Teck Resources that combines the Relincho and El Morro deposits. 

"The purchase of the stream from New Gold is consistent with our strategy of optimizing our portfolio to drive increasing net asset value per share," Goldcorp president and CEO David Garofalo said. 

"El Morro is a world-class deposit, located in one of the best mining jurisdictions in the Americas."

Freeport-McMoRan said it continued to seek approval from Indonesian authorities for the export of copper concentrates from the Grasberg mine, in which Rio is also a partner.

The government wants Freeport to move from a contract of work (CoW) to a special mining business license (IUPK), and therefore forgo its current rights to fiscal and legal certainty, and commit to build a new smelter.

Freeport said failure to secure an export permit would see it drastically reduce production, at a rate of around 70 million pounds of copper and 70,000 ounces of gold for each month of delay.

Rio CEO J-S Jacques said on Wednesday that Freeport CEO Richard Adkerson was on his way to Jakarta for talks with the government.

Africa Finance Corporation has agreed to invest $US250 million in Alufer Mining to fund the development of bauxite deposits in Guinea.

The Bel Air and Labé projects have more than 3 billion tonnes of resources, with Bel Air slated to produce 5.5 million tonnes per annum with the next 18-24 months.

"As global demand for aluminium increases, AFC is proud to be the sole private sector African investor in the Bel Air mine, developing a world class mine that adheres to best practise environmental principles," AFC chief investment officer Oliver Andrews said.

Other partners in the consortium include Orion Mine Finance and Resource Capital Funds.

Guinean President Alpha Conde attended a ground-breaking ceremony at the project earlier this week.

Banro Corporation has reported the death of four people at its Twangiza gold mine in the Democratic Republic of Congo.

A group of armed robbers attempted to enter the site on Tuesday, with three mine police officers and one armed offender killed in the incident.

Another armed robber is in custody.

Nothing was stolen and operations continue uninterrupted.