Rio Tinto will provide an additional $1.3bn for the development of the Simandou iron ore project in Guinea.
The firm will invest $211m in continued studies and $1.1bn in commitments for early works and procurement of long-lead items of the project.
Currently the firm is in the process of obtaining the required regulatory approvals with project partner Chalco.
Finalisation of the infrastructure investment framework is expected in early 2012, which will also require The Government of Guinea to contribute its share of infrastructure project expenditure.
The funding will allow the project to move forward towards a first shipment of ore in mid-2015.