Allen & Overy has advised a subsidiary of China Power Investment Corp. on an alumina mining contract with the Republic of Guinea that is part of a $6 billion project in the West African country.

The state-owned electricity producer is planning a major development in the coastal city of Boffa, including an alumina refinery, deepwater port, and coal-fired power plant. The project will also include a bauxite mine that is expected to produce 4 million tons a year. Bauxite is processed into alumina and then into aluminum.

In a statement, Allen & Overy said the mining contract was a foundational agreement for the project at large. The firm’s team was led by Beijing partner Matthias Voss, Paris partner Alexandre Ancel, and Perth partner Meredith Campion.

King & Spalding acted for the government of Guinea, with a team led by London partners Garry Pegg and Hywel Jones. Local firm Sylla & Partners advised on Guinean law matters.