Aluminum Corporation of China or Chalco (HKG:2600, SHA:601600) signed an amended mining convention with the Guinean government for a planned alumina project in Guinea involving a total investment of about $1 billion, according to a Friday Hong Kong bourse filing.

The development, located in Guinea's Boffa region, will include an alumina refinery with an annual production capacity of 1.2 million tonnes and supporting port infrastructure.

Under the revised agreement, Chalco will establish a project company to construct and operate the alumina project.

The Guinean government will immediately receive a 5% free-carried equity stake in the venture, with the option to increase ownership interest up to 35% by acquiring additional shares at fair market value.