Proterozoic Birmian rocks which consist of turbidite facies sedimentary sequences. There are two main types of gold deposits that occur in the Siguiri basin: laterite mineralization and in situ quartz-vein-related mineralisation. The laterite mineralization occurs as aprons of colluvial or as palaeo-channels of alluvial lateritic gravel adjacent to and immediately above the in situ vein-related mineralisation, which is hosted in meta-sediments with the better mineralization associated with vein stockworks that occurs preferentially in the coarser, brittle siltstones and sandstones.
- AngloGold Ashanti (NYSE:AU; JSE:ANG) operates the Siguiri mine, situated in the Siguiri district in the north-east of Guinea, about 850 kilometres from the capital city of Conakry. It produced 246 000 oz gold in 2005. Proved and probable ore reserves amounted to 60,3 million t grading 0,85 g/t Au
- Crew Gold Corporation (UK, TSX:CRU.TO) operates the Lefa mine (Lero-Karta mine), approximately 700 km north-east of Conakry. Proven reserves amount to 24,9 million t at a grade of 1,7 g/t Au or 1,43 million oz gold. After completion of a new CIP plant, expected production will be between 320 000 and 350 000 oz gold per year.
- Semafo's Kiniero mine is located 500 km north-east of Conakry in central Guinea. It produces approximately 60 000 oz of gold per year and has reserves of 5,07 million t averaging 3,12 g/t Au.
- Wega Mining is exploring gold anomalies in the north-eastern part of the country called Haute-Guinée, in Mandiana and Siguiri préfectures.
- Mano River Resources Inc (MNO.V) holds the Missamana and Gueliban Exploration Permits (totalling 49,800 ha).Through a joint venture Navasota Resources Ltd (NAV.V) has the right to earn a 60% interest in these permits.
- Cassidy Gold Corporation announced on December 4, 2007, that drilling resumed at the company's 100% owned Kouroussa Gold Project in Guinea.
- Siguiri Basin Mining Inc. (SBMI) has a joint venture with Consolidated Mining Inc which includes 5 miles of the Tinkisso river. A dredging permit was granted on August 9, 2002 for a period of 10 years. The permit is renewable in incremental five-year periods and it awarded the exclusive right to mine for gold and related minerals in the bottom sediments of the Tinkisso river.