Siguiri gold mine is situated in the Siguiri district in the north-east of the Republic of Guinea, West Africa; about 850km from the capital city of Conakry. The SAG concession consists of four blocks totaling 1,494.58km2. All ore and waste is mined by a mining contractor in a conventional open-pit mining operation. Processing is done via a CIP plant.
Mineral and Chemical Composition: This concession is dominated by Proterozoic Birimian rocks which consist of turbidite facies sedimentary sequences. There are two main types of gold deposits that occur in the Siguiri basin: laterite mineralisation (CAP) and in situ quartz-vein-related mineralisation. The laterites comprise mostly hematite, quartz and alumino-silicates remaining after residual weathering. The laterite mineralisation occurs as aprons of colluvial or as palaeo-channels of alluvial lateritic gravel adjacent to and immediately above the in situ vein-related mineralisation. The vein-related mineralisation is hosted in meta-sediments with the better mineralisation associated with vein stockworks, that occur preferentially in the coarser, brittle siltstones and sandstones. The mineralised rocks have been deeply weathered to below 100m in places to form saprolite (SAP) mineralisation. The practice at Siguiri has been to blend the CAP and SAP ore types and to process these using the heap-leach method. With the percentage of available CAP ore decreasing, however, a CIP plant was brought on stream during 2005 to treat predominantly SAP ore.
Recommended Concentrations and Limits
(at two Standard Deviations)
Au Pb Collection 0.88 ± 0.09 g/t
Specific Gravity 2.81 ± 0.16