The Geita Gold Mine is situated 80km south-west of the town of Mwanza in the north-west of Tanzania. The Geita gold deposit is an Archaean mesothermal orebody, located in the Sukumaland Greenstones of the Geita Greenstone Belt. It is largely hosted in a banded ironstone formation (BIF). Mineralisation is found where auriferous fluids, which are interpreted to have moved along shears often on BIF-diorite contacts, reacted with the BIF. Some lower-grade mineralisation can occur in the diorite as well (usually in association with BIF-hosted mineralisation). Approximately 20% of the gold is hosted in the diorite.
Mineral and Chemical Composition: The major gangue mineral is magnetite with quartz, ankerite, and minor pyrrhotite and chalcopyrite. Gold occurs primarily as discrete grains. Major and trace element chemistry data has been compiled but has not been certified. Summary statistics for this data are set out in the appendix.
Recommended Concentrations and Limits
(at two Standard Deviations)
Au Pb Collection 1.38 ± 0.14 g/t
Cu M/ICP 164 ± 17 ppm
S Combustion / LECO 4.45 ± 0.28 %
Specific Gravity 3.07 ± 0.12