The geological setting
The Busia and Busitema area sits within Archaean greenstone rocks continuous with the Kenyan and Tanzanian craton margin. Mineralisation is typically associated with quartz veining and sulphide zones, worked at surface by artisanal miners for a century.
Where the economics turn
Oxidised near-surface material is usually free-milling and recovers well through gravity and simple cyanidation. Below the oxide boundary, sulphide association raises the prospect of refractory ore requiring roasting or pressure oxidation, which changes the capital estimate by an order of magnitude.
Any project economics built entirely on oxide recovery assumptions carry an unpriced step change at depth. Ask for variability testwork across the transition, not composite averages.
What to demand from a technical report
Bottle roll and comminution data by domain, sulphide sulphur assays, and a stated position on where the oxide base sits. Reports that present a single recovery figure for the whole deposit are describing an ambition, not a flowsheet.