Gold, sulphosalt and telluride mineralogy of the Lega Dembi shear-zone hosted gold deposit, Ethiopia

摘要

The gold mineralogical of quartz-sulphide ores at Lega Dembi has been investigated. Finegrained gold (native gold, electrum, tellurides) locked within pyrite and intimately associated with Pb-As sulphosalts is the main reason for lower-than-typical gold recoveries in quartz-sulphide ore. This As-dominated association is previously unreported from Lega Dembi and contrasts with a Pb-Sb character at higher levels. Tellurides are locally abundant and petzite accounts for a minor amount of Au in the ores. Assemblages and textures are explained in terms of exsolution and syn-deformational remobilization.