Geology and mine exploration trends of Prestea Goldfields, Ghana

Abstract

Prestea Goldfields occurs in the Precambrian Upper Birimian series which is represented by northeasterly dipping phyllites, metatuffs, metagreywackes and carbonaceous phyllites. The mineralized zone is made up of three channels, namely; the main reef channel, the west reef channel, and the ‘B’ or east reef channel. The ore bodies are localized in these three channels. The occurrence of tectonic movements has resulted in the formation of extensive fault gouges along one or both contacts of the reef and wall rocks, but in places, the fault gouges cut through the reef. Wall rock alteration occurs in the form of pyritization, arsenopyritization, sericitization, chloritization, silicification, and carbonatization. The most abundant ore minerals are pyrite and arsenopyrite, each making up 20–30% of all the ore minerals. Gold is commonly associated with bournonite and bonanza ores are associated with mariposite. This paper analyses the present method of exploration. Initial drilling into the footwall has shown good values in the metavolcanic rocks.