Boadi (1991) determined that the pyroxene-garnet gneisses are of volcanic and volcano-sedimentary origin and that the protoliths would therefore be consistent with typical Birimian lithologies; however, this protolith assessment does not categorically exclude Archaean protoliths.

The Tuzon and Dugbe F deposits can be broadly classified as being highly metamorphosed “orogenic type” deposits. Whilst orogenic gold deposits typically exhibit strong structural controls on mineralisation and are generally hosted within veins or shear zones or zones, these are not obvious at Tuzon and Dugbe F. Orogenic deposits elsewhere within the Birimian of West Africa belong to the mesozonal class and typically have structural controls of the brittle-ductile type. It is apparent that Tuzon and Dugbe F were subject to lower crustal hypozonal conditions with higher temperature and pressure within the ductile zone.

The upper amphibolite to granulite facies gneissic host rocks and the absence of wall-rock alteration at Dugbe F and Tuzon is atypical of Birimian deposits. Alteration may have been ‘obliterated’ by the high temperature metamorphism that post-dated the gold mineralisation. High-strain fabrics, possible ‘relic’ sheared intervals and micro-shearing at a crystal-scale, may be indicative of a major shearing event which is less obvious being ductile (without brittle aspects) which affected the bulk of the rock-mass of the host and immediate country rocks. It may be that ........

Mining of both the Tuzon and Dugbe F deposits will be executed through conventional open-pit methods of drill and blast followed by load and haul operations. Loading and hauling will be carried out through the use of 90t dump trucks and 200t excavators. Drilling and blasting will be performed on 12m benches for waste and 6m benches for ore, some of which will be loaded in 3m flitches.

The planned Dugbe F pits cover an area of approximately 2.5km by 1km and the planned Tuzon pit approximately 1.5km by 0.80km. Each pit will have a single adjacent large waste rock dump (WRD), eventually containing 280Mt of waste rock over an area of 270ha. Waste rock will be placed adjacent to the pits, or in areas of mined-out pits in the case of Dugbe F. WRDs will be progressively capped every year, and fully closed as sections are completed. Ore will be delivered to the crusher or to low-grade stockpiles to prioritise highergrade ore being fed to the process plant. The available small proportion of oxide ore will be blended into the hard rock ore before being processed.

Mining of the Dugbe F deposit will consist of three pits, namely north, central and main pit, with the main pit consisting of four pushbacks. Tuzon will consist of one main pit with four pushbacks over the life of the mine (LOM). Mining at Dugbe F will start a year after mining begins at Tuzon, with both deposits mined concurrently to keep the strip ratio low. The first five years will see an a ........

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The Dugbe Gold mine processing plant design has been based on a conventional milling and gravity gold recovery circuit followed by a carbon-in-leach (CIL) gold recovery circuit and has a fresh ore processing capacity of 5.0Mtpa.

The Dugbe Gold Project ore deposit is comprised of two mining pits, namely Tuzon and Dugbe F, which will be mined by open pit method to produce a life of mine (LOM) mill feed blend containing 71% Tuzon fresh ore, 26% Dugbe F fresh ore and 3% combined oxides, by weight. The process flowsheet includes conventional size reduction and mineral beneficiation unit processes as follows:
• ROM ore tip and primary crushing;
• Mill feed stockpile and reclaim;
• Milling and classification circuit which includes a primary semi-autogenous grinding (SAG) mill, secondary ball mill and tertiary Vertimill®;
• Gravity recovery within the tertiary milling circuit;
• Pre-leach thickener;
• CIL circuit;
• Acid wash, elution and carbon ........