Summary:
The SMSZ Project is underlain by a mixture of mafic to intermediate with subordinate felsic volcanic and sedimentary rocks in the west and north-central part of the property (Mako Series). Tarkwa-type conglomerates and sandstone (Dalema Series, Keniebandi Formation) occur in the central south portion of the Project Area extending to the Senegal Mali Shear Zone.
Mineralisation And Alteration
Gold mineralisation on the SMSZ Property is concentrated along a 43 km segment of the Senegal Mali Shear Zone and within associated secondary structures. Drilling and mapping have confirmed mineralisation in at least twenty-four areas, with five deposits—Gourbassi East, Gourbassi West, Mogoyafara South, Linnguekoto West, and Barani East—sufficiently advanced to support resource estimates. The remainder are at earlier stages of investigation but demonstrate strong geological continuity with the known deposits.
Mineralisation is characteristic of orogenic gold systems in the Birimian terrane. It is controlled primarily by deformation along regional and local shear zones, and by competency contrasts at lithological boundaries. Gold is typically associated with quartz veining and zones of sericite, silica, carbonate and pyrite alteration. In mafic rocks, chlorite is commonly present, and in felsic units, alteration may include albite.
The Gourbassi Area contains several deposits within a mixed volcano-sedimentary sequence intruded by felsic and mafic rocks.
Mineralisation at Gourbassi East occurs within felsic volcanic lenses interbedded with greywacke, siltstone and volcaniclastic rocks. These lenses are folded and show a sigmoidal geometry in plan. Gold is associated with networks of quartz veinlets containing disseminated pyrite. Visible gold has been identified at the margins of these veinlets in reverse circulation chips. The mineralised zone extends for approximately 950 m along strike and between 50 and 100 m in width. Higher grade intervals correspond to sites where the felsic lenses intersect northwest-oriented cross structures that acted as zones of dilation and fluid focusing. Artisanal workings follow these mineralised structures at surface.
At Gourbassi West, mineralisation is hosted by altered intermediate volcanic rocks and by quartz-rich sandstones and conglomerates of the Keniebandi Formation. It is spatially related to a silicified breccia corridor interpreted as hydrothermal in origin. Although the breccia itself is generally unmineralised, it defines a major deformation zone that focused fluid flow into the adjacent rocks. The deposit is delineated over 1,100 m of strike and up to 120 m in width. Mineralisation is open to the north and southwest and is marked by sericite-silica alteration, disseminated pyrite and quartz veining. Local flexures within the breccia corridor coincide with higher grade shoots, and the zone is currently exploited by artisanal miners through shafts and shallow pits.
Gourbassi Northeast is situated at the contact between intermediate volcanic rocks and an intrusive body described variably as quartz diorite to granodiorite. Mineralisation is contained within the foliated and altered margin of the intrusion along a shear zone traced for at least 500 m.
Linnguekoto West
Linnguekoto West is developed within a northwest-trending package of siltstone, quartzite and conglomerate adjacent to a northeast-trending mafic dyke occupying a shear zone. Mineralisation is hosted by quartz-veined and silicified sedimentary rocks adjacent to the dyke. Drilling has defined the zone over 500 m of strike and to a vertical depth of 140 m, with both extensions open.
Mogoyafara South
Mogoyafara South lies west of the main trace of the Senegal Mali Shear Zone. Gold occurs within quartzite, siltstone, conglomerate and felsic intrusions, with several stacked mineralised lenses over an area measuring roughly 1,900 by 1,300 m. The lenses are shallowly dipping and follow the intersection of northeast- and northwest-trending structures. Mineralisation consists of quartz veining, sericite-carbonate alteration and disseminated pyrite.
Barani East, Barani, Barani Gap, Keniegoulou and KE
The Barani Area consists of several deposits aligned along a structurally controlled corridor extending for approximately 2.5 km. The main host rocks are quartzite, siltstone, and limestone of the Keniebandi Formation, with local dolerite intrusions. Mineralisation is associated with a subsidiary shear zone parallel to the Senegal Mali Shear Zone.
At Barani East, gold occurs in moderately east-dipping zones defined by silicification, sericite alteration, and disseminated pyrite.
Barani Gap and Keniegoulou, located along the same structural trend, display mineralisation consistent with that at Barani East. Drilling indicates that the mineralised shear zone continues between these areas, with alteration and veining patterns similar to those at Barani East. The mineralisation remains open to the north and south.
The KE Zone, situated northwest of the main Barani trend, hosts shallowly dipping, north-trending lenses of quartz-veined and silicified sediments. This zone is interpreted to have formed in an extensional setting adjacent to the main shear corridor.
Kamana
The Kamana area (~12 × 5 km), located in the northern portion of the property, is underlain by NNE-trending quartzite, quartz-rich greywacke, and siltstone, intruded by northeast-trending dolerite dykes and largely covered by laterite.
Soa, Soa West and Kolon
The Soa, Soa West, and Kolon zones form a continuous NE-trending corridor (~6 km × 1 km) located along strike from Barani East. The area is marked by extensive artisanal activity, including multiple pits exceeding 100 m in length and plus 10 m deep.
Kousilli/Frikidi Zones
The Kousilli–Frikidi Zone is a 2.4 km × 700 m, open-ended corridor within the Keniebandi Formation, hosting north-northeast and northwest-trending, sandstone- and conglomerate-hosted gold structures.
Dambamba
The Dambamba area, situated between Barani East and Frikidi, covers a 650 m × 500 m zone of artisanal workings adjacent to the Senegal Mali Shear Zone. Gold is hosted in siltstone and shale of the Keniebandi formation.
Linnguekoto
The Linnguekoto Zone, located in the southeastern of the Farabantourou concession, is characterized by multiple lines of artisanal shafts exploiting quartz veins hosted in sediments and granite.
Mineral Deposits Being Investigated
The principal exploration targets and focus of exploration to date within the Kéniéba Inlier is what can most appropriately be termed orogenic gold. Common sub-types of this class of deposit type include lode, quartz vein and shear zone-related gold, with the underlying similarity being that they all formed as part of an orogenic (collisional) tectonic event. Other terms used to describe these deposits are mesothermal, shear zone-hosted and greenstone gold deposits.
Orogenic gold deposits, with specific reference to “mesothermal deposits”, are primary deposits formed at intermediate depths within the earth's crust. Shear zone deposits refers to the fact that the larger deposits are often in or immediately adjacent to large fault zones. Greenstone gold deposits are hosted in volcanosedimentary terranes associated with granitic intrusions, metamorphosed to greenschist facies metamorphic grade and are usually Archaean in age.
Orogenic gold deposits can be described as gold-bearing quartz veins, stringers and wall rock accompanied by only minor sulphides that are localised by brittle to ductile structures within variable rock types. These deposits account for up to 18% of the world's gold production, ranking them second only to production from placer deposits. Deposits range in size from 0.5 t to 1,600 t of contained gold with most.