Segilola Resources Operating Ltd. (SROL) is a company, domiciled in Nigeria, that operates the Segilola Gold Project, located in Osun State Nigeria. SROL is a wholly owned subsidiary of Thor Explorations Ltd.
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Summary:
Segilola is an orogenic-style lode gold deposit which occurs within a regional-scale shear zone.
Host rocks comprise an overturned sequence of high-grade amphibolite-facies metasediments intruded by a large, possibly differentiated, granodiorite sill-like body. The mineralisation is developed within a series of steeply dipping, tabular, very continuous, late stage quartz-pegmatite veins that do no exhibit any form of significant deformation such as folding or faulting. The geological and mineralogical characteristics of the mineralised veins are consistent throughout both the strike and down dip extents of the known resource.
Drilling results demonstrate that gold mineralization occurs in fractured pale to dark grey coloured smoky quartz veining, sheared pegmatite, and silica/chlorite/carbonate alteration. The mineralization is hosted in three steeply dipping vein sets or lodes; the Hanging Wall Lodes (Lodes 100 and 300, and minor lodes 400, 500 and 600) and the Footwall Lode (Lode 200). Together these form an elongate mineralized zone striking 010° and dipping 60° to 70° towards the west within a developed shear zone, primarily in biotite gneiss. The currently drilled mineralized zone is approximately 2,000 m in strike length, between 70 m and 200 m in depth, and between 2 m and 18 m in true thickness.
The mineralogy of the Segilola deposit is characterised by its general simplicity and consistency. The gold is entirely non-refractory and commonly occurs as visible particles within either pegmatitic quartz-feldspar veins or foliated biotitic selvedges to the veins. There are no significant trace element associations such as silver with gold. However, metallurgical assaying indicates slightly elevated copper (250 ppm to 300 ppm) and mineralogical studies suggest a gold-tellurium association.
Two styles of gold mineralisation are observed:
• Narrow, 1 m to 3 m thick Hanging Wall Lodes within silicified biotite schists (DGS). These lodes locally contain 5 µm to 20 µm grains of visible gold and are developed in the hanging wall to the main (footwall) lode. These lodes appear to have different controls to the footwall lode and have a more vertical continuity over shorter strike lengths.
• Wide, up to 15 m, ‘footwall’ mineralisation within a characteristically grey-green, strongly silicified zone of biotite schists and gneisses (SZQ1).
The mineralised lodes generally comprise highly silicified fine-grained, foliated biotite gneiss typically intruded by both discordant and concordant pegmatitic quartz-feldspar veins.
Shearing, fracturing, and alteration influence the location of gold mineralisation. This relationship has generated multiple zones of gold mineralisation hosted by shears now represented by chlorite and calcite alteration, together with quartz veining and pyrite development.
Minor sulphides, typically pyrite, are associated with the lodes. Macroscopic observations show that sulphide grains and blebs are often aligned with foliation, commonly following either biotite-rich laminae or near pegmatite boundaries. There is also, however, a common generation of pyrite occurring along fractures or as quartz-pyrite tension gashes, highly discordant to the foliation. A cursory examination suggests most of these do not contain pyrrhotite. These either relate to a late episode of mineralisation, or to remobilisation of sulphides.
Native gold is visible in both altered wall rock and in quartz-feldspar veins. It occurs with petzite (a silver-gold telluride), within pyrite, and quartz veins. The typical size of native gold blebs is approximately 10 µm. Gold, either as native grains, flakes and blebs occurs together with gold-on-pyrite in alteration zones, along tension gashes, hair-like fractures, joints, and minor faults.