Summary:
The mineral deposits on the property include Salman Trend and Adamus deposits and also several smaller deposits (Bokrobo, Akropon, Nfutu, Aliva and Avrebo). Salman Trend gold deposits are believed to be associated with the same beltmargin shear zones that host the other Ashanti Belt gold deposits and has many characteristics typical of these deposits.
Major gold deposits in Ghana are hosted by proterozoic rocks of the West African Craton, including the Birimian Supergroup, a series of metavolcanic and metasedimentary rocks, the Tarkwaian Group, comprising fluvial metasedimentary rocks, and various gabbroic to granitic intrusives. Gold mineralization within the Birimian Supergroup is structurally controlled and associated with mesothermal quartz veins and sulphide concentrations, while both mesothermal shear hosted and palaeoplacer gold deposits occur in the Tarkwaian Group. The Nzema Project is within the Birimian Supergroup rocks with minor granitic intrusions, bounded by large granitoid bodies to the west and east, and is devoid of Tarkwaian Group rocks.
The Salman Trend is defined by a semi continuous +200ppb gold in soil anomaly extending for at least 9 kilometres along the Salman Shear Zone. Approximately 8.5 kilometres of strike extent has been drill tested to date with several discrete, multi-lode gold deposits identified along the shear zone. Significant oxide gold deposits within the Salman Trend include, from south to north, Salman South, Salman Central, Nugget Hill, Teberu, Salman North, North Hill, Akanko South, Akanko Central, and Akanko North. Salman Central, Nugget Hill and Salman North deposits are located on the shear zone at conspicuous north to north-northwest bends (left-hand flexures) within the overall north-northeast strike of the shear zone.
The Salman Shear Zone is made up of a western hangingwall comprised of 10-125 metres thick deformed phyllite and thin bedded greywacke with S-C bands and graphitic mylonite zones, and an eastern footwall of thick bedded greywacke with minor sheared phyllite zones up to a few metres thick. Boudinaged S0-parallel quartz veins and greywacke beds are a characteristic feature of the hangingwall zone.
At Salman South, Central and Nugget Hill gold mineralization occurs in west dipping lodes approximately parallel to and splaying out along the main Salman Shear. Most of the gold lodes are within the immediate footwall within quartz-veined silica-sericite-carbonate altered greywacke and/or granite with disseminated arsenopyrite. Some narrow, shear zone parallel zones of gold mineralization are present in the hangingwall graphitic phyllite. The mineralized zone at Salman Central gradually transgresses the shear zone from mostly footwall-hosted at the southern end to mainly hangingwall-hosted at the northern end.
Gold mineralization is associated with a complex array of deformed quartz veins and arsenopyrite disseminations in silica-sericite- carbonate altered metasediments and granitoid.
Most quartz veins are small (<2m thick and <10m long), and locally constitute up to 20 per cent of the rocks. At least five types of quartz vein sets are identified, all to some degree mineralized. Gold mineralization does not appear restricted to a particular vein set or sets, and there are zones where some vein types appear barren; the same vein types being mineralized elsewhere.
The Adamus gold deposit, approximately 9km west of the Salman Trend, is hosted by a northwest striking, northeast dipping package of greywacke (footwall) and interbedded greywacke-phyllite (hangingwall). In the western (footwall) part of the deposit, gold mineralization is also hosted by a steeply northeast dipping granite dyke that gradually converges on the hangingwall to the northwest. Three cleavages are present: north-northeast striking S2, east striking S3, and locally a subhorizontal S4. Gentle to open, metre-scale F2 folds are widespread, and small-scale open dome and basin F2-F3 interference patterns were locally observed in outcrop. The few facing directions observed suggest the meta sedimentary package is overturned.
Gold mineralization is intimately associated with pyrite disseminated within and around a complex array of deformed pale grey to dark smokey grey quartz-carbonate-sericite±albite veins. A broad silica-sericite alteration zone about 200 metres thick and 450 metres long is developed in the footwall greywacke sequence and in some areas obliterates primary sedimentary structure. The silica-sericite alteration zone is more extensive than the gold-pyrite mineralization. Unlike the Salman Shear Zone, there is no significant component of refractory gold in the sulphide zone at Adamus. The surface projection of identified mineralization trends northwest for approximately 900 metres and is up to 400 metres wide. Within this zone seven distinct domains of varying orientation and style were used for the resource estimation.
Most of the gold mineralization is located in the south-eastern part of the deposit where a very broad, modestly north-west plunging (35°) zone transgresses the hangingwall greywacke phyllite sequence into the intensely silica sericite altered footwall greywacke unit. This broad zone passes upwards into an extensive horizontal mineralization zone around 50 metres beneath surface in the weathered zones. Mineralization becomes sporadic along trend to the northwest until the northern end of the granite intrusive is encountered. Limited drilling along the granite intrusive also indicates the presence of northeast dipping lodes parallel to the granite margins.
The Bokrobo deposit is situated on the Nkroful mining license, 3.2 kilometres south-southeast of Adamus and comprises generally north-south trending, steeply west dipping auriferous quartz veins hosted by strongly silica and iron carbonate altered, medium to coarse grained, carbonaceous greywacke. A north-south trending dolerite dyke, dipping sub-vertically to the west cuts the depth extension of the main vein. In the southern portion of the deposit, a west northwest to eastsoutheast trending, steeply south-southeast plunging ‘dyke-like’ granitic intrusion is cut by numerous auriferous quartz veins forming a sheeted vein system. In the north of the deposit, mineralization generally occurs in a single lode, but in the south, the mineralization occurs as two main lodes and a series of narrow stacked lodes around or in the outer margins of the granite intrusion. Current interpretation has the main mineralization event occurring post-granite intrusion and prior to intrusion of the dolerite. Some remobilization occurred in favourable structural sites probably syn-dolerite intrusion.