The project area is prospective for mesozonal “lode gold” deposits which typically have a structural component and display a strong relationship to regional scale shear zones. Similar deposits can be found in other areas of the late Proterozoic Birimian terranes of West Africa. Gold mineralisation is typically associated with networks of quartz mineralisation or associated with disseminated sulphides within strongly deformed alteration zones.

At Balogo there have been at least three distinct mineralisation styles recognised. These include:

1. High-grade gold mineralisation (+/- Cu, Bi, Te) hosted in a sequence of diorites (as defined by drilling at the Netiana deposit over a length of approximately 500 m to a depth of approximately 250m). Mineralisation is restricted to a single dioritic unit which has a structurally-controlled hanging-wall contact with a distinct unit of chloritic metasediments. High gold grades are typically associated with quartz veining within the dioritic rocks. Figure 10 shows diamond drill core with this style of lost lithology.

2. Massive magnetite associated copper-gold mineralisation. This style of mineralisation outcrops near Cobra Hill and occurs as generally massive magnetite (+/- copper) gold mineralisation. Mineralisation is probably shear controlled and generally is hosted in metasediments immediately above the structural contact between metasediments and dioritic intrusives.

3. Copper-gold mineralisation associated with disseminated cumulate magnetite in a porphyritic intrusive. Mineralisation consists of disseminated magnetite, pyrite + chalcopyrite in a moderately to strongly silicified porphyritic dyke. The dyke is around 40 m thick, strikes eastnortheast and dips steeply west. Broad zones of low-grade copper/gold mineralisation are erratically distributed within the dyke unit.

The proposed method of mining for Netiana is a conventional open pit method using drilling and blasting, loading with excavators, and hauling with articulated dump trucks (ADT). The ore will be extracted by hydraulic excavators (30 to 40t) to maximise selectivity where the ore body is narrow, and the waste will be loaded by slightly larger hydraulic excavators (60 to 80t) to allow for higher productivity.

There is potential for additional Mineral Resources to be exploited by open pit mining methods, although this is dependent on improved project economics and/or reclassification of the Inferred Mineral Resources through additional drilling. Consideration of underground mining has not been necessary at this stage of the Project, although if the minerals were found to continue at depths beyond economic open pit limits then this could be considered in the future.

The evaluation of Netiana assumes that the ore will be transported to the processing facility at Youga. The optimal production rate is constrained by the capacity limit of the plant at Youga. Consideration also has to be given to the maximum vertical advance rate as the pit limit at surface is relatively small in area (250 m x 300 m) and the pit extends to a depth of 100 m below topographic surface. The mining rate was therefore set at between 300 and 680 Kt/month.

The Youga processing plant uses the conventional gravity/CIL gold recovery process, similar to various facilities in operation in West Africa. This consists of a 3-stage crushing operation, ball milling, gravity concentration and cyanidation by carbon-in leach (CIL). Pressure Zadra elution is utilized for recovery of gold from loaded carbon.

Crushing Circuit:

Run of Mine (ROM) ore is delivered to the primary crusher feed bin by front-end loader (FEL). Ore is withdrawn by a variable speed apron feeder to the primary (jaw) crusher. The crushed ore is conveyed to the secondary (cone) crusher, which operates in open circuit. The secondary crushed product is fed to a single deck screen (14 mm openings to produce a nominal -12.5mm crushed product), with the screen oversize reporting to the tertiary crusher section (two cone crushers in parallel) feed bins, while the screen undersize reports to the fine ore stockpile feed conveyor. The tertiary crushed products report back to the single deck screen, completing the circuit.

Milling Circuit:

The crushing circuit product reports to the fine ore stockpile, from which feed to the grinding circuit is withdrawn by one of three vibrating feeders onto the mill feed conveyor. Hydrated lime is added via a rotary valve onto the conveyor to ensure the ground ore is fed to the leaching circuit at the correct pH (>10.5). The ball mill discharge is pumped to a ‘cluster’ of hydro-cyclones, the overflow product from which forms the feed to leach circuit. The underflow product returns to the mill feed after a portion (approximately 20%) is diverted to the gravity circuit.

Gravity Circuit:

The bleed stream is passed over a vibrating scalping screen to remove coarse (+2mm)
particles, which gravitate back to the mill inlet chute. The underflow feeds the centrifugal bowl type concentrator for recovery of the coarse free gold and other particles of sufficiently high specific gravity. Concentrator tails gravitate to the mill feed inlet, while the concentrate is periodically discharged from the concentrator and flows into a storage tank located in the gold room for upgrading by further gravity devices.

Leaching circuit:

The cyclone overflow slurry flows onto a linear trash screen for removal of natural and mining debris such as woodchips, cloth, plastic and wire which can cause operating issues in the downstream stages. The slurry gravitates through a sampler and into the first leach tank (mechanically agitated) where cyanide solution is added. From there it overflows and gravitates through five subsequent, mechanically agitated, Carbon-in-Leach (CIL) tanks to enable maximum possible dissolution of gold as a cyanide complex and subsequent adsorption onto activated carbon. Each CIL tank is equipped with an interstage screen mechanism, with a cylindrical basket-type stainless steel wedge-wire screen surface for retention of activated carbon in the tank. Air blowers installed on the top of the CIL tank platform provide air in the slurry through the agitator shaft in order to improve oxygenation of the slurry and enhance the dissolution process.

Tailings:

The barren slurry from the last CIL tank gravitates to a vibrating screen (Carbon Safety Screen) prior to a sampler, and then to the tailings pumping station from where it is pumped to the slimes dam. Any carbon recovered from the screen will be re-circulated as required.

Carbon Treatment:

Barren carbon is added to the last of the CIL tanks and advanced through to the first where the loaded carbon is routinely removed from the circuit, washed in acid, and the adsorbed gold removed by washing in cyanide under pressure and temperature. The desorbed gold is recovered by electrowinning onto steel wool. The electrodes are routinely ‘harvested’, and, combined with the separately collected gravity concentrate, converted to bullion by smelting.