The EMZ deposit is a greenstone hosted orogenic gold deposit. Specifically, it is a quartzcarbonate stockwork vein deposit hosted by a folded turbidite succession of arenite and argillite. The original structural interpretation and gold settings have been confirmed by mining.

Gold occurs as free particles within the veins and is also intergrown with arsenopyrite +/- tourmaline on vein margins or in the host rocks. Disseminated arsenopyrite in the host rock rapidly decreases away from the veins and is strongly associated with the gold mineralization. The same relationship is seen away from lithological contacts, which generally show higher densities of bedding-parallel veining. Oriented diamond core drilling shows that significant concentrations of gold with arsenopyrite can be found in the areniteargillite lithological contacts in association with quartz veining or in veinlets of massive arsenopyrite. Deeper below the main arenite unit, significant concentrations of gold are found in association with coarse arsenopyrite in the argillitic unit. The gold particles occur without sulphides in the weathered saprolite. The gold is free-milling in all associations.

The vein arrays occur in the east limb, fold hinge (or fold axis), and west limb litho-structural domains. The geology and economic potential of the EMZ deposit is dominated by the persistent east limb main arenite. The top contact of the east limb domain is a sharp, sheared contact with no significant gold mineralization above it. The shearing appears to be parallel to bedding, however, some loss of vertical succession has occurred. The main arenite below this contact is the lower coarse grained part of a Bouma cycle. The locus of bedding parallel deformation and alteration is within the east limb main arenite. Graphitic argillite occurs immediately above the contact. The deformation shifts into the hangingwall argillite unit to the north of the EMZ deposit.

Mineralization has been confirmed to over 550 m vertically below surface, however, the full depth extent in the fold hinge and east limb is still unknown. The geometry of the fold hinge zone is an anticlinal flexure that is easily recognized in the pit and oriented drill cores. The fold closure is sharp and sometimes truncated by thrusts and the transition from east limb to west limb takes place over a few metres. The position of the fold axis is often marked by a breccia in the arenite unit. The fold hinge zone in the argillite unit is marked by tight kink structures and sheath folds with rapid transitions from east dipping footwall rocks to nearvertical west limb beds below the fold axial plane.

Hydrothermal alteration and meteoric weathering are pervasive through the east limb main arenite. It is generally associated with quartz veining and gold mineralization in deformed main arenite. The alteration assemblage is sericite > carbonate > silica ± albite ± arsenopyrite ± pyrite. Disseminated tourmaline and rutile are found in accessory amounts. The main alteration minerals tend to occur in clearly defined veins and stringers.

The Falagountou deposit is a porphyry intrusive-hosted, orogenic style, gold deposit. Gold is commonly located within smoky quartz veins injected along the contact of the dioritic dyke and a sequence of fine-to-medium-grained detrital sediments. Gold is also disseminated into the rock. At both Guessakado (Falagountou’s orpailleur pit area) and the Falagountou Southeast Zone, vein occurrence is prevalent at the contact of the intrusion and sedimentary rocks.

Due to the intense artisanal mining (“orpaillage”) activity, no detailed geological mapping has been carried out over the Falagountou deposit. Observations, from visits within orpailleur workings, indicate that gold is located in smoky quartz veins injected in a sequence of fine to medium detrital sediments, similar to those found at the EMZ deposit that have been intruded and metamorphosed by shallow dioritic dykes.

Drill cutting and core observations have confirmed that the gold mineralization is structurally controlled, hosted in sheared and brecciated zones in the hanging-wall contacts between sedimentary and intrusive rocks along a north-northwest to north trend. Gold is associated with quartz veins and is found disseminated into the wallrock, as well. There is a strong spatial relationship between the gold mineralization structures and the swarm of intrusive dykes that intrude the sedimentary sequence, suggesting that part of the fluid responsible for the gold deposition may have been exsolved from the dioritic magma during its emplacement. The alteration assemblage encountered is silica-calcite-chlorite. Pyrite and arsenopyrite are the main sulfide minerals observed to date, both in sedimentary rocks and the dioritic dykes.

Mining is carried out using a conventional drill, blast, load, and haul surface mining method with an owner fleet. The annual mining rate was 48.9 Mt in 2015 with a stripping ratio of 3.24 including 11.52 Mt of ore at an average grade of 1.14 g/t Au for a total of 426 koz of gold.

Current pit geometry consists of five metre benches in the upper lateritic layers, and 10 m benches in hard rock.

Grade control is accomplished by RC drilling and sampling of the mineralized zone on a 10 m x 10 m pattern, or tighter as required. For sterile sections of the pit, the grid may be widened out based on the nature of the contacts and/or other geological occurrences.

A fleet of 11 drill rigs are used for the 150 mm (six inch) production blast holes with two additional 223 mm (nine inch) drill rigs, commissioned in 2015, for production in hard rock. The quantity of hard rock material to be mined (i.e. transition and rock) is increasing and will continue to do so for the remainder of the mine life.

Ore is processed using two stages of crushing, semi-autogenous grinding, ball mill grinding, pebble crusher grinding (SABC), gravity concentration, and a carbon-in-leach (CIL) gold plant. The UFS proposed a process plant throughput rate of 7.5 Mtpa. During construction, some debottlenecking improvements were made to the design, resulting in a revised nameplate capacity of 9.0 Mtpa based on processing 100% saprolite ore. Due to further operational improvements, plant throughput has increased beyond the constructed design capacity.

Fresh rock mill feed has gradually increased from 2012 onwards. To maintain gold production levels, with increasing proportions of hard rock in the mill feed, an expansion was completed in 2014. The objective was to double the hard rock processing capacity from 5.4 Mtpa on a 100% hard rock basis to 10.8 Mtpa.

The ore coming from the mine is crushed in a gyratory crusher and in a cone crusher. The crushed ore is stockpiled either in a pile for Line A or Line B. The ore is reclaimed with apron feeders and feeds SAG mills on each line. The pebbles from the SAG mills are diverted to their respective pebble crusher in closed circuit. The ore passing through the SAG mill discharge screen feeds a pack of cyclones. Cyclone underflow returns to the ball mill. Cyclone overflow is sent to the pre-leach thickener. A portion of cyclone underflow goes to the gravity concentrators (two on each Line).

The thickened ore feeds two parallel lines consisting of one leach tank followed by CIL tanks. Once loaded with gold, the carbon is screened, acid washed, and eluted. The pregnant solution is sent to the gold room for electrowinning, drying, and finally, smelting into doré bars.

Eluted carbon is regenerated in a kiln and reused in the CIL circuit. Carbon fines generated from the circuit are recovered in bags for further gold recovery.

The gravity concentrate feeds a shaking table. The concentrate obtained from the table is then dried and smelted.

In addition, the carbon fines treatment plant and the intensive leach reactor (“ILR”) were both commissioned in the second quarter 2016. The carbon fines treatment plant will help increase saleable gold by facilitating the processing of carbon fines material on site and the ILR will further help improve overall recoveries.