Mining Plus has been unable to visit the site and thus is unable to confirm the deposit type as described in Woodman and van Osta (Woodman, 2007). They describe the principal deposit at Dibaas analogous to the Sadiola Gold Mine, located 20km north of the Diba project. However, the Sadiola deposit occurs in rocks assigned to the Kofi Formation, whereas the Diba discovery occurs in rocks assigned to the Kéniébandi Formation. Until the discovery at Diba, no significant gold deposits had been recognized in the Kéniébandi Formation of western Mali.

Other gold deposits in the region include Sadiola, Loulo, Tabakoto, Segala, Gara, and Yalea. Lawrence et al (Lawrence, 2013) assigned the gold-bearing deposits located along second-or higher-order shears associated with the Senegal-Mali shear zone to the orogenic gold deposit type, developed along strike-slip fault systems linked to late-stage, non-orthogonal, orogenic crustal growth.

Common features of the orogenic gold deposits in the Kéniéba-Kédougou inlier are their shear-hosted character, the intimate association of the gold mineralization with permeable lithologies and fractured host rocks, producing stratabound mineralized bodies, and the link between gold mineralization and carbonatisation and Fe-rich alteration.

The source of orogenic gold has been strongly debated. In particular, the composition and source of hydrothermal fluids that sourced the gold mineralizationin Mali had been poorly studied until very recently. Simon and Pizarro (Simon, 2013)reviewed a detailed geological study at Loulo, which included fluid-inclusion investigations, and determined that low-salinity, reduced, CO2-richmetamorphic fluids were associated with gold mineralization at Loulo, which is consistent with many orogenic gold fluid studies worldwide. The geological study considered the hyper-saline fluid as being related to a magmatic source, and its presence points to the potential role of multi-fluid sources in the formation of orogenic gold deposits. Gold precipitation may be, therefore, linked to fluid mixing between metamorphic and magmatic fluids, thus increasing metal fertility and leading to the formation of world-class orogenic gold deposits

Gold mineralisation modelled at Diba extends over an area measuring 700m x 700m. Anomalous gold at theDiba / Korali Sud property extends over 2.5km north –south (Woodman, 2007), and is defined as auger sample values >0.1g/t Au.

No sulphide or gold mineralisation has been intersected in the LCS. Gold mineralisation is strata-bound and constrained to the UCS. The sulphide content of the mineralised lenses is typically less than 10% by volume, and commonly as little as 1%. Disseminated sulphides are fine-to very-fine grained, and consist dominantly of pyrite, with a minor amount of arsenopyrite, chalcopyrite, tellurides and native gold.

Calcite is a ubiquitous constituent of the rocks at Diba, typically 5 -20% of the overall mineralogical composition. The mineralized dark-grey siltstone is strongly reactive to hydrochloric acid. Calcite also often occurs in veinlets and irregular pockets. The distribution of pyrite relative to calcite is inconsistent, but sometimes pyrite develops marginal to calcite crystals. Associated veinlets consist of millimetre-thick bedding-parallel veinlets of pyrite with subordinate amounts of calcite-quartz-biotite.

According to the report by Simon and Pizarro (2013), gold mineralisation in the Property is represented by native gold and calaverite within graphite, biotite and quartz-bearing silicates, and by native gold as inclusions in carbonates. Grain sizes vary between 3 -100 µm, and all are believed to have formed during hydrothermal processes. The absence of silver in calaverite would suggest moderate to high temperature of crystallization.

Simon and Pizarro (2013)also reported native gold in biotite-altered domains that contain aggregates of fine-grained titanite and rutile, as a rim on epidote, as minute inclusions in recrystallized feldspars of a sericite+biotite-altered siltstone. The strong association of gold with biotite, sericite and carbonate suggests its mobilisation and concentration during hydrothermal processes. No visual guides for determining the presence of mineralisation in the drill holes have been identified. The depositis characterized by an Au+Ag+As+Te±Sb geochemical signature.

Based on the continuity of mineralised zones >0.3g/t Au, and the interpretation of the mineralisation as sediment-hosted, disseminated epigenetic deposit, Mining Plus modelled the zones of the deposit as a series of 8 stacked lenses. These were given restricted continuity along strike and at depth.

The mineralised units extend horizontally over a 700m x 700m area, and the mineralised bodies are usually shallow-dipping (30 degrees east –ESE) and generally 20 –40m thick. The spatial distribution of the gold grades dipping approx. 30oESE supports the interpretation of the stacked lenses modelled with the grade shells.

As mentioned previously, the spatial distribution of the gold grades dipping approx. 30oESE supports the interpretation of the stacked lenses represented bythe grade shells. Simon and Pizarro (2013) reported that the Au values appear to be oblique to the primary bedding of the host units, although no major ductile-brittle faults have been identified in drill core.

Therefore, although it is postulated that bedding planes may have been major conduits for the gold mineralising fluids, the bedding does not appear to control the geometry of the mineralised lenses.

The general NE orientation of the axis of the mineralized units at the Property is oblique to the dominant N-S regional tectonic orientation, and to major structural discontinuities of the district. The deposit may be structurally controlled by possible NE striking faults linked to the transcurrent sinistral motion on the regional extensive Senegalo-Malian fault which bounds the Kéniébandi Formation to the east.

Mining Plus noted during wire framing and modelling of the mineralisation that there is a poorly mineralised E-W trending zone in the middle of the deposit that may represent a structural discontinuity. There is also a NE-SW trending high-grade portion of the deposit defined in the upper portion of the oxide zone, which is not understood at this stage.

On a local scale, the calcareous sequences have been affected by very weak deformation processes. A weak bedding-parallel foliation is only apparent locally, and corresponds to a compressional event. Primary structures are well preserved in several drillholes.

The ultimate pit shell selected as the basis of this PEA is Pit 99 with a revenue factor of 100%. Tonnage of Potential Mineralized Inventory (PMI) content inside the selected pit shell includes 3,955 kt of indicated resource category and 749 kt of inferred resource category with an average grade of 1.37 g/t of Au and includes a stripping ratio (waste:PMI)of 1.33.

A conceptual mine design has been completed based on the optimal pit shell generated, assuming the use of articulated trucks with 20m3tray capacity. The pit design was prepared using a minimum mining width of 30m with a ramp width of 12m and 10% gradient. Slope angles used are 50° for the oxide zone, and 65° for the fresh rock zone.

Production planning considers two possible scenarios, the first based on a processing capacity of 1.5 million tonnes per year, and the second based on 1 million tonnes per year.

Both mining plans require initial waste stripping using 2 x CAT365 excavators. Mining would be via conventional open-pit methods (drilling, blasting, loading, haulage and ancillary services). The use of a mining contractor for earth movement has been assumed for both mine plans.

Both scenarios consider the mining of PMI with the highest grade in the first months with the aim being to maximise the NPV for the project.

The life of mine (LOM) for scenario 1 is 39 months, and for scenario 2 is 57 months.

Due to the relatively short mine life (<10 years) and given the production rates considered in Scenarios 1 and 2, the use of articulated trucks has been considered for the Diba Project.

The parameters used for drill and blast consider different blast patterns depending on the rock characteristics. Blast patterns of 3.2m x4.3m for the oxide zone, and for the fresh zone a blast pattern of 2.8m x 3.22m were assumed.

For loading of the material, an excavator with bucket capacity of 4.6 m3(CAT360 or similar) was considered. This excavator requires approximately five (5)passes to fill an articulated truck of 30t capacity. Two excavators are required for the first 4 months to complete initial waste stripping and expose the mineralised material.

Conceptual mine design, production planning, operating and capital cost estimates have been developed for an open-pit operation.

A two-stage crushing circuit has been proposed to reduce the Run-Of-Mine (ROM) oxide material to finer than 25mm. The crushing circuit will include a jaw crusher, a vibrating screen, a cone crusher, an optional agglomerator and related mobile conveyors.

The ROM material will be transported from the open pit to the crushing plant by haul trucks. The haul trucks will dump into ROM bin which will feed mineralised material onto a belt conveyor for transport to the primary jaw crusher. A Front-EndLoader (FEL) will also be used to reclaim the stocked ROM material into the ROM Bin according to the mine plan. The jaw crusher product will be discharged onto a second belt conveyor and fed onto a vibrating screen to remove undersize material from the feed to the secondary cone crusher. Screen oversize will report into a surge bin ahead of the secondary cone crusher. The surge bin enables feeding of the cone crusher at a steady rate, which improves the crusher operating efficiency. The discharge of the cone crusher is planned to be finer than 25mm.

Further studies are required to test the crushing circuit and understand the size fractions likely to be produced at each stage of crushing. If significant fine material is produced then a agglomerator will need to be addedto the process. The undersize material from the vibrating screen and the crushed material from the cone crusher will feed onto a common conveyor that will transport the material to an agglomerator. Cement will be added to the content on the conveyor as it feeds into the agglomerator, which will cause the fine particles to agglomerate with the coarser particles. Spray water will be added into the agglomerator to improve agglomeration efficiency. The agglomeration before placing the crushed material onto the heap leach pad will improve the permeability of the heap and therefore enhance the effectiveness of gold extraction in the heap leach operation. Lime will also be added to the crushed material before placement to control the alkalinity of the heap leach. The agglomerated material will discharge onto a crushed material stockpile adjacent to the crushing plant for curing.

The processing facilities proposed for the Diba project include:
• Two-stage crushing, screening, and agglomeration
• Heap stacking and leaching
• Gold recovery by Carbon-in-Column processing.

Heap Leaching
The heap leach pad will be an engineered structure that will consist of a gravel or sand base covered with a clay liner, covered with an impermeable synthetic geomembrane. Impermeable berms will surround the perimeter of the leach pad. The pad will gently slope to a central PLS collection pond on the downside of the pad. The solution collection pond will also have an impermeable geotextile liner.

The leach pad will be designed to withstand the loading of crushed material and the movement of heavy equipment on top. A Leak Detection and Recovery System (LDRS) including ground wells, will be installed at the heap leach pad and the solution ponds to detect any solution leakages.

The crushed and agglomerated material will be reclaimed ........