The tin deposit is a cassiterite-bearing vein system adjacent and possibly distal to an underlying source granite. From the composition of the mineralization, it was concluded that the mineralization has a low temperature origin, with a probable granitic source. Fluorine and lithium are absent from the ore forming fluids and base metal sulphides are scarce in the cassiterite. The deposit has up to 0.5% rare earth elements (REE) and very high-grade tin (with some sample assays reaching >60% Sn). This may indicate the source granite to be at depth below the surface.

The age of the Bisie cassiterite is 1053 Ma to 1068 Ma – it therefore may have been precipitated penecontemporaneously with deposition of the host sediments. Ore forming processes at Bisie are, therefore, either related to a granite that is also circa 1060 Ma old and as yet undiscovered, or they are associated with synsedimentary exhalative processes and unrelated to a granite intrusion. In the latter case, Bisie mineralization may be more closely analogous to Neves Corvo in Portugal, where a tin-rich, stratiform, massive sulphide deposit has formed, than it is to deposits such as San Rafael in Peru.

The first phase of exploration diamond drilling was completed at Mpama South in May 2015 and comprised 16 drillholes (plus three re-drills) drilled from east to west and spaced 50-100m apart on seven drill lines for 3,364metres. This early phase of drilling served both as a confirmatory/discovery ........

The access to the Mpama South underground mining areas will be via an adit and access drive developed into the side of a hill on the footwall side of the deposit. The access drive will be horizontal to a point where the deposit is intersected at which point ramps will be developed both upwards and downwards in the footwall of the deposit to access the vertical extent of the deposit.

Due to the lack of site specific data, the properties used to design the Mpama North boxcut were benchmarked to be used for the Mpama South boxcut design. This data has been used to complete a conceptual design and to provide cross-sections through the boxcut and provide the recommended support requirements for the highwall and sidewalls, at a concept level of accuracy.

The slope angles used for the Mpama North boxcut were superimposed over the topography at the Mpama South boxcut location. The sidewalls were assumed to be excavated in soft or weathered material, while the highwall will be excavated partly through soft or weathered material and partly through more competent transitional mica schist.

The soft or weathered material was assumed to extend to between 25.0m and 30.0m below surface, therefore, the boxcut would need to be 30.0m deep. The bench heights of the highwall and sidewall should be limited to 10.0m, with a berm width of 6.5m. The highwall bench face angles should be limited to 80°, the sidewall bench face angles should be limited to 45°. All bench ........

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