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 campaign to test below artisanal mine workings and as a delineation exercise to ascertain scale and grade at Mpama South. No Mineral Resources were declared.

In December 2020, drilling restarted at Mpama South to define a Mineral Resource and delineate the further extents of the mineralization which were still open on strike and at depth. As at the effective date of this report, 34,963.55m in 140 diamond drillholes have been drilled and logged at Mpama South, with drilling still on-going presently. Some of these drillholes were drilled from west to east from drill platforms in the footwall initially but the majority was drilled from east to west and spaced 40 – 80m apart.

The strike length of mineralization has grown substantially at Mpama South since drilling recommenced in December 2020 to around 1,150 metres. The Mpama South mineralization intersected by drilling now extends northwards up to the southern end of the Mpama North Mine. A cross-cutting faulted area known as ‘The Wedge’ separates the two deposits. Alphamin believes that Mpama South and Mpama North formed one contiguous deposit, which is separated by the NW-SE striking ‘Wedge’ fault dipping steeply towards the SW.

The fault appears to be dextral and observations of the projected outcrop indicate that is has offset the main zone of mineralization at Mpama South westwards of the zone at Mpama North by ~75 metres. The fault zone itself is ~15 metres wide and appears to contain discontinuous cassiterite mineralization of a highly brecciated and low-grade nature. Further drilling in the wedge area from underground at Mpama North is underway at the time of writing.

Depth of mineralization at Mpama South is observed from surface in weathered outcrop to an RL elevation of about 350 metres, equivalent to approximately 450 metres vertical extent. Artisanal miners targeting cassiterite in the weathered outcrop excavated adits horizontally and vertically to a potential maximum depth of 70m.

3D Mineral Resource modelling delineated seven continuous discrete tin (with minor copper) mineralized zones at Mpama South in a stacked/parallel configuration. MZ1 and MZ2 represent the two main zones of the Mineral Resource and are continuous for 900 m and 650 m along strike respectively, and both have a down dip extent of 350 m and vary from as little as 1 metre up to 14 metres thick. Four zones are below the main zones and towards the south (MZ3 – MZ6) and one is in the hangingwall. They range in thickness from 1 – 9 metres with average thicknesses of typically 1.0 – 1.5 metres for MZ3 – MZ5, 4.0 metres for MZ6 and 0.5 metres for MZ7.

The two main zones of mineralization (MZ1 and MZ2) have similar average tin grades at a 0.5% Sn cut-off of (2.22% and 2.11% respectively). The smaller, footwall zones (MZ3 to MZ5) are higher in tin grade with averages ranging from 3% to 4.41% while MZ6 and MZ7 are lower in tin grade, with an average of 0.63% and 1.07% respectively.

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 benches will need to be supported to ensure slope stability.

The boxcut slopes will need to be supported with a combination of 2.4m long full column grouted tendons on a 1.5m spacing and 4.0m long end-anchored 25-ton cable anchors on a 3.0m spacing. The bolts should have a minimum diameter of 20.0mm and a minimum load carrying capacity of 100.0kN.

Additionally, all the exposed surfaces of the boxcut must be wire meshed and shotcreted to prevent unravelling of loose material. The shotcrete should be 50.0mm thick. The wire mesh must be galvanized chain link wire mesh with an aperture of 100.0mm and a minimum strand diameter of 3.5mm. The wire mesh should be secured to the excavation surface using tendons with base plates whose diameter should be at least 50mm larger than the wire mesh aperture.

A number of mining methods could be considered for the mining of the Mpama South Orebody, which include:
- Shrinkage stoping.
- Long hole open stoping.
- Drift and fill.

Cut and fill mining was initially used at Mpama North. During this time the mine experienced difficulty in building up and maintaining the targeted production rate. In an effort to ease the bottleneck on production long hole stoping with waste backfill was trialled. This method proved very successful at Mpama North and the mine currently uses this mining method.

The main difference between Mpama North and Mpama South is that the Mpama North orebody consists of a single mineralized zone of 5 to 10m wide. At Mpama South the orebody has been modelled as a number of roughly parallel vein type lodes of widths from 2.0 m to 15 m, and with a varying middling thickness between the veins.

Initial concerns were that the veins may be too narrow for the Mpama North type LHOS to be applied. In order to test this Mineable Shape Optimiser (MSO) software was used and various options of cut-off grade, and minimum mining width were investigated. The MSO process is discussed further in section 4.2 below.

The nature of the Mpama South orebody, with multiple veins type lodes approximately parallel to each other makes the manual stope design very onerous. The grade distribution within the lodes is variable along strike and dip, as are the width of the lodes and the waste middling between them. In order to select stope shapes in a complicated scenario such as this modern mine design software offers some solutions. A number of software providers offer a mineable shape optimiser solution. This program automatically selects the stope shapes based on a set of input criteria set by the user. The MSO module of Datamine Studio5® mine design software was used to generate stopes for the Mpama South orebody.

In the long hole open stoping method access onto a level, from the ramp, will be via an access cross cut. From the access cross cut mining drives will be developed in the mineralized zone to the extent of the mining block. The mining block will be split into stopes of a maximum span of 20 m long. This is based on the geotechnical design criteria which allows for a maximum of 20 m strike span and a vertical span of 15 m. Stopes will be separated by a rib pillar of 3.0m width.

The stopes are mined in a bottom up sequence. Once a stope has been mined and backfilled with waste rock, the stopes adjacent to it and the one above can be mined. Mining of two adjacent stopes simultaneously is not allowed due to safety concerns should a rib pillar fail.

The stope slot raises are developed by long hole blasting methods. Once the slot raise is complete the slot is opened up to the full width of the orebody, creating a mining face, from where stope blasting can commence, advancing back towards the stope access crosscut. At Mpama North the technique has been developed where a stope is pre-drilled and charged and then blasted in a single blast. If required safe entry can be gained into the stope on the upper level by driving on the blasted muckpile. If required stope support can be installed prior to mucking of the stope.

Stope blast hole drilling will be done by an electrohydraulic production drill rig drilling typically 76 mm diameter holes. Typically, one metre of blast hole will produce 5.0 tonnes of ore.

Based on the geotechnical report (Section 3) the level spacing was set at 15m. This is the level spacing prescribed for mining in the chlorite schist. Not all mining takes place in the chlorite schist but it is not practical to have different stope heights or level spacings across the orebody, so the minimum level spacing was selected.

Alphamin has been operating the Mpama North process plant since mine and plant commissioning in 2018. Several operational and capital projects have optimised and increased its performance and recoveries since it’ original design and construction. Under the PEA study conducted on the Mpama South development project, the intention was to construct an identical processing plant to the existing one. Only minor improvements to better treat the lower grade ore from Mpama South and modification to improve on identified inefficiencies in the existing plant will be included in the design of the Mpama South process plant, but in essence, the plant will be largely identical to Mpama North.

The Mpama North process plant has been designed to treat between 360ktpa and 430ktpa of RoM ore from the mining operation. This will generate in the order of 20ktpa of tin concentrate at a grade of >60% Sn. The Mpama South process plant although nearly identical will be designed to treat 480ktpa. Th ........