Mining Mirror May 2019 | Page 19

Mine excursion underground. The belt continues for at least another 3km to the south and is open at depth, according to Marais. Mining consultant SRK compiled a historical resource of the Iscor mine and found that the V2 pit constituted about 55% of the contained tin. This particular pit had a maximum stripping ratio of four. The combined bench height in V2 is about 50m at the highest point. According to Marais, there are 16 historical pits in the area that were developed by Iscor. “We have already delineated 180 pegmatites, which are exposed at surface, within 5km of the pilot plant, of which 95% contained visible tin mineralisation. V5/V12 were two separate pegmatites at surface but become one at depth; V5 three-metre-thick outcrop when initially mapped but is now 12m thick where it is exposed in the bottom of the pit,” explains Marais. More opportunities at the footprint Coarse-grained pegmatites are abundant in the Uis region. The entire footprint where the open pits were developed, stretches for about 5km, but Marais says that AfriTin’s mining licenses continue much further. So, what are the chances of finding more significant tin deposits? “Well, the chances are extremely good. We recently drilled a waterhole and intersected a pegmatite at a depth of 14m that turned out to be >60m thick. All the artisanal activity is another indication that there is a lot of tin still to be found. We recently undertook a detailed mapping exercise over the V1 and V2 pits, as we have identified it as a priority target. The detailed mapping indicated that the V1 pegmatite is significantly thicker than we originally thought,” says Marais. AfriTin also acquired the historical Iscor data, which provided a plethora of useful information. A total of 149 complete drill holes were acquired for the V1 and V2 pegmatites; additionally, the data indicates that the V1 and V2 pegmatites widen and intersect at depth. According to the old SRK reports, the average grade for the V1 and V2 pits is about 0.14% tin (Sn). The tin is associated with secondary tantalum and niobium, and Marais says there is real potential for lithium (partially mentioned elsewhere), but that they will evaluate it with the current exploration programme. The access ramp will enter V1, and the processing plant is about 300m from the pit. In addition, they expect there to be no milling and high recoverability, limiting the effect of a lower grade with a preconcentration phase in the plant. The pilot plant, part of phase one, will treat about 60 tonnes per hour and the tonnages will increase as the plant expands. “We will be using dense media separation (DMS) in the recovery process, instead of a jig, which has proven to be very efficient over a larger grain The pegmatite belt stretches for about 3km before it disappears underground. www.miningmirror.co.za MAY 2019 MINING MIRROR [17]