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]