On site
undertake mining in the area since 2004,
but none ever delivered on their promises,
until now. When African Mining
interviewed Viljoen last year, he was
adamant that the company will deliver
the goods and become a full-blown
mining company — and he delivered on
his promise of concentrate production
expected in quarter two of 2019.
How many pegmatites are there?
On site, Marais explains that pegmatites are
actually coarse-grained crystals and not a
rock type. At Uis, one can clearly see the tin
deposits within these pegmatites as Marais
points them out. “When we arrived on site
initially, we had to confirm that what we saw
was actually tin, as it doesn’t normally occur
in such coarse-grained deposits as with other
pegmatite-hosted tin deposits. We didn’t
require exploration drilling before making the
decision; it is all here at surface — you can
actually see the tin, coupled with a historical
resource produced by Iscor,” says Marais.
As we wind our way down through the
blasted debris into the V2 pit, the pegmatite
is visible everywhere on the big, open
exposed face in front of us, and the chances
are good that it continues underground.
“It is not a question of whether there are
pegmatites; the question is just how many
pegmatites there are,” says Marais. All the
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main open pits were developed by Iscor,
and since they left in the 1990s, there has
been no other large-scale mining in the
area. Iscor left almost overnight. A mapping
programme carried out last year delineated
an additional 180 unmined pegmatites
within 5km of the pilot plant.
The Uis pegmatites are 8m and 60m thick
at surface, which makes the Uis Mine one
of the largest (by volume) tin deposits in the
world, although the grades might not be as
significant as the majority of tin deposits that
are mostly 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.
Additional opportunities
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
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