On site
Black tin spots dot the pegmatite in and around Uis.
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 size and has returned high
recoveries,” says Marais.
A question of water
Uis is in an extremely dry environment
(the area is classified as a desert) and the
availability of water is always a concern.
However, according to Johan van der
Westhuizen, resident engineer for phase
one of the AfriTin project, there is more
than enough water available. “We have
drilled eight holes and we found water in all
of them. There is more than enough water
available for the processing plant during
phase one,” says Van der Westhuizen.
“Phase two is a bigger operation but
we hope to use all the knowledge and
26 AFRICAN MINING MAY - JUNE 2019
information we gathered in phase one, and
duplicate it in the next phase,” he adds.
When Iscor mined the Uis deposit, they
sourced most of their water from the
pump station at Omaruru, about 64km to
the east. That capacity still exists, but Van
der Westhuizen says the pipelines are in
need of an upgrade. “In addition, we have
appointed a hydrologist to investigate
developing an additional well field close
to the pumping scheme, which AfriTin
will then develop in partnership with the
Namibian Department of Water Affairs.
There are a number of possibilities; the
source at the Ugab River can also be
tapped into [as] that water is not utilised
for anything at the moment,” says Van der
Westhuizen.
AfriTin is also exploring the opportunity
of tapping into the biggest desalination
plant in southern Africa, which is
currently operated by Areva and is
relatively close to the plant.
AfriTin has acquired a thickener to recover
water from the tailings to ensure they recover as
much of the process water as possible. “Water
is a scarce commodity in this area, and we will
have to look at the re-use and preservation of
water very closely,” says Van der Westhuizen.
“We will have extremely good water recoveries,
so the tailings are really like dry sand by the time
it exits the plant,” Marais adds.
Acquisition a positive step
AfriTin recently acquired local company
Tantalum Investment. The deal includes
two exploration licenses at Brandberg
West and in the Goantagab Belt, which
is believed to hold substantial deposits
of tin, tantalum, and other associated
minerals, including lithium.
Viljoen says the acquisition of Tantalum
Investment is another positive step
for AfriTin in attaining their goal to
consolidate African tin assets and embark
on a regional expansion drive in Namibia.
“During a recent exploration programme
on our new licences and in the
surrounding area, we identified a number
of anomalous geological targets. Some of
these targets had been mined in the past
and we therefore believe in the overall
potential of the Damaraland area, in
Namibia,” says Viljoen.
“Our recent acquisitions are no more
than 80km away from our flagship Uis tin
mine and are therefore located in what
was once a prolific tin-producing region.
While bringing the Uis Mine back into
production remains our primary focus,
we will begin early stage exploration on
these new licences, with the objective of
reopening the whole region as a major tin
province,” Viljoen concludes. b
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