May 2014
MODERN MINING
27
LEAD-ZINC
vertical shaft will become primarily a vent
shaft. No waste will come to surface – it will all
go into underground voids which we believe
can accommodate about 750 000 tonnes.”
Claridge points out that the Karib Formation
host marble at the Namib mine is extremely
competent and that there are only a couple of
rock bolts in the existing workings. “We’re not
anticipating having to do any significant sup-
port work once we restart mining,” he says.
Turning to the plant, Claridge says that the
plant that was on site has been removed. “We’ll
put in a brand new plant which will be modular
in design and which shouldn’t take more than
about six months to build,” he states. “It will
probably encompass a single stage of crushing
using an impact crusher, screening, milling via
a single 450 kW ball mill, sequential flotation
of the lead and zinc, and final thickening. We
would then transport the concentrates – either
by road or rail – to Walvis Bay for export. The
plant will have a 250 000 t/a capacity but will
be designed to allow expansion.”
In respect of tailings disposal, French notes
that a new tailings dam was constructed in the
mid-1990s for a tailings reprocessing operation.
It was designed by Epoch and has a capacity of
1,5 Mt. “This is the beauty of this project,” he
says. “We have an underground mine in place
with very limited work to be done in order
to restart mining, as well as a tailings facility
which is ready for use. As a result, our capex is
going to be very low. The feasibility study will
give accurate figures but at this stage we think
we’re looking at an investment of only about
£15 million.”
The feasibility study – which is being under-
taken by Snowden, with Tenova handling the
plant design – was due for completion at the
end of April but has been delayed slightly – a
result of metallurgical testwork taking longer
than expected. It should now be released by
August, possibly sooner.
On site, infill and exploration drilling is con-
tinuing, using a Kempe U3-9B diamond drill
belonging to North River, as well as an Atlas
Copco 262 drill, which is operated by Shali
Drilling. The Kempe is currently working in a
300 m drive being developed under the north-
ern lodes of the orebody.
Drilling and mining contractor Shali, which
is run by Namibian businessman Wilhelm
Shali, is emerging as a fully fledged partner
of North River. The two companies signed a
‘drill-for-equity’ agreement earlier this year, in
terms of which Shali will be paid in shares of
North River rather than cash for the drilling it
undertakes. The agreement was established to
cover the first £175 000 worth of invoicing for
drilling activities and shares are being issued
at an equivalent of 0,6 pence each for works
invoiced.
The latest resource figures for the Namib
property were released in December 2013 and
show a 129 % increase in the overall resource
to 1,57 Mt. This is made up of 917 000 tonnes
(indicated) of fresh ore at 2,4 % Pb, 5,7 % Zn
and 44,8 g/t Ag and 610 000 tonnes of tailings
(measured and indicated) at 0,3 % Pb, 2,1 %
Zn and 7,6 g/t Ag. These figures give an in-situ
metal inventory of 23 700 tonnes of lead, 65 500
tonnes of zinc and 1,48 Moz of silver.
“The orebody at the mine is open at depth
and the exploration drive we’re developing will
allow us to assess the potential for deep ore at
Namib. In addition, we had a new exploration
licence granted last year which has expanded
the near mine exploration area by over
12 000 ha to give us a total exploration area of
nearly 17 000 ha. The area has numerous sur-
face gossans that are similar in size to the one
that led to the discovery of the Namib mine so
there is clearly considerable exploration upside
for the project,” French concludes.
The newmine is being
developed in an area
with excellent transport
infrastructure. This rail line,
for example, traverses the
property.
North River personnel
working in the field at the
Namib project.
