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July 2016
MODERN MINING
43
COUNTRY FOCUS
BOTSWANA
feature
A Cat 992G loads a Terex TR100 dump truck. The mining contractor at Karowe is MCC.
and which, collectively, are able to treat
approximately 415 t/h. A sixth Tomra machine
is on site but is used in an audit application on
the tailings stream.
Advantages of the XRT technology include
its compact footprint, low operating costs, high
recovery rates and extremely low concentrate
yields. There is no need to further process the
concentrate from the sorters before final hand
sorting. Day believes the Karowe installation
can claim to be the first in the world in terms
of primary diamond recovery although XRTs
have been used to treat recovery tailings in
some operations.
In his presentation in Gaborone, Day said
the LDR was able to recover diamonds of well
over 1 000 carats – as had been proven in the
case of the 1 111-carat stone. He said that
such was the success of the XRT installation
that Lucara had now embarked on a project
to increase the top size of diamonds recover-
able by the LDR and was also installing a new
Mega Diamond Recovery circuit to recover
large diamonds immediately post the primary
crusher. Both projects – which involve an esti-
mated investment of between US$15 million
and US$18 million – were in detailed engi-
neering design with the procurement of long
lead items in place, he said.
Updating delegates on Karowe’s performance
this year, Day said the mine had produced 165
diamonds larger than 10,8 carats at an average
stone size of 27,9 carats during the first quar-
ter. Of these, eight were larger than 100 carats
(compared to six in this range in Q1 2015).
Lucara’s guidance for 2016, he said, was for
revenues of US$200 to US$220 million (exclud-
ing the sale of the 813-carat diamond and the
possible sale of the 1 111-carat diamond). The
mine was expected to process between 2,2 Mt
and 2,4 Mt of ore over the year to produce
over 350 000 carats at an operating cash cost
of between US$33,50 and US$36,50 per tonne.
Finally and turning to exploration, Day
told delegates that Lucara – via Boteti – had
been awarded two precious stone prospecting
Boteti Mining personnel
in the Karowe pit. Current
mining operations are
concentrated on the central
and south lobes of the
AK6 kimberlite.