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July 2016
MODERN MINING
41
feature
COUNTRY FOCUS
BOTSWANA
of big stones continues
Tomra XRT sorters in the
Large Diamond Recovery
(LDR) building.
A view of the processing plant area showing the LDR building (on the left) and the final recovery building.
geologically distinct, coalescing pipes that
taper with depth. With the north lobe now
having only limited reserves left (about 1 Mt,
which will be mined in Cut 2), current mining
operations are concentrated on the central and
south lobes.
The 1 111-carat diamond was the first of
the three to be recovered – by a 27-year old
trainee, Tiroyaone Mathaba. The news of the
‘find’ quickly went up the chain of command
at Karowe to the GM, Gerrie Ndlovu, who then
phoned Paul Day in Gaborone. As he recounted
to delegates to the conference, Day, in turn,
phoned Lamb, who is based in Vancouver.
Lamb was not immediately available – it was
in the middle of the night on Canada’s West
Coast – but returned Day’s call early in the
morning. Day told Lamb the momentous news
and congratulated him on being the CEO of the
first company in more than 100 years to have
recovered a plus-1 000 carat diamond.
Within another day (by which time Day
had flown to the mine), Karowe had produced
the 813-carat and 374-carat stones, prompting
Lamb to say in a statement that Lucara was
enjoying an amazing week and that the com-
pany was “truly blessed by this amazing asset.”
As Day pointed out to the delegates at the
conference, all three of the diamonds were
recovered in the mine’s innovative and pio-
neering Large Diamond Recovery (LDR) circuit
which was commissioned in May 2015 (as
part of a much larger US$55 million Phase 2
upgrade of the Karowe plant executed by DRA
on behalf of Boteti Mining). At the heart of the
LDR are five Tomra X-Ray Transmission (XRT)
sorters – able to identify the carbon signature
of diamonds – which replace conventional
DMS technology in the -60+80 mm size range