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January 2015
MODERN MINING
51
DIAMONDS
Top projects
Lucara – based in Canada but rooted in Africa
Although it can trace its antecedents back to the 1980s, Lucara in its present
form was founded in 2007, with its first CEO – and now Chairman – being
Lukas Lundin. The present President and CEO, William Lamb, a South Afri-
can-trained metallurgist, joined the company as GM in 2008 (he was previ-
ously Process Manager at De Beers’Victor mine in Canada).
Lucara is listed on the Toronto Stock Exchange, Nasdaq OMX Stockholm
and the Botswana Stock Exchange and has its corporate office – very lightly
staffed – in Vancouver. The company’s focus, however, is entirely in Africa
at present and it maintains an office in Gaborone where COO Paul Day and
Ribson Gabonowe, MD of Boteti Mining, Lucara’s subsidiary in Botswana,
are based.
Above:
Kalcon machines
working in the Karowe
pit. By the time this article
is in print, MCC will have
taken over as the mining
contractor (photo: Arthur
Tassell).
“Since then we have experienced three LTIs, all
of them minor in nature. Nevertheless, we view
them seriously and we are currently putting an
enormous effort into safety, with the emphasis
on internalising safety behavior. Overall our
safety performance, though, is creditable and
thankfully we have never had a fatality.”
When
Modern Mining
was at Karowe late
last year the mining contractor in place was
Kalcon (part of WBHO), which was operating
a fleet of 36 Cat 730 and Cat 740 ADTs, work-
ing in conjunction with Cat 345, Cat 374 and
Cat 390 excavators. The mining operation
was explained to
Modern Mining
by Mining
Manager Joe Mchive, who said that the pit
would produce around 3,8 Mt of ore and 11 Mt
of waste by year end. He noted that stripping
levels would steadily increase as work started
on Cut 2, with the intention of exposing ore by
2018. He also said that Kalcon’s three-year con-
tract was drawing to a close and that – based
on the results of an open tender – it would
be replaced by MCC as from January 2015.
MCC’s contract is for six years and the com-
pany will be deploying a fleet which includes
100-ton rigid trucks for waste and 40-t ADTs
for ore, with the largest excavator being a 150-t
Liebherr machine.
The EPCM contractor during the initial con-
struction of Karowe was DRA and Minopex,
also part of the DRA Group, has an SLA (ser-
vice level agreement) contract to operate and
maintain the process plant. The current flow-
sheet is fairly simple and consists of primary
crushed ROM being processed through a sin-
gle autogenous grinding (AG) mill with the
+35 mm product crushed in a single pebble
crusher and recirculated back to the mill and
the +1,5, -35 mm mill product being processed
through a DMS with final recovery using
DEBTECH X-ray sorting machines.
According to Paul Day, the current modi-
fications to the plant – which are budgeted at
US$55 million and which are scheduled to
be completed in Q2 2015 – are intended to
optimise operations and allow the facility to
maintain throughput at 2,5 Mt/a as the orebody
at depth is mined. “The plant in its present
configuration was designed around treating the
near surface material, which is weathered and
transitional ore,” he explains. “It was always
understood that it would have to be modified
to handle the harder unweathered ore present
at depth – in the South Lobe in particular. Quite
apart from the need for increased comminution
capacity, it was also understood that the char-
acteristics of the ore change as we go deeper,
with the near density material (material with
a density close to that of diamond) steadily
increasing. This, in turn, results in the DMS cir-
cuit becoming less effective, and this is another
issue we’re addressing with the upgrade.
“What was not originally realised when
the plant was designed is that Karowe would
become a prolific producer of large stones. It
was only in 2013 that we started to recover