52 / 82
50
MODERN MINING
January 2015
DIAMONDS
Top projects
a formidable high US$/carat resource. The
mine plan is based on probable reserves of
33,1 Mt containing 5,1 million carats from an
open pit designed to 320 m depth. The indi-
cated resource from surface to a depth of 400 m
amounts to 48 Mt containing 7,6 million carats.
There is also an inferred resource from 400 m to
750 m of 21 Mt containing 3 million carats. The
deposit is open at depth.
The geologists describe AK6 as “a three-lobed
body primarily composed of volcanoclastic
kimberlite with lesser hypabyssal facies kim-
berlite.” The three lobes are referred to as the
North, Centre and South lobes, with the bulk of
the reserve (75 %) being contained in the South
Lobe. All the lobes are currently being mined
and the North Lobe, the initial focus of mining
operations, is over 60 %mined out. At the pres-
ent processing rate of approximately 2,5 Mt/a,
the open-pit mine life is around 13 years – with
the ultimate dimensions of the pit expected to
be 800 m x 700 m by 320 m.
Commenting on the performance of Karowe,
Paul Day – who joined Lucara as COO in
March 2013 and who was previously GM at the
Trekoppje uraniummine in Namibia (and before
that a senior manager with AngloGold Ashanti
in Mali) – says the mine has met Lucara’s
expectations, and more. “It was designed to
be roughly a 400 000 carats a year producer
and we are achieving this easily,” he says. “In
2013 we produced just over 440 000 carats and
our guidance for 2014 is between 400 000 and
420 000 carats at an operating cost of US$31 to
US$33 per tonne treated. But the really exciting
feature of Karowe is the sheer number of large
stones that have been recovered which is way
ahead of what Lucara expected when it com-
missioned the mine. For example, in the first
half of 2014 we recovered 547 diamonds larger
than 10,8 carats, including 67 larger than 50
carats and 25 larger than 100 carats.”
In fact, several stones have been above 200
carats, with the biggest to date being 281 carats.
Diamonds above 100 carats – and, even more
so, 200 carats – are extremely rare and, apart
from Karowe, the only other regular produc-
ers of stones this size in the Southern African
region – and indeed globally – are Letšeng in
Lesotho, owned by Gem Diamonds, and Petra’s
Cullinan mine near Pretoria. The value of
Karowe’s diamonds has also been greater than
originally anticipated, with the average price
achieved in H1 2014 being over US$750/ct
(including all the ‘specials’ above 10,8 ct).
Operationally, Karowe is run on an out-
sourced model, with contractors running the
main functions of open-pit mining operations
and ore processing. The mine is operated by
Lucara’s local subsidiary Boteti Mining headed
by MD Ribson Gabonowe. Day-to-day manage-
ment of the mine is in the hands of GM Gerry
Ndlovu and the total employee complement
he is responsible for (including contractors) is
around 800 people. He takes satisfaction from
the fact that his senior managers are mainly
Batswana with just one expat in the team.
Ndlovu is a metallurgist (he graduated
from Queen’s University in Kingston, Ontario,
Canada) and prior to joining Boteti Mining
in 2010 spent nearly 20 years with BCL in
Selebi-Phikwe.
He was Karowe’s third employee and has
seen the project move through from concept to
commissioning to operation. Like Day, he labels
it a “huge success” but says that a particular
focus at the moment is safety. “In 2012 we were
one of the best performing mines in Botswana
in terms of safety and received an award from
the Botswana Chamber of Mines,” he notes.
Above:
Aerial view of
the Karowe mine, which
is located in the Orapa
Kimberlite Field near the
town of Letlhakane.
Centre:
The pit at Karowe.
All the lobes are currently
being mined and the North
Lobe, the initial focus of
mining operations, is over
60 %mined out. Remaining
pit life is about 13 years
(photo: Arthur Tassell).