35 / 56
DIAMONDS
November 2016
MODERN MINING
33
State of-the-art plant under construction
The C-Cut project is not the only
major capital investment in prog-
ress at Cullinan. Petra Diamonds is
also in the process of replacing the
present sprawling treatment plant,
originally commissioned in 1947,
with a state-of-the-art processing
facility, which will have a compact
footprint, a high degree of energy
efficiency and feature modern
technologies – such as autogenous
milling – designed to increase dia-
mond liberation and minimise
breakage of the large gem-qual-
ity stones for which Cullinan is
celebrated.
The plant, which will deliver
a R20 to R25 saving per tonne in
processing costs, is expected to
be fully operational by the end of
Petra’s 2017 financial year. The
capex for the project is R1,65 bil-
lion with payback anticipated in
just three years.
advanced stage. The company also facilitated
the engineering for the Koepe winder upgrades.
The two winder upgrades were completed in
December 2014 and December 2015 respec-
tively, taking advantage of the holiday breaks
so as to minimise disruption to operations.
Murray & Roberts Cementation deployed
around 380 people on its contract at peak but
this has now reduced to about 60 people as the
contract draws to a close. Says Duyts: “This
has been a very successful contract from our
point of view and we’re very proud of the fact
that we’ve managed to meet all key dates and
maintain a safety record that is ahead of indus-
try norms. Factors contributing to our success
have included the excellent relationship we
developed with the Petra team and the inten-
sive planning we put into every stage of the
work. It also goes without saying that you need
to have the right people on the job and this was
certainly the case here.”
Commenting on the overall state of progress
on the C-Cut project, Cloete says the project is
running within schedule and budget. “The first
undercut rings were drilled and blasted during
June 2015 and the first draw bell drilled and
blasted during January this year,” he states. “In
terms of waste and blue (kimberlite) develop-
ment, we’ve completed approximately 22 km of
the nearly 27 km required. Of the total capital
budget of R4,2 billion, around R3,4 billion has
Draw point on the extrac-
tion level.
been spent – which is over 80 %. The first ore
from the C-Cut was delivered a year ago and
we’re expecting the project to contribute 1 Mt
of the total ROM production of 2,8 Mt planned
for our 2017 financial year, which runs to
30 June 2017.
“Full production will be achieved in
FY2019, by which time carat production will
have increased from 0,68 Mct/a currently to
around 2,2 Mct/a, with all of this – other than
about 200 000 carats from the reprocessing of
tailings dumps and around 120 000 carats from
the upper levels – being derived from C-Cut
ore. The project is transformational for Cullinan
and will ensure that the mine remains Petra’s
flagship for many years to come.”