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MODERN MINING
October 2015
MINING News
London-listed gold miner Acacia, which
operates three mines in Tanzania, has
reported a lower than expected output
of approximately 164 000 ounces for the
quarter ended 30 September 2015. It
attributes this to several short-term fac-
tors negatively impacting output at the
Bulyanhulu and Buzwagi mines over the
period. The North Mara mine performed in
line with expectations.
As a result of the lower levels of pro-
duction, cash cost per ounce sold and
all-in sustaining cost per ounce sold (AISC)
for the quarter will be above US$800 per
ounce and US$1 200 per ounce respec-
tively. Acacia predicts, however, a stronger
fourth quarter performance, with produc-
tion increases at all three mines.
With the increase in fourth quarter pro-
duction, the company expects to deliver
full year production at around the level
achieved in 2014 (718 851 ounces), com-
pared to the initial guidance range of
750 000-800 000 ounces.
Commenting on the update, Brad
Gordon, CEO of Acacia, said: “I am person-
ally very disappointed in the operational
performance in the third quarter, which
saw a succession of small issues impact
Buzwagi and the ramp up at Bulyanhulu.
We have addressed each of these to ensure
they do not impact future performance.
Importantly, key underlying metrics at
Bulyanhulu, such as underground devel-
opment rates, mining widths and stope
availability are on track to sustain a step-
up in production in Q4 2015.”
At Bulyanhulu, the anticipated pro-
duction ramp up did not materialise
during the quarter, leading to production
of approximately 62 000 ounces, with run-
of-mine production of 55 000 ounces and
reclaimed tailings production of 7 000
ounces. The reduced output was primarily
due to delays in opening new high grade
long-hole stopes, which led to lower ore
tonnes mined than planned and reduced
head grade together with lower plant
recoveries. A specialist contractor has been
brought in to undertake the stope opening
Acacia production lower than expected in September quarter
Bulyanhulu – which was commissioned in 2001 – is an underground mine with shaft access, which is
transitioning to long-hole and drift and fill as its principal mining methods (photo: Acacia).
Acacia’s Buzwagi mine is a low grade bulk deposit with a single large open pit. The process plant is designed with
a throughput capacity of 12 000 tonnes of ore per day (photo: Acacia).
process, which will ensure that sufficient
long-hole stopes are available as the mine
moves into Q4 2015.
Recoveries have been impacted by the
lower grade together with instability in the
plant caused by power interruptions and
contamination of the elution circuit, which
have both now largely been resolved.
Furthermore, in order to better manage
long term recoveries and processing costs,
the mine is looking at options to separate
the run of mine and the reclaimed tailings
streams within the CIL circuit.
At Buzwagi, production of approxi-
mately 34 000 ounces for the quarter was
impacted by the mining of lower than
planned grades together with reduced
mill throughput as a result of extended
crusher downtime in September and an
unplanned SAG mill re-line. Mining during
the quarter was primarily focused on lower
grade splay areas within the open pit;
however, negative grade reconciliations
from a higher grade zone, combined with
limited flexibility resulting from slower
than planned waste movement, led to
mining below reserve grade for the quar-
ter. The mine focused on additional waste
movement in late September which will
continue into early Q4 2015.
At North Mara, production of approxi-
mately 68 000 ounces was in line with plan.
As expected, mined grade from the under-
ground operation increased. This was due
to the proportion of stoping ore of total
underground ore production increasing
over the quarter, and Acacia expects this
trend to continue into the fourth quarter.