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MODERN MINING
June 2015
MINING News
AIM-listed Stellar Diamonds recently
announced an operational update from
trial mining at its 75 %-owned, 5 ha Baoulé
kimberlite pipe in Guinea in West Africa.
The trial mining has yielded a total of
5 087 carats to date at an average grade of
13,5 cpht and high quality gems continue
to be recovered, including stones of 12,6
carat and 10,0 carat.
The first sale of 733 gem quality carats
from Baoulé in March realised US$195 000
for an average value of US$266 per carat
(which formed part of a larger sale of 4 414
carats). Included in this sale was a 5,55
carat stone which sold for US$5 000 per
carat and several stones which exceeded
Good progress reported on trial mining at Baoulé
US$1 000 per carat, underpinning the high
value and quality of some Baoulé gems.
Stellar Diamonds Chief Executive Karl
Smithson commented: “Good progress
continues to be made from trial mining at
Baoulé. Our objective is to produce 15 000
carats from this exercise to enable us to
determine the grade, value and presence
of large stones in the pipe, with a view to
using this information to consider a deci-
sion to advance Baoulé to commercial
scale mining.
“It is pleasing that we have achieved
our maiden revenues following the first
diamond sale from Baoulé, as well as other
Stellar projects. We are currently planning
Trial mining of the eastern lobe of the Baoulé kimberlite pipe (photo: Stellar Diamonds).
the next export and sale of Baoulé goods
and remain committed to targeting addi-
tional diamond sales throughout 2015.”
Trial mining of the eastern lobe of the
Baoulé kimberlite pipe has continued dur-
ing the first quarter of 2015. In order to
maximise the pit area in preparation for
the second 3 m cut, mining progressed
towards the eastern and southern margin
of the pipe where a lower grade contact
breccia was recently encountered, reduc-
ing the average grade to 13,5 cpht at a 1,25
mm cut off. This has resulted in fewer car-
ats being produced than anticipated at this
point in time, but mining and processing of
the second cut is expected to see a return
to higher grades, based on the results
realised from the first cut of the lobe.
Simultaneous to this mining, stripping
of the western lobe of the pipe has com-
menced in advance of the rainy season.
Overburden and ground disturbed by dia-
mond diggers is currently being stripped
to access the uncontaminated kimberlite
in preparation for bulk sampling.
The processing plant is running at a
steady state average capacity of approxi-
mately 50 t/h over a double shift (16 hours).
The kimberlite material remains predomi-
nantly weathered; however, some harder
blocks of kimberlite are being encoun-
tered. Since these blocks are too hard to
scrub but are also too soft to efficiently
crush, they are being sent to an oversize
stockpile where they are broken down
with an excavator prior to being re-fed into
the plant to ensure maximumdiamond lib-
eration and integrity of results.
BlueRock Diamonds commissions new plant
AIM-quoted BlueRock Diamonds reports
that the new plant at its Kareevlei project
in Northern Cape Province is now fully
operational and is in commercial produc-
tion processing at a rate of approximately
80 tonnes of kimberlite per hour.
“This is the culmination of almost 18
months of hard work during which we
have completed our trial mining and con-
structed our new processing plant,” says
Non-executive Chairman Paul Beck in the
company’s preliminary results for the year
ended 31 December 2014 (released on
19 May 2015).
“We were pleased with the results of
the trial mining from which we recovered
575 carats. These were sold at an average
price of US$248, some 36 % higher than
anticipated in the Competent Person’s
Report published at the time of our admis-
sion to AIM.”
Adds CEO Riaan Visser: “In December
2014, we halted processing of kimberlite
through the existing plant to allow con-
struction of the new plant to commence,
which included the addition of rotary pans
to the existing DMS plant and an enlarged
and more efficient crushing circuit. We are
confident that the new plant will enable us
to profitably produce sufficient diamonds
at a lower operating cost per tonne in 2015.
“We are yet to explore the remainder of
the Kareevlei property but based on the
sampling data received from the previous
owners, particularly for the K5 pipe, we
believe that it still offers excellent medium
to long term growth opportunities for the
company.”