Mining in focus
SepFluor’s Nokeng fluorspar mine boasts a
unique flotation system, writes Leon Louw.
T
he Nokeng fluorspar mine,
close to Rust de Winter
in Gauteng, is nearing
completion. The R1.7-billion project,
which includes the development of
two opencast mines, a processing
plant, and a concentrator, is almost
70% complete. Mining Mirror
visited the site recently for the
official opening of a new, on-site
training centre and got a glimpse of
construction work at the mine and
processing facility.
The event was attended by the
South African Minister of Mineral
Resources Gwede Mantashe, who
lauded SepFluor’s efforts in creating
jobs and empowering the youth
through providing practical artisanal
training. In his keynote address,
Mantashe lambasted the mainstream
media for not attending events that
tell a positive story about the South
African mining industry. Mantashe
said that Nokeng is a significant
project, being the first new mine to
be developed in Gauteng in the past
12 years.
According to Rob Wagner,
SepFluor CEO, construction at
Nokeng is on time and within
budget, adding that first production is
expected in February 2019.
Nokeng has a 12 million tonnes
(Mt), SAMREC-compliant reserve
and an estimated 19-year life-of-
mine. About 630 000 tonnes (t) of
ore containing ~27% calcium fluoride
will be mined annually from surface
and near-surface, initially from two
deposits.
About 180 000 tonnes a year of
acid grade fluorspar and 30 000
tonnes a year of metallurgical grade
fluorspar will be produced from the
mine’s state of the art concentrator.
There are not many other operating
fluorspar mines in South Africa,
with Nokeng’s neighbour, Vergenoeg,
being the most significant. Vergenoeg
is jointly owned by Spanish fluorspar
producer Minerales y Productos
Derivados SA (Minersa) with an 85%
www.miningmirror.co.za
share, and MEDU Capital (15%).
The mine has a production capacity of
240 000 tonnes per annum (tpa).
Upgrading fluorspar
According to Johan Brits, project
director at SepFluor, the Nokeng
project revolves around mining and
upgrading fluorspar. Fluorspar is
the commercial name for calcium
fluorite, which is an industrial
mineral that has multiple uses in our
everyday lives. Nokeng has two ore
bodies, Plattekop and Outwash Fan,
which will be mined as two different
open pits. The ore is drilled, blasted,
loaded, and hauled from the pits
to the mineral processing facility,
which is currently being constructed.
Construction of the plant got under
way on 9 June 2017 and is well
advanced. According to Brits, the
initial steps in the commissioning
started in the first week of September,
and installation and commissioning is
planned to be completed by February
2019.
“We have appointed a joint
venture between Group Five and
DRA to construct the plant, and
they are doing it on an engineering,
procurement and construction
(EPC) basis; in other words, they are
responsible for the design, supply,
construction, and commissioning,”
Brits explains.
The processing cycle at Nokeng
starts with primary crushing
(jaw-crusher), followed by
secondary crushing (cone-crusher).
High-pressure grinding rolls
(HPGR) are used in the third step,
which reduces the ore to minus
6mm. Then the material is fed
into a primary mill, which reduces
the size further to 150 microns.
The separation process involves an
oxide float rather than a sulphite
float, which is normally used in
conventional flotation in the gold,
platinum, and base metal industries.
The flotation process at Nokeng uses
specific chemicals and reagents, and
NOVEMBER 2018 MINING MIRROR
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