PRODUCT News
50
MODERN MINING
June 2014
FLSmidth’s capabilities in the gold extrac-
tion arena will be showcased with the
supply of equipment to Vancouver-based
gold producer B2Gold’s Otjikoto gold
project. FLSmidth claims to be the only
company in Africa capable of providing a
complete end-to-end gold extraction solu-
tion drawn from in-house technology.
This know-how and equipment derives
from FLSmidth’s Summit Valley range of
modular plants and equipment for the
extraction of gold and silver. The Summit
Valley offering includes the industry’s
Otjikoto order to showcase FLSmidth’s gold expertise
highest capacity electrowinning cell used
in precious metals recovery.
The Otjikoto gold project is located
300 km north of Windhoek, Namibia,
between the towns of Otjiwarongo and
Otavi, and will rank as the country’s sec-
ond and biggest gold mine when it enters
production before year end.
The order was placed with FLSmidth in
the second quarter of 2013 and comprises
14 Krebs gMAX cyclones; four KC-QS48
Knelson concentrators reporting to a
ConSep Acacia CS8000 intense cyanida-
tion reactor; two 20 m diameter thickeners
(one pre-leach and one tailings) with a
bolted tank design; one carbon fines and
one sludge filter and four electrowinning
cells. FLSmidth will provide installation
and commissioning supervision on-site, as
well as post-commissioning support from
its Johannesburg operations.
FLSmidth’s gMAX cyclones focus on
minimising turbulence while maximising
tangential velocity, significantly advanc-
ing cyclone performance. To achieve these
two design criteria, the gMAX incorporates
performance enhancing improvements
to the inlet head, cylinder section, cones
and apex. The company’s Quantum Series
(QS) Knelson batch concentrator is highly
configurable and uses a rotating assembly
FLSmidth 20 m diameter thickener assembly
showing the bridge and feed well.
incorporating the latest design in concen-
trate cone technology and advancements
in the upper and lower frame.
“The low-grade Otjikoto ore contains
significant gravity gold that can occur
in relatively large nuggets, so maximum
gravity effort is planned for recovery, with
100 % of ball mill circulating load treated
by gravity,” says Dave Capstick, FLSmidth
Business Development Manager.
The Krebs cyclones, Knelson concentra-
tors and Acacia leach reactor were shipped
to the mine site in October last year fol-
lowed by the filters, with fabrication of the
thickeners complete and trial assembly
underway. The electrowinning cells and
standby units are about to be shipped.
Since FLSmidth acquired the Utah-
based precious metals extraction business
of Summit Valley five years ago, it has been
actively marketing these products in Africa
and achieving a steady penetration of this
market. These technology solutions are
directed at operating customers who are
planning to expand their gold recovery cir-
cuits and those who want to improve their
efficiencies, as well as those who are build-
ing new plants. There are also significant
applications where customers are experi-
encing operating inefficiencies.
Terence Osborn, FLSmidth, tel (+27 10) 210-4820
Hopper wagons designed for platinum belt
Despite continued labour unrest and
financial constraints in the South African
platinum belt, DCD Rolling Stock continues
to perform well in the region, having sold
a total of 33 discharge hopper wagons to
mining operations over the past five years.
Johannesburg-based DCD Rolling Stock
is a division of international manufacturing
and engineering company DCD Group, and
is recognised as a leading manufacturer
and supplier of locomotives, wagons and
bogies to railway, mining and industrial
operations.
DCD Rolling Stock’s Phillip van der
Westhuizen states that the company’s
side discharge hopper wagons are used
to transport ore from mine shafts to pro-
cessing plants for offloading. “Quality and
reliability have made our discharge hopper
wagons a trusted product in the region for
over 20 years.”
More recently, however, Van der
Westhuizen indicates that DCD Rolling
Stock has been working closely with plati-
num mine engineers over the past decade
in order to adjust the design of certain
discharge hopper wagons to adapt to con-
stantly evolving mechanical and safety
requirements.
“The latest discharge hopper wagons
are designed specifically for the South
African platinum belt, and feature a unique
safety mechanism on the side discharge
doors that prevents the doors from acci-
dentally opening in transit and causing
spillage, thereby improving mine safety,”
he explains.
The unique mechanism, known as a
‘central shaft over top dead centre lock-
ing device’, comprises three offset levers
connected to the doors with three links
per door. The levers have two end stops
to ensure that they rotate over the centre
position to prevent the doors from opening
accidentally.
Discharge hopper wagons weigh 85
tons with payload volumes of 26 m
3
, and
Van der Westhuizen reveals that spillage
can prove to be catastrophic. “For added
safety, the wagons also have a pneumati-
cally operated interlock featuring a cam
and hook that lock into place once the
doors are fully closed,” he says.
Van der Westhuizen states that the dis-
charge hopper wagon’s body and under
frame consist of a fully welded construc-
tion utilising S355JR steel, while the body
ends, centre gable and volume reducer are
angled to avoid any hang-up of ore during
unloading operations.
“The discharge hopper wagons are fit-
ted with high impact and wear resistant
body liners manufactured from Tivar GR12
material 20 mm thick on the body ends and
volume reducer, and 12 mm thick on the
lower half of the centre gable for improved
corrosion resistance. A combination of
vacuum and air brakes, each capable of
operating independently, adds to safety,”
he says.
Freedom Ndlovu, DCD, tel (+27 11) 306-8471
