the client specifications due to the high
belt speed of 6.5 m/sec.
Manufacturing of all components
was accomplished by local suppliers in
South Africa and civil construction
began in early 2013. The overland
conveyor was produced in a
lightweight H-frame modular design
derived from the Thubelisha project,
while the civil base design consists of
two mini-piles with an extremely
lightweight precast sleeper weighing
in the region of 80 kg versus the 630 kg
of gravity sleepers. In combination,
these elements represent a design
innovation that optimises the timing of
the installation of the overland
conveyor.
In terms of environmental impact,
spillage was a major concern to the
client. The Sandvik Mining Systems
team addressed this by providing all
the transfer towers with bunded areas
that have a specific drying sump to
contain spillage. Specific attention in
this regard was given to the overland
conveyor, which crosses five
environmentally sensitive wetlands
and spans a river. At the river crossing,
the conveyor is elevated and sealed off
for a length of 800 m.
The design team also had to take
into account the noise generated by the
overland conveyor. A study to
determine the main causes of noise
generation associated with this
structure led to the use of HDPE rolls,
instead of steel idler rolls, to muffle the
noise as coal is conveyed past
farmhouses and informal settlements.
A decrease in the sound power level of
up to 4 dB can be expected.
Cold commissioning is scheduled
towards the end of 2015 and the date
of hot commissioning will be
determined by the coal supply from
the client.
Conclusion
These and other similar projects across
Africa provide a clear indication that
Sandvik Minings’ capabilities in
long‑distance curved and complex
overland conveyors are being
recognised in the marketplace. Its
in-house solutions and turnkey project
solutions are attracting increasing
attention throughout the continent.
Figure 3. Curved overland conveyor at Thubelisha.
Figure 2. 15 000 t surface bunker with tripper conveyors and trippers.
30
|
World Coal
|
July 2015
