Modern Quarrying April-May 2017

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April - May 2017 MODERN QUARRYING 39
Revolutionary Wirtgen
surface miner
The Wirtgen Group, global leader in
mobile machine solutions for road con-
struction and rehabilitation, as well as
mining and mineral processing, has
recently conducted several large-scale
field tests on material degradation.
Findings confirm that Wirtgen surface
miners offer significant advantages in the
reduction of contamination experienced
in normal open cast mining methods.
In the coal mining industry, the
breakage of coal occurs throughout
production, from extraction at the face
to end use. While some of this breakage
is intentional, such as during extraction
and crushing, breakage occurring during
transportation, stockpiling, sizing or
washing is not desired. Generally speak-
ing, breakage behaviour depends heav-
ily on geology, but mining technology
of today offers the option to reduce the
amount of fines generated during pro-
duction to maximise coal recovery for
optimised operation as well as minimising
contamination of mined coal to increase
yields.
In an effort to serve its customers
better, Wirtgen recently conducted a
number of large-scale field tests on mate-
rial degradation. The company found
that its surface miners offer significant
advantages when it comes to minimising
contamination by selectively mining coal
seams to separate the ore from the waste.
A Wirtgen surface miner is a crawl-
er-mounted mining machine with a rotat-
ing cutting drum for rock penetration
mounted at the centre of gravity, a config-
uration that ensures that the full weight
of the miner machine can be transformed
into rock penetration force. The cutting
drum transfers the material onto a con-
veyor belt from which it is directly loaded
onto a dump truck.
The machine mines layer by layer
down to the required depth and the
cutting depth can vary according to
seam thickness. Even thin seams of just
10 cm thick can be mined and precisely
separated from the layers above and
below. This level of precision makes for a
cost-effective and more environmentally
sensitive approach to mining of mineral
deposits without any drilling or blasting..
The Wirtgen surface mining concept
is no longer an unknown in the southern
African mining sector. Surface mining has
proven to be a viable alternative in South
African open-cast mines, most especially
in coal mines, where these machines
really prove their worth. Wirtgen surface
miners are set to revolutionise the open-
cast mining industry in southern Africa, as
it has done across the world, by address-
ing the need for safer, more environ-
mentally friendly, effective and efficient
mining by improving yields.