AFRICA NEWS
minimise such climactic effects by
cutting and crushing the material with
a special cutting drum and placing it
alongside the machine (sidecasting),
ensuring constant productivity while
minimising the environmental impact.
The use of a surface miner also has a
positive effect on water management in
an opencast mine. The cut surfaces are
levelled and can be cut at an angle. This
further improves drainage and reduces
water seepage into the ground.
Sidecasting and haulage: More tons
per hour
During side-casting, Wirtgen surface
miners leave high stockpiles, allowing
a superb bucket fill. This protects most
of the mined material from the rain and
allows gravity to drain the piles. The
major cost factor in opencast mining is
haulage. Mining with Wirtgen surface
miners produces level surfaces that
serve as stable roadways, supporting
the rapid transport of material. This
increases the transport capacity of
the entire truck fleet. Even the wear
on tyres, frame, and suspension is
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reduced thanks to the quality of the
roadways, also allowing the use of
standard on-highway trucks. As a result,
reduced transportation costs allow
mining companies to achieve lower per-
ton production costs.
Mine operators benefit from several
cost reductions when using surface
miners. Dr Ing Erik Zimmermann,
product manager for surface miners at
Wirtgen, explains: “Our machines allow
efficient extraction of material from
mines that could not be economically
exploited with traditional techniques,
creating added value for the industry.
For the mining companies, this
translates into significant financial
advantages for mining and processing.”
Avoiding blasting, avoiding hazards
By using surface miners instead of
drilling and blasting, raw materials
can also be extracted effectively
in the vicinity of residential areas,
public roads, villages, rivers, or other
infrastructure, for example pipelines
or power lines. It is also possible to
mine resources located in buffer and
safety zones, maximising bauxite yield
within the concession area, generating
significant additional revenue for the
mine.
In most cases, the planning and
execution of blasting operations is
associated with considerable effort,
high costs, and regulatory restrictions.
In fact, eliminating drilling and blasting
relieves the people responsible of a
number of challenges. The Guinean
mine operators using surface miners
no longer need to spend time obtaining
the required permits, hiring certified
blasting personnel, or compiling the
relevant documentation. What is more,
dispensing with drilling and blasting
has a very positive impact on public
opinion, meaning that opencast mining
operations can gain wider acceptance.
In addition, Wirtgen machines enable
mining companies to improve material
quality. The material size produced
by these surface miners is ideal for
shipment by truck and rail, eliminating
the use of the primary crushers
commonly used when drilling and
blasting.
APRIL 2019
7