Mining in focus
between plants for inter-company
transit or product management.
Daniel van Vuuren,
mechanical engineer at
Loadcell Manufacturing and
Services t/a
Route Calibration
Why are weighbridges important
in the mining industry?
All products sold by weight need to
pass over a verified type-approved
weighbridge. Weight is directly
linked to sales, general business,
public safety, and wear and tear on
infrastructure — roads especially.
In mining, weighbridges enable
large-scale weighing with accurate
results and minimal interference with
the daily production of the mine, as
trucks can pass over weighbridges
quickly, allowing accurate tracing
of product or ore movement within
plants or sites.
How many weighbridges should
a mine install on its property and
where do these weighbridges
need to be constructed?
Depending on the operations and
the size of the site, weighbridges can
be installed at the main entrance
and exit gates of the site, with others
requiring more frequent weigh-ins
Some Mining Mirror readers are
junior miners currently developing
new mines. What advice would
you give them when it comes
to installing weighbridges?
For companies with an output of
more than 500t per month over
the weighbridge, a multi-deck
weighbridge with individual
weighing needs to be installed.
When buying a new weighbridge,
it is imperative to ensure that the
weighbridge you are getting is
definitely approved for trade by the
NRCS with a SA number, and that
all the parts are approved.
What do site preparation and
construction of weighbridges entail?
It entails mostly civil excavation.
Weighbridges should preferably be
placed on high-lying ground to prevent
the collection of water.
There are multiple phases in the
construction of a weighbridge. These
include the civils for the structure/
housing/location of the operator, as
well as instrumentation with software,
load receptor, loadcells, junction box,
and instrumentation.
How often does a mine need
to do maintenance work on its
weighbridges?
Depending on the operation and the
environment where the weighbridge
is located, a quarterly checking
schedule is recommended. Proactive
maintenance is always better than
reactive maintenance. This can be done
informally with a known mass, or
with a comparison mass that has been
weighed on another weighbridge. In
this way, any deviations from expected
weight can be logged and traced,
and problems identified before large
changes or issues with the weighbridge
occur. Apart from this, calibration
and verification of the weighbridge
at intervals recommended in their
type-approval documents are necessary.
This exercise should take place annually
or biennially. The information can be
accessed by contacting the NRCS to
request details on your weighbridge,
with the SA number as the reference.
What should a mining company do
to ensure that weighbridges are
kept in an optimum condition and to
maximise its operational life?
Proactive maintenance is the best
course of action. Furthermore, operators
need to ensure that the weighbridge
is clean and free of waste and damage.
It is important that all moveable parts
of the bridge are still floating (plates)
and that there are no obstructions or
exposed cables that could accidentally
be pulled out or damaged.
Name a few factors that could
damage or seriously affect the
efficiency of weighbridges.
Overloaded trucks using the
weighbridge cause severe damage. The
continuous use of air brakes on the
weighbridge could cause the plates to
shift from the loadcells, which results
in overloading the loadcells or breaking
their mounti