WATER
Water is a scarce resource in South Africa, and
the effective management thereof is essential for
the sustainability of a quarrying operation.
Commonly used water management techniques.
The efficient use of water in a quarry focuses
on recovering or capturing it from rainfall,
run-off, and groundwater ingress so that it
can be used for on-site activities, instead of
using costly treated water from municipal
sources. The size, nature, and function of
storage facilities therefore need to be carefully
planned, constructed, and monitored
in line with predicted water inflow and
consumption levels.
While most quarries do not have to deal
with the waterborne chemicals commonly
used in mines’ pro cess plants, there are still
significant levels of suspended material
in water on site — as well as potential
contaminants from explosives detonated
during blasting operations. The use of water
to wash silt out of quarry sand or aggregate is
another common cause of contamination.
Impact of lining
Settling ponds remain an important stage
in the treatment process, but environmental
regulations now require settling ponds to
be lined with a geomembrane to prevent
seepage of contaminated water. This also has
implications for water management: As less
seepage means more water on surface; at the
same time, this creates an opportunity for
quarries to become more water efficient by
recycling greater quantities of this resource for
on-site use.
To achieve the necessary levels of quality,
however, further stages of mechanical or
even chemical cleaning may be required.
This inevitably requires an investment in
the necessary infrastructure, whether this be
in the form of equipment like cyclones or
other mineral separation technologies, or in
need to be systematic in the way that they
control their usage.
Quarries, like mines, will all have
their own specific challenges when
it comes to managing their water
supply, but generally, it comes down
to controlling the water balance. This
means ensuring that the quantities
entering the system are aligned with the
amounts leaving it — avoiding shortages
on the one hand, and dangerous
spillages on the other.
QUARRY SA | JULY/AUGUST 2018 _ 29