Tailings storage facilities are the largest
consumers of water on South African mines.
mining company will be employing filtration
to treat as much as half of its tailings output,
producing some 100 000 tonnes per month of
filtered ‘dry’ tailings. So, this sort of solution
is by no means unaffordable, although the
industry must certainly get to grips with the
substantial costs involved and build these
effectively into project viability costings.
The fact is that there is a growing push
to address water security alongside a range
of environmental imperatives, and mines
are required to take these very seriously to
safeguard the sustainability of any new mine
developments or expansions. There is already
a realisation among certain of our clients that
filtration technology will play an increasing
important role in projects they are currently
working on.
Another important benefit of filtered
tailings is its impact on the closure costs,
timelines, and responsibilities that are legally
carried by mining companies. It should be
remembered that wet tailings dams could
take anything from 20 to 100 years to dry out,
even with under-drains (depending on their
size and various other conditions). Taking
advantage of filtration allows this time goal
to be achieved immediately, resolving a range
of post-closure rehabilitation responsibilities
such as dealing with seepage water. While
the upfront cost of filtration may seem high
initially, there are considerable savings and
risk reduction further down the line.
Indeed, most mining companies are
increasingly concerned about the long-term
liabilities potentially created by their mining
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About the author
operations, and so any strategies that remove
or resolve these liabilities sooner rather than
later need to be seriously considered. The
question is often not just about the cost of
the early solution — a more pressing concern
may be related to whether the required skills
and teams will be on hand to diligently deal
with long-term obligations to the standard
that compliance requires. The widespread
commitment of the mining sector to best
international practice in sustainability
and environmental management would
certainly suggest that we are likely to see
more concerted application of technologies
previously considered very costly. Filtration
has various positive impacts that include
safety, risk reduction, and cost-savings.
The placement of filtered or dry tailings, for
example, can make for more manageable and
safer tailings facilities; safety in TSF design
and management is a topic I shall address in
the next article in this three-part series.
Returning to our specific concern with
water security, it is clear that bold science-
based strategies are the only way forward.
Water is a scarce natural resource and the
ongoing evolution of ethical behaviour as
an industry, demands that we minimise our
consumption of these resources with all the
technology at our disposal.
The article is the first in a series of three on
“Tailings dam technology: learning from
failure”.
Adriaan Meintjes is principal civil geotechnical
engineer at SRK Consulting South Africa.
Adriaan has been involved in civil and
geotechnical engineering for over three
decades and has worked for SRK Consulting
South Africa since 1992. His speciality areas
include soil and rock mechanics, numerical
modelling, foundation design, water and
tailings dams, and risk assessment.
SRK Consulting is a global network of
engineers and scientists. Much of its early
reputation was earned from its work on tailings
storage facilities and working closely with
mining companies to develop science-based
innovations to make tailings dams safer and
more environmentally sound. Today, SRK is
a multidisciplinary operation with a depth of
expertise relevant to mining, infrastructure,
environment, energy, and water.
Mining in focus
Adriaan Meintjes, principal civil geotechnical
engineer at SRK Consulting South Africa.
FEBRUARY 2019 MINING MIRROR [41]