Mining in focus
A 2006 tailings dam model.
there is now a new requirement for both
undrained and effective stress analyses — also
considering real-time modelling of behaviour
of the tailings facilities. Increasingly detailed
investigations and testing — from both the
field and in laboratories — are required,
to better understand tailings dam material
property behaviour. The testing results are then
used to model, including seepage behaviour,
consolidation behaviour, compressibility
behaviour, shear strength behaviour (static
and dynamic conditions), static liquefaction
behaviour, and tailings deformation behaviour
under seismic conditions.
Many appropriate developments and
advances in modelling software are currently
being made as computing power becomes
increasingly more affordable; for example, fully
coupled seepage, consolidation and (static and
dynamic) stress modelling is now possible. A
step change in these engineering tools should
become more user-friendly and affordable
within the next decade.
Waste management
critical
Water management on and off the facilities
is also becoming more critical. At many
mines, there is a requirement to co-dispose of
mining waste streams — sometimes from the
process plants and sometimes from mining
and plants. This can lead to complex residue
www.miningmirror.co.za
Many design innovations are required to
provide safe storage facilities, considering
waste stream material incompatibilities from a
material behavioural point of view.
storage design, and no single solution fits all
construction and operating requirements.
Many design innovations are required to
provide safe storage facilities, considering
waste stream material incompatibilities from a
material behavioural point of view. However,
many site-specific innovations have been
achieved by SRK. We have also been able to
assist clients in reducing costs by additional
optimisations.
The use of HDPE-type liners as barrier
systems has a major effect on the stability
behaviour of tailings dams, as above and
below liner drainage systems have to be
provided, and the design criteria for both
cases are still in a process of development
and evolution. The design of monitoring
systems is likely to undergo considerable
development — in the past, the practice was
to provide for instrumentation such as stand
pipe piezometers and drain flows, which could
be read on a weekly or monthly basis. A recent
development is to install instrumentation that
can be read on a real-time basis — and making
use of satellite technologies will become
common within the next decade.
Considering the mining sector’s heightened
concern with safety regarding TSFs — and
the potential for technology to gather and
analyse ever-larger quantities of real-time
data — the scope for engineering even safer
tailings dam solutions is within our grasp. It
is exciting to know that the questions that
mines are now asking about TSFs can and
will be answered.
MARCH 2019 MINING MIRROR [21]