VALUE FROM OLD MINES
International Mining’s Insight Series of videos,
Liam MacNamara, FLSmidth VP Sales, addresses
some of the key questions in this subject area
including outlining some recent innovations –
https://im-mining.com/interviews/mine-tailings-
management/
FLSmidth’s millMAX-e™ pump is a high
efficiency slurry pump designed to maximise
efficiency and minimise cost of ownership.
This is a further optimisation of the world-
renowned millMAX design for slurry
applications. The hydraulically advanced
impeller and an extremely efficient design, gives
users a maintenance friendly pump that will
often enable downsizing of the drive motor,
“thus further minimising cost while maximising
efficiency,” the company says.
“With a low upfront cost and increased power
savings, the millMAX-e can pay for itself in less
than a year of operation.”
Evaluating potential
When excavating old dumps, wheel loaders and
trucks are a popular method. Otherwise, water
monitors to break down the dumps and slurry
the material are commonly used in South Africa
and elsewhere
Phase 2 envisages the construction of a high-
volume central processing plant capable of
processing at least 1 Mt/mth and the
development of a new regional tailings storage
facility. In this phase, reclamation will be from
the Driefontein 3, Libanon and Kloof 1 dumps
initially and then from the Ventersdorp North
and South dumps.
Phase 2, Pretorius says “will provide a
compelling advantage insofar as future regional
consolidation is required” – meaning the scale
of the infrastructure established would allow for
reclamation from other sources in the region.
As an alternative to Phase 2, or in the event
that Phase 2 is delayed, Phase 1 will be capable
of extension by blending in material from the
Driefontein 3 dump. It envisages the treatment
of 77.7 Mt from the Driefontein 3 and 5 dumps
and a further upgrade of the Driefontein 4
tailings dam. The estimated NPV of the
alternative option is ZAR2.7 billion, assuming a
capital outlay ZAof R397 million in addition to
the initial Phase 1 capital outlay.
DRDGOLD estimates the NPV of the entire
WRTRP at ZAR2.1 billion.
Tailings management
Whether tailings are being reclaimed or not,
their management has always been a challenge
in terms of first handling the volumes of
material and secondly ensuring environmental
safety. The technology exists in the form of
thickened and paste tailings and associated
48 International Mining | MAY 2018
equipment to make tailings management much
safer and more efficient; and the industry is now
finally taking steps to move away from wet
tailings impoundments where possible.
FLSmidth is at the
forefront of working with
mining customers on
these system
designs and
technologies – in
the first of
Like all the pumps in the millMAX family,
FLSmidth’s millMAX-e pump includes the
patented millMAX Suction Side Sealing System.
This reduces wear by maintaining initial
clearances within the pump to reduce internal
recirculation and eliminate solids grinding
between the impeller and suction side.
Adjustment can be made while the pump is in
operation. The result achieves a constant flow
and pressure, without having to speed up the
pump. This extends the life of all wet end parts
and reduces power consumption. There is wide
clearance between the impeller and suction
side. The adjusting screw lock nut compresses
the wear ring carrier to provide a seal to
atmosphere and lock the jacking screw in place
Gekko and CSIRO are partnering to
commercialise a new technology that will be
very useful in evaluating the potential of tailings
and other solution streams to yield economic
value or in the monitoring of recovery plants. It
provides real-time analysis for gold content in a
slurry or stream, delivering an updated sub-
parts per million (ppm) Au measurement every
10 minutes. The OnLine Gold Analyser (OLGA)
provides analysis and insights into process
performance that are unobtainable with assayed
sample sets. While traditionally assayed
samples consist of homogenised samples that
are collected and then delayed up to 12 hours
by lengthy processing, OLGA provides live data.
This enables real time monitoring and
adjustment of process systems and empowers
mining operators to minimise gold losses from
process excursions.
Complimenting Gekko’s existing Carbon Scout
measurement system, OLGA will enhance
Gekko’s metallurgical accounting system which
is currently under development in collaboration
with Rockwell Automation.
OLGA is specifically designed to enable direct
measurement of gold in tailings, feed and
concentrate slurries streams down to sub-ppm
levels, unlike conventional X-ray fluorescence
(XRF) systems that have detection limits in the
tens to hundreds of ppm range.
The system is delivered to si