43 / 68
May 2016
MODERN MINING
41
MODULAR PLANTS
feature
does not constitute a ceiling as we can imple-
ment modules in parallel – in fact, we’ve quoted
on plants as high as 1 000 t/h, consisting of
4 x 250/t modules,” says Westcott. “As a rule of
thumb, I would say that modularisation works
best for throughputs of up to 800 t/h. If you
go much beyond this, the materials handling
arrangements – notably the conveyor systems –
tend to become too complex and start to negate
the benefits of modularisation.”
DRA’s modules are designed to process coal,
iron, diamonds, chrome, manganese and min-
eral sands, as well as metalliferous ores (both
precious and base metals) that are disposed to
pre-concentration and the removal of gangue
using DMS and gravity separation technologies.
Unit processes that can be addressed include
crushing and screening, dense medium and
spirals separation, filtering and thickening,
along with materials handling and storage.
The company is particularly strong in coal
and its modules can be integrated for various
coal wash strategies including production of
‘Eskom’ product, primary/secondary wash,
production of sized products, as well as phas-
ing or production build up. DRA has also done
well with modular diamond plants, supplying
everything from small exploration and bulk
sampling plants at one end of the spectrum
through to 240 t/h facilities using single and
twin-streamed DMS modules. These plants
have included modular recovery sections, as
well as scrubbers, multi-stage crushing circuits,
thickeners and flocculation plants.
In respect of base metals, an effective appli-
cation is the installation of modular DMS
technology to reduce ore cut-off grades and
upgrade mill feed, in the process reducing
reagent consumption and electrical power
requirements. A number of copper, zinc
and nickel mines have benefitted from this
approach. The suitability of an ore to this
method of upgrade is dependent on the results
of densimetric testwork.
Although a library of pre-engineered stan-
dard module and standard designs is available,
DRA can also undertake the engineering and
design of tailored modules. “We don’t have a
‘one size fits all’ approach – we accept that cli-
ents might have special requirements and we
are more than happy to accommodate these,”
says Westcott.
He also points out that DRA has partnerships
with key equipment vendors when it comes to
componentry such as screens, magnetic separa-
tors, pumps, crushers, cyclones, thickeners and
water tanks. “At the end of the day, the plant
we supply will have DRA’s name on it – which
is an assurance of quality and reliability,” he
states. “This in turn means that we have to
ensure that all componentry meets the highest
standards and is fully backed with excellent
spares and service support; we only source
from reputable companies who are leaders in
their field.”
Geographically, DRA has supplied its mod-
ular plants throughout Africa and around the
globe. Says Westcott: “We’ve sent our plants to
Australia (where we have a 50 t/h chrome plant
working), Canada, South America and Russia.
In fact, Russia has been a great market for us and
we’ve supplied 12 plants over the past 11 years,
all of them to diamond producer Alrosa. Our
latest contract – which we’re just finishing off –
is for four modules, two of 65 t/h capacity and
two of 110 t/h, in Siberia. The site is extremely
remote and to get there from South Africa takes
three days of flying – but we pride ourselves
Coal modules can be
integrated for various coal
wash strategies includ-
ing production of ‘Eskom’
product, primary/secondary
wash, production of sized
products, as well as phasing
or production build up.