SCREENING AND WASHING
and invested in screening media manufacturing
capacity. The introduction of the hammerless
attachment system is yet another step we are
taking to help our screening media customers
minimise downtime and maximise productivity,”
says Larsson.
The new attachment system is currently
available as a standard option for Trellex 305PS
screening media in the most common build
heights (40-60 mm), and will soon be introduced
for additional build heights.
Screen OEM and media supplier
collaboration
Collaboration between the OEM of vibratory
screens and the screen media supplier is key to
ensuring the lowest possible cost of ownership
while continuously meeting tonnage throughput
requirements.
According to Derrick Alston, Executive Director
of vibratory screen OEM Kwatani, the company
engineers screening machines for a c ertain
weight and performance of screen panel.
“We then test the screen extensively in our
modern workshop facilities to ensure that the
screen panels specified by the customer will
deliver certain throughputs and end-products for
that application,” says Alston. “When screens are
later changed, they still need to be carefully
integrated with the structural and mechanical
features of the screening machine.”
Kwatani custom engineers and manufactures
vibrating equipment for all feeding and screening
requirements, from smaller machines of less than
a tonne to 50 t machines with throughputs of up
to 7,000 t/h.
Kenny Mayhew-Ridgers, Kwatani’s Chief
Operations Officer, says that once the machine is
operating in the field, there are instances where
panels are fitted that add substantial extra
weight to the screen.
“We sometimes find that the screening panels
on our operating machines substantially exceed
the weight of what the machine was initially
designed to take,” says Mayhew-Ridgers. “This
extra weight can change the dynamics and the
centre of gravity of the screen so that for
example, it is no longer aligned with the exciter
drive. This can cause damage to the machine and
even the building if not quickly identified and
resolved.”
Alston highlights the importance of keeping
OEMs ‘in the loop’ when changing panel types,
so that the fitting of new types of panel does not
have unintended impacts that could be
detrimental to the machine’s life-span or
performance.
“With our depth of expertise, we can advise
from a mechanical point of view on areas where
problems could arise,” he says. “We aim to
cooperate with other stakeholders wherever
22 International Mining | OCTOBER 2017
possible, and have
Experienced Kwatani service
worked closely with team personnel on site
inspecting a screen prior to
end-users and
installation
panel suppliers to
find optimal
solutions.”
Kwatani’s
qualified and
experienced in-
house design and
technology teams
undertake custom
designs to
customers’ specific
application and
processing
requirements.
These designs are supported by finite element
to expectation in terms of recoveries, tonnages
analysis (FEA) modelling competency, a
and efficiencies.
sophisticated test laboratory, and years of
“We also ask whether there have been any
research and development.
changes in the upstream process,” says
Schoepflin. “This is to check whether the feed
Screen maintenance – the right
that the vibrating machine is receiving is still in
approach
line with the original specification of the unit;
Cost pressures often force mines to make difficult
orebodies often change, and this can affect the
decisions about how they approach the
material and the processing requirements. We
maintenance of their vibrating screens; OEMs can
need to establish whether the equipment is
ease the trade-offs by offering solutions that
actually still fit for the purpose for which it was
match customers’ specific needs and resources,
designed.”
according to Kwatani CEO Kim Schoepflin.
This leads to a list of issues that must be
“While most mines have been through a
addressed, which in turn must be prioritised;
difficult period, each one has had to deal with it
starting with any vibrating machine that is close
in its own way,” says Schoepflin. “As an OEM, we
to destruction as costly downtime due to sudden
need to understand their specific conditions and
failure must be decisively avoided.
constraints before we can build a solid
Refurbishment of the equipment by the OEM is
partnership that works for both parties.”
usually significantly more cost effective,
She says it’s about adopting a consultative
compared to a new replacement, when it is
approach when dealing with customers, not just
performed timeously.
taking them a catalogue of products and services.
“On the basis of this assessment and the
Listening carefully to the customer is vital, to
resulting priority areas, we then agree on an
learn what their challenges and limitations are.
action plan with the mine that takes into account
Mines have tended to cut capital expenditure
their human and financial resources,” she says.
as a result of depressed commodity prices, which
“Low commodity prices have also meant that
means that the working life of equipment, like
mines have lost vital skills to operate and service
screens, is being extended. At the same time,
their equipment.”
however, the necessary maintenance is often also
Along with many maintenance positions on
cut back, creating a serious risk of failure and
mines being consolidated to aid cost cutting
unscheduled downtime.
efforts, there are also high levels of staff
“A vibrating screen is one of the smaller and
turnover; for OEMs, this means often having to
less costly items in a plant, but it is a critical
deal with new and inexperienced staff who need
element that can bring a whole module, or even
considerable support in guiding the maintenance
the entire plant, to a standstill if it fails
process.
unexpectedly,” she says.
“The maintenance teams are frequently
“At Kwatani, we typically start our intervention
responsible for a wide range of different
with an on-site audit to assess the situation in a
equipment, and lack the specialised knowledge
plant, beginning with a look at the mechanical
that is so crucial to keeping vibrating screens
state of the vibrating equipment in its operational
performing optimally,” she says. “This is an area
and non-operational state.”
where close and ongoing contact between the
A visual inspection allows any damage to the
mine and the OEM is crucial to achieving the
steel section or wear to be identified. The next
lowest possible ownership cost over the life of
question is whether the equipment is performing
the machine.” IM