ORE SORTING AND GRAVITY_proof 27/04/2016 10:07 Page 6
ORE SORTING AND GRAVITY
boxes which can take days depending on the
number of matrix boxes installed.
Even though standard screens installed
upstream of the WHIMS provide some protection,
its use has proven that it is a good but not 100 %
safe solution. The wear and shape of the PU
panels typically used for these screens do not
completely prevent oversize particles ending up
in the screen underflow. Over time any oversized
particles in the WHIMS feed create the above
mentioned issues.
In order to achieve the best protection and
most reliable operation a new concept had to be
developed. Protection screens had to be
designed to ensure that once a particle has
passed it, it should also pass through the matrix
box openings. The solution was to use screen
panels made out of the same steel used for
matrix boxes, applying the same shape of the
matrix box gap in order to prevent oversized
particles entering.
This goal was achieved by cutting slices of
proper thickness from the grooved plate matrix
boxes. These screen panels are curved to an
extent suitable to provide a path with an opening
beginning at the standard matrix box gap and
widening gradually towards the output. This
geometry allows for a loose path for the outgoing
undersized particles.
The slurry feed flows inside the rotor and is
screened by the matrix screen panels. The
19th International Seminar on
Paste and Thickened Tailings
July 5-8
oversized particles travel inside the rotor at a
speed proportional to the rotor revolutions.
Transport is facilitated by the rotor’s 10° slope.
Oversized particles are discharged at the end of
the rotor through the oversize output. All other
particles suitably sized for the WHIMS process
pass through the screen gaps to the undersize
output discharge. To increase the protection
grade the gap openings of the screen panels are
smaller than the gaps of the matrix boxes
installed in the WHIMS. Water jets mounted
above the rotor remove the particles which got
stuck in the gaps. These water jets keep the rotor
clean so that it can perform its screening function
PRE LIMINARY PROG R AM
E XECU TIVE COMMIT TE E
Over 70 abstracts have been approved
by authors from 17 countries
chair
Hubert González
Tailings and Water
Management Manager,
scm Minera Lumina Copper,
Chile
SEMINAR THEMES
Hotel Grand Hyatt
Santiago, Chile
Gold Fields’ Granny Smith plant incorporating
Gekko’s purpose-designed gravity box
Paste • Thickening • Filtering •
Rheology • Chemicals • Tailings slurry
transport • Pumping • Tailings beach
slope • Testing • Case studies
executive director
Carlos Barahona
General Manager,
Gecamin, Chile
technic al coordinator
Sergio Barrera
Senior Tailings Consultant,
Delfing, Chile
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FOUNDING BO DY
AUSTRALIAN CENTRE
FOR GEOMECHANICS
24 International Mining | MAY 2016
O RG ANIZ E R
INS TIT U TIONAL PAR TNE R S