Mobile stacking systems of this type
have been designed and supplied by
TNT for dozens of mines, including
Bulghah (gold) in Saudi Arabia,
Kisladag (gold) in Turkey, Dolores
(silver) in Mexico, Lomas Bayas (copper)
in Chile, Gualcamayo (gold) in
Argentina, Somair-Arlit (uranium) in
Niger and, most recently, Bouly (gold) in
Burkina Faso.
Self-propelled portable
conveyors
Two patents awarded to TNT in 2000
(for a new heap leach process, as well
as a new tracking, propulsion and
braking system for bridge
tripper/hopper cars) led to TNT
developing larger portable conveyors
that can sustain longer durations of
uninterrupted stacking, which results
in less overall scheduled downtime
during operation. As tonnage increases
(e.g. beyond 3000 tph), the rate of
deposition of material increases such
that the retreat/advance rate would
become relatively high, increasing
shutdown frequency (leading to a
higher potential of shutdowns). If the
portable conveyors can be made
longer and self-propelled, clearly the
frequency at which the units must be
removed (retreat stacking) or inserted
(advance stacking) can be reduced.
In 2004, TNT was awarded US
patent 6 782 993 B2 for mounting a
portable conveyor on tracks instead of
rubber tyres, so that it was fully
self-propelled (via all-track propulsion
and an onboard generator).
These Super Portables
®
make
operations on the leach pad more
flexible in multiple ways: because they
do not require any other equipment for
their relocation; they can be inserted or
removed from the stacking line with a
briefer shutdown; they permit
operators to be positioned more safely,
while equipment is travelling; and they
increase the stacking system’s overall
mobility, especially on equipment
ramps.
The Super Portable
®
design was used
at several copper leach operations before
it was first used for stacking
filter‑pressed tailings. The first
Super Portable conveyor designed by
TNT was a 215 ft conveyor in Peru.
Feeder/breaker and Super Portables
®
, and a down-bench conveyor in a
multiple‑bench pit feeding an overland conveyor.
Source: Joy Global.
Feeder/breaker and Super Portables
®
operating in a multiple-bench pit.
Source: Joy Global.
A stacking line of 250 ft, Super Portables
®
moving 7200 tph up a ramp from an
overland conveyor/mobile tripper to the stacking area of a multiple-lift copper heap
leach pad
34
|
World Coal
|
December 2015
