December 2015
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World Coal
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31
Brian Evans and
Grant Graber, Terra Nova
Technologies Inc., USA,
explain how the company’s
portable conveyor design
concepts, which were orignally
developed and patented for
heap leach stacking (HLS),
have been applied to dry
tailings stacking and can be
applied to coal operations,
including in-pit crushing and
conveying.
I
mproved mobility and new designs for mobile stacking systems developed by
Terra Nova Technologies Inc. (TNT) since the late 1990s allowmine‑for‑leach
operations to minimise downtime during operation, while efficiently using
available stacking areas.
Traditionally, these operations were stacking materials parallel to shiftable
conveyors. These conveyors had to be moved numerous times – typically about
one meter at a time. During the shifting process, the stacking process was
disrupted, which forced the crushing and, if used, agglomeration plants that fed
the leach pad to shut down.
Often the tail end of these shiftable conveyors (where material is transferred
onto them) had to remain at a fixed location and, due to the resulting geometry,
the area of stacked ore eventually formed semi‑circular areas. Consequently, the
usable stacking areas were often tapered in a series of ‘pie wedge’ shapes toward
the tail. It is challenging to stack multiple layers of material on such a
semi‑circular footprint, and this could in turn limit the total height of stacked
material to the height of the equipment’s discharge point.
